You Think You Know But You Don't - Slip Angle Explained in a Way You Will Understand

[@d4a]

100 cars that changed the world: amzn.to/3DGXDf6 Stem engine model: amzn.to/3Y5iZLv 1-2-3 count with Car parts: amzn.to/3jxP7Z6 Patreon: www.patreon.com/d4a

[@ivorscruton5121]

To follow up on this useful information, an episode on how braking and acceleration, during cornering, can imbalance the slip angle. This phenomenon is probably widely misunderstood by those other than professional drivers.

[@youngrider7606]

Can you do a video about lightening things like flywheel pistons rollers and others. Benefits and negatives, even dyno numbers from only lightening. i want to see if is a myth that too much lightening loses power at high rpm

[@trumanhw]

I feel like static and dynamic friction .... ei, traction vs sliding might have been worth mentioning in here? Anyway, love your stuff dude. Hope all is good in Serbia. (but that is not how wings or spoilers work ... which I'm sure you know bc you really do seem good at physics).

[@mojeimja]

so, what if instead of normal rubber wheels we use steel cylinder-like drums, that cannot deform. Would we drift a little every corner instead of "normal" turning?

[@rodintoulouse3054]

Another fantastic and simple explanation. Once again you prove how knowledgeable you are. “If you can’t explain it in easy to understand terms, you don’t understand what you are talking about”. Well done!!!

[@dickieb2233]

Wow, hold your horses there. Your audience has to have a certain ability to understand a situation. Balancing the knowledge with their ability is the skill of the orator; similar to slip angle and cornering force in fact. This chap took more than 16 minutes to explain that if you turn the wheel too much then you will attain understeer.

[@rodintoulouse3054]

@@dickieb2233 your point being what? That he doesn’t understand the subject? that he didn’t explain it in a simple manner? that he took too much time? That he didn’t explain it to right audience (subscribers interested in the subject)? … your are probably right on all counts as opposed to everyone else that agrees with me.

[@dickieb2233]

@@rodintoulouse3054 Thank you Rod. I may not have made my case very well. The salient point is that someone who is engrossed in their subject matter may not be very good at explaining to others. For example, Alan Turing was not very good at explaining things but one could not say that he didn't have a good understanding of his field. In fact, it is a good way to recognise brilliance, for such a person may well seem disjointed in their delivery. Their brain skipping several levels of explanation, assuming their audience will be up to speed. Forgive me if I came across as confrontational; I was merely offering a different angle.

[@jetplume]

Hmmm, I guess university students shouldn't have to take lower division classes before they take their upper division classes. The professor just has to explain the material in easier-to-understand terms! Anyway, while this video is maybe useful for getting a layperson to understand that there is more than meets the eye to vehicle dynamics, it doesn't really explain the mechanism behind the generation of cornering force, which is actually lateral displacement of the contact patch. The concept of "slip angle" is only useful because yes, the contact patch deforms at an angle to the tire centerline, and we can describe many things in terms of slip angle as a measure of deformation. It also confusingly spends a lot of time dwelling on centrifugal force, which isn't really relevant at all and is a "psuedo-force" (it can only be observed if we define a very special reference frame) and shouldn't really be relevant to this discussion at all. So this sort of comment really rubs me the wrong way. If you don't understand something it's not necessarily because someone just needs to find a better way to spoon-feed you.

[@rodintoulouse3054]

@@jetplume well, I guess you’ve never had the pleasure of being a teacher and having the satisfaction of your students learning something new instead of having the satisfaction of proving you know more than them. I hope you get to experience it one day.

[@gabrocki]

You're still the GOAT man, this my absolute favourite channel for car related educational stuff. Your videos never disappoint.

[@MrMcFrizzy1]

fr im about to buy a notebook and just go through all dudes videos to remember ts

[@76horsepower]

I came to a similar conclusion at some point in the past when I tried to understand how one can steer slightly into a strong side-wind while continuing to drive straight on a highway. My thought was that the tread blocks were effectively “walking” sideways. Thank you for the much more engineering-minded explanation! Kudos, as always!

[@stalincat2457]

Cabover cars like the Subaru Sambar can suffer from this HORRIBLY. Like... steering wheel in the 2-o clock position while driving straight ahead during gale winds. Reinforced tires with an extra layer of ply improved things immensely. Just be ready for raised eyebrows when you're asking for reinforced 13" tires for your 2000lbs van.

[@JSBax]

When this happens, you realise "slip angle" really does mean slip! The tyres are providing lateral force even though the car doesn't turn into the direction of the tyre. Only way this works is if they're slipping

[@benchleyfalconer-kc5hj]

Same idea as if driving along a slope. To maintain a straight path, you have to steer slightly uphill.

[@driverjamescopeland]

I drove a 40 ton commercial truck for the better part of 15 years. Countering the often seemingly perpetual winds of the Midwest and Western USA was a mind wreck, at first.

[@Trombonauta]

The twisted rubber in your tyres is also what pushes your steering wheel to a centered position, aligned with the rear wheels.

[@Devo491]

I've been a rev-head for 70 years, and I've learned more in the last couple of years than the previous 68, thanks to the high-info content of your channel, and a few others. Thanks for the intensive research, and amazing graphics!

[@dorsetwarrior3870]

My boy getting to 700k today for sure . Congrats in advance!

[@THEANIMALGUY]

I'll also congrat

[@lcv0711]

He did, congrats !!!

[@Tanquavioousdingleberry]

Congrats bro

[@Mustangblack187]

🐺🖤🐧🐧🐧

[@Lupine.]

2 months-in: 806k The best automotive engineering channel on YT. .HandsthefuckDown.

[@scottlyman7427]

This was great. Slip angles are always a tough topic to explain. Next, could you tackle the topic of contact patch aspect ratios? Wide tires have wide but short contact patches. This results in each piece of the tire's tread being part of the contact patch for a shorter time. Consequently, for any given slip angle, each point on the tire's tread will experience less lateral displacement before it finally exits the contact patch. This can contribute to the tire tolerating a larger slip angle. But it also reduces feedback at the adhesion limit. When the tire begins to lose adhesion, the lost of grip starts at the rear of the contact patch where the lateral displacement of the tread is greatest and the rubber's restorative force is highest. As the rubber's restorative force (the force pulling it back to it's natural position) exceeds the friction that binds it to the road, it begins to release that grip on the road. Since it happens first at the rear of the contact patch, and then progresses forward, it effectively shortens the contact patch and shifts the centerpoint of the contact patch forward. This movement of the contact patch produces an effective change in the self centering force (because the contact patch is closer to the point where the pivot axis of the wheel intersects the ground), usually causing the steering to feel lighter as grip deteriorates, because the change in camber reduces the centering force produced by the steering system. In a tire with a long, skinny contact patch, this progression is more gradual, making it easier to detect and react to. In a tire with a wide, short contact patch, the loss of grip starts at the rear by has shorter distance to spread before reaching the front of the contact patch. This not only makes the loss of grip more sudden, but it also reduces the degree to which the contact patch centerpoint can move. Thus, wide tires cannot produce as much change in steering centering force at the limits of adhesion, compared to narrow tires. It'd be great to see some of these topics covered in your enjoyable, understandable, well-illustrated style. Edit: For some reason I mentioned camber when I was thinking about the contact patch and the self centering effect of caster.

[@jorgemeireles5549]

Whatt???

[@scottlyman7427]

@@jorgemeireles5549 Sorry - that was confusingly written. I just corrected my erroneous reference to camber. Should be clearer now.

[@SpookyDeCat]

thank you for the videos. although I consider myself a life long motor head (I am 61 years old), I have learned more engineering behind the drive in your videos than I have anywhere else.

[@sciteceng2hedz358]

This man needs an award for not making KZbin dumb like most other channels. Love it!

[@RyanSheppard]

Warning: this video has spoilers

[@jfcjic3935]

I'm sorry I ever doubted you

[@renoysilburn4037]

😭😭😭

[@SehajSingh94]

Brilliant

[@Theokoko22]

Very well done😂

[@Fak_It]

This guy, my tuner, and my usual mechanic are pretty much the only people I listen to regarding cars.

[@d4a]

I love the company, thank you ☺️

[@C.I...]

I imagine the grip graph is a lot smoother for cross-ply tyres - hence a lot more dancing around the limit of grip.

[@Obi-WanKannabis]

it's two fold, bias ply tyres can't be as wide, and the narrower the tyre the smoother the curve.

[@5naxalotl]

yes to both these comments. the pre-radial F1 tires were thin and had huge slip angles, and this made it easier to feel the peak approaching or that you were past it. for my money this made cornering more interesting, having to think ahead more with steering inputs. and spectators had the spectacle of seeing cars mid-corner pointing ten degrees sideways from the direction of travel. but a good driver would rather have more grip but more sudden transitions. unlike hollywood car chases taking corners sideways, pro drivers are freakishly good at knowing the exact line and speed to get maximum grip without risking a spin. you're still dancing around the limit *all the time* , but the adjustments are more microscopic ... which is why it's more interesting to be driver rather than spectator

[@hunchanchoc8418]

@@5naxalotl That suggests that a wider tyre will always provide more cornering grip. But surely there must be some upper limit to how wide a tyre you can fit (in theoretical terms, not practical terms) before cornering grip starts to reduce again? What if the length of the contact patch gets so short that there isn't 'time' for sufficient deflection to take place??

[@m34275]

​@@5naxalotl spectators are cucks

[@dickieb2233]

@@hunchanchoc8418 What an interesting way of looking at that. A very soft tyre will deflect greater than a hard compound. However, a wider tyre will grip/corner better than a narrow one unless aquaplaning or cutting through snow. Front tyre specs are determined by aerodynamics too, hence the six wheeled Marches.

[@joseph-n8y]

I read so many articles to understand what is and how centripetal force acting on car when it drives in circle. No one explained good until someone recommended me this video. Very good explanation. Just one point,as i know there is no centrifugal force,it is a fictitious force. There is only centripetal force.

[@frogandspanner]

First, let us forget the stuff about 'centrifugal force'. The main force involved here,centripetal force, provides the acceleration of the vehicle towards the centre of curvature, and is

[@black_n5492]

One of my favorite channels on cars. I've learned so much about first principles watching your videos. Looking forward to more!

[@CBD47]

One remark: centrifugal force doesn't exist in reality. It just a simplification. The truly acting forces while cornering is centripetal force(which tries to force car to turn) and it's counterforce - inertia(which tries to make car go straight). Not a big difference in terms, but huge in understanding real turning physics. Despite this anyway this video is still one of the best popular explanation of car turning on youtube )

[@freshrockpapa-e7799]

Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force, it definitely isn't a simplification nor a mathematical trick.

[@jagadheesh2895]

A well explained detailed yet simplified way of describing tyre slip angle. Helped a lot.

[@enzoferrari8980]

12:03 now this explanation might lead you to the wrong assumption that you always should apply rotation to the steering wheel linear with like 5-6 degrees per contact patch (just referring to the used numbers) but theres much more to it. a car has very different grip levels through the process of cornering. earlier in the video there was the clip of the dodge viper acr extreme aero going through brünnchen at the nürburgring. in that clip you can see it pretty well, the corner has a kind of a bump at the entry and you saw the cars front do a little dip afterwards. right in the moment after the bump when the cars front comes down again and compresses the front springs and dumps its weight back into the tires, you can apply much more steering angle at once (again because of the momentarily higher grip levels) and then take even more speed into yhe corner because you dont need to apply so much more angle to the steering wheel at the remaining part of the turn. the most important thing in racing is to control the balance and forces on each tire all the time and use it to position the car into a turn, keep it straight and controlled while exiting and using all of the available grip all the time. at the viper shown in the clip, a typical front engine rwd car you will be using a trick as well, which is downshifting in the right moment to get an additional braking effect on the rear tires just when the clutch dumps back after the downshift, by the engine brake and the higher resistance coming from the now faster rotating engine, gearbox and drivetrain. by that you can shift some of the cars weight to the front when the clutch engages and use that additional grip i explained with the bump at the corner entry and shift it back and use the rear tires grip as much as possible once the clutch releases again and get back the balance over the car and try to spread the load equally to each tire. this is mostly used in f/r cars because the engine in the front rather makes the car understeer and with the driveshaft in the rear you can counter that by throwing it into the small moment of oversteer. mid engine cars can use that as well but theyre naturally already more oversteery and snappy and more sensitive anyway.

[@Clumrat]

Useful information, I didn't think of using the engine braking in that way

[@damiansmith5294]

So if I'm understanding what you're saying correctly, when he shows the downforce on the graph, the increased cornering force should be at a sharper slip angle?

[@professorscrim5303]

Have a day off bud.

[@johnhunter7244]

First correction: the placement of the engine in any sports car (basically just within reason, not crazy 75-25 weight distribution) doesn't have a direct impact on the under/oversteer characteristics of the vehicle. What affects over/understeer is a combination of weight distribution/centroid location, suspension, and tire setup. You can make front engine cars naturally oversteer fairly easily. Second: with ABS, you shouldn't have to try that downshift technique. Just hit the brakes, if the rear has more grip then it will have the brakes applied the perfect amount, assuming a good ABS system. It would be very easy to lock up the rear tires and cause you to crash with the downshifting method.

[@enzoferrari8980]

@@johnhunter7244 that weight distribution isnt the only factor about under or oversteer is obvious, didnt say that. but youre saying that its a part of it as well, so its not really a correction. but the part with the abs was misunderstood i think. i know that a good racing abs can provide you the right amount of grip at all 4 wheels. but what i mean is rather that you use the engine brake in the moment of downshift to overcome the maximum applied braking force the abs lets you to give to the wheel. for a small moment there is the brake force ruled down by the abs plus the engine brake and that will bring the wheel over its maximal usable grip level. it wont lock up though, because the abs wont let off, theres just the engine braking coming on top. so as a spectator, you will neither see a lock up nor smoke at the tire, and thats because the speed difference is very small, for example 90kph of the car covering actual distance and 80-85 kph of the wheel rotating at its contact point to the road. this will make the rear come loose a very little bit and make it step out further than just with abs. but because the engine brake only works for one or two tenths and the speed difference is that low, it will catch itself automatically. thats because no abs on the planet can use 100% of the available grip. the better it is, the closer it comes to 100% but there is no perfect case. there are factors like downforce pushing the car down resulting in a bigger contact patch, or a bump in the road affecting the tire in different ways and thats what you need to learn to use with that downshift technique. the abs allows you to use 99% of the grip, so you quickly bring it to 100.5 or 101% and over the next lets say one second, this number will automatically decrease back to 100.2, 100, 99.8% and lower and lower back to 99% by catching itself. and in that timespan you bring more rotation into the car and get a steeper angle into the corner so that you need to do less turning over the front wheels in the rest of the turn and step on the gas earlier

[@sandroxino]

I had no idea, this is fascinating honestly

[@Face2theScr33n]

I like to think of tires as "feet on a wheel". For each foot length, that is all the tire you have. It's helped me avoid at least a few scrapes. Great video!

[@SusedatLubo]

Imho the go to channel on youtube about in depth and understandable car dynamics!

[@oler777]

I remember in 2011 watching ads for Forza motorsport four and then slowing down the footage to show that the tire manipulation was actually working like you mentioned in this video

[@finnojk]

This is an incredible channel, thank you, I learned so much.

[@MachinistSquare33]

Excellent way of explaining how large lugged 4wd tires get cupped. The hand over hand really makes the visual

[@diogenedigionaakagiuseppe8676]

wonderful explanation, as always. I discovered your channel a few weeks ago and I'm watching little by little all your videos and I really appreciate them. Complimenti davvero, sei un grande, continua così 👍

[@d4a]

Grazie!!

[@L_ednik]

Thank you for clarifying that slip angle is not drifting. I'm so tired of these "racers" calling drifting "slip angle" because they watched 7 minutes of TSRB

[@ravenheart369]

I've become this channel subscriber as I like this channel more than Engineering Explained because he explains everything with comprehensive animations which makes it so much easier to understand. Keep doing this great job. All the best

[@AbrahamArthemius]

Another thing to add is that he uses words that are relatively much simpler to understand. Sometimes EE explains things a bit too quickly IMO.

[@ravenheart369]

@@AbrahamArthemius Good point indeed

[@AyyGin]

Love EE but I agree. These animations and visuals are extremely helpful when trying to understand these concepts.

[@SupraSav]

Seeing a new D4A video, or even revisiting some old ones is always a mini-event. I make a snack, grab a drink and a sketch book

[@Reziac]

So this explains a great deal about... -- tire wear patterns (please do a video on this) and why turning circles wear them out -- sidewall behavior (cracks eeek!) -- handling differences between high profile and low profile tires (please do a video on this too!) -- and perhaps why I prefer stiff sidewalls (aside from load capacity, which I need... I put six-ply on a sports car and lordy did it improve grip on ice, I no longer needed studded winter tires.)

[@unnamedfornow2381]

Im really thankful that you are willing to sacrifice your time to make videos to explain complex stuff in simple ways to beginners in automotive world

[@Teh-Penguin]

Good explanation overall with a slight exception. *_The "centrifugal" force does not exist._* It's a so called "apparent force" resulting from your body wanting to move forwards while the car wants to push you INTO the curve. So there are no forces pushing you out. Now what you called centrifugal force at 7:48 is actually frictional force.

[@lpls]

I personally prefer to put the reference outside of the vehicle and think in terms of centripetal force. Clicks better at my brain. I find it easier to visualize as the sum of all forces resulting as a vector pointing to the center of the curve (and necessary to change the velocity vector direction). Whenever I hear centrifugal force my brain kind of replaces it with "just inertia".

[@freshrockpapa-e7799]

Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force, it definitely isn't a simplification nor a mathematical trick.

[@argonsparrow]

Video title checks out. Thanks a bunch! This was really helpful for explaining the underpinnings of how cornering works, ties everything together.

[@skylinegeert]

Loving the way on how you explain things in your videos

[@sandrojohmann2602]

Sensational explanation. Love it!

[@williamyang8799]

I just started getting into sim racing so this is very helpful knowledge. amazing video

[@leanspo]

Excellent! I've never drove a car myself but I've played a lot of racing games and I realized how important is to choose the right type of tire and the pressure

[@maglev_]

seriously the greatest car channel out there right now everything is explained well in terms anyone can understand and it’s always useful information keep up the good work d4a

[@Mayyouknow]

9:41 "Friction cannot generate movement". Yes it can, without friction no car would be able to accelerate at all, infact friction causes the car to me able to change its velocity - both turning sideways and speeding up or down.

[@timmyhasheart]

This isn’t entirely right, and the small bit it is right, it’s only really correct getting from straight steering wheel to final steering location, then once you’ve steered as far as you need to steer, then you’ll continue cornering with none of this happening because the car has 4 wheels, it’s like you’ve disregarded the back wheels, this seems more pertinent to a unicycle? Love your vids dude ❤

[@DrR1pper]

Not true or else the tyres would no longer be producing cornering force which is necessary for the car to maintain cornering. All four tyres will be sustaining a slip-angle for the car to be maintaining a turn radius. No slip-angle, no cornering force, no turning.

[@supawonk]

Thanks for calling out the misleading videos on KZbin and spending the time to correctly educate the masses on this stuff, incredible work as always :)

[@dksaevs]

Evidently my wife doesn't believe in cornering force... SHE ALWAYS TELLS ME TO COME STRAIT HOME. This is a great video that I'm sharing with a couple of would be race car driving friends.

[@shifty5917]

Insane video. I feel 10x smarter after watching this.

[@sterlingroberts6240]

Another excellent video, sir! I wish you all the best in life!

[@julkiewitz]

Wow, thank you now it makes so much more sense that drivers do micro corrections when taking a tight corner at high speed whenever they notice that they are starting to lose grip. It temporarily reduces the slip angle and as a result increases grip.

[@eriktempelman2097]

Cool stuff! Fun fact: you can estimate the size of the contact patch by dividing the force per wheel (in Newtons) by the tyre pressure (in Newtons per square metre).

[@nahometesfay1112]

I took a class on Vehicle Dynamics and while I'm certainly not an expert I think this is a great introduction to the topic!

[@johnlovett8341]

Awesome as always. Thanks. I might use the term "inertia" rather than centrifugal force (or centrifugal inertia) in a few places at the beginning. Then again, thinking about most of this is new to me.

[@DylanL69]

It's centrifugal force because it's starting to go sideways inertia is more for going straight

[@Mayyouknow]

@@DylanL69 Yes you are right, but so is also John. The body inside the car experiences no outward centrifugal force with respect to the asphalt. If the tires would suddenly stop having any friction the car and the people inside would continue moving straight on, not outwards.

[@DylanL69]

@@Mayyouknow yeah I know that

[@Mayyouknow]

@@DylanL69 I do not think you knew that. There is no centrifugal force in the reference frame of the ground. So it's not centrifugal force.

[@zhutwo]

@@DylanL69 Inertia applies to all matter with mass regardless of direction of movement, or if it's even moving at all. If you want to change the motion of a mass, you need to fight its inertia. The car was going straight, and to get it to change direction, the molecules of the tires pull on each other, the wheels, the axles, the chassis, and then you because everything in that chain has inertia to keep moving in the initial direction. Centrifugal force is just a pseudoforce generated by inertia of rotating masses. OP is correct that inertia is the more accurate term here because it's independent of frame of reference.

[@jordonhenderson5094]

Fantastic explanations. This is my 2nd video from this gentleman, and he explains it in a way it's easy to understand.

[@CVS19851]

Absolut MASTER! You really nail every topic you explain.

[@sigmakage4705]

Im not don watching yet, but this is incredible. Now I know why more pressure on the front tyres generates understeer. The fact that iRacing simulates this is nuts too!

[@Tyr1001]

great video as always. Another subject I'd like to see touched on is how the suspension and loading effects tire deformation and cornering

[@mindtraveller100]

Yes. And also tyre pressure and tyre width.

[@d1zguy864]

Yea, you can observe this by keep the steering angle the same on a on or off ramp with a given acceleration rate. Give it less and the corner gets taken sharper with same slip angle, accelerate or shift weight to rear and it gets wider.

[@MrPrime-mt8dd]

this guy is like a miracle for my understanding, it's so satisfying

[@dieselscartalk4146]

I become big brain every time I watch one of your videos

[@Crainshaw83]

this what made me fell in love with simracing, that infinite search for the perfect balance through corners, but it is so satisfying when you hit it

[@233kosta]

There is a very big difference between a wing and a spoiler, aerodynamically speaking. It's worth keeping that in mind.

[@captainjigglebeard7785]

Was just about to comment this. Spoilers are for drag reduction and increased fuel mileage, whereas he describes a wing.

[@233kosta]

@@captainjigglebeard7785 Spoilers force flow separation, I don't see how that reduces drag

[@Simon2million]

Ah I’m not the only one then that was about to comment on the difference between wings and spoilers

[@Simon2million]

The Audi TT is a classic example of a spoiler , when originally designed the shape of the car had the effect of air clinging to its top surface and the whole car lifting up at high speed as it was working like a wing, the addition of a spoiler broke the air flow and cured this problem.

[@233kosta]

@@Simon2million Yeh, I'm not sure what's worse with that one - the lift or the separation instability

[@Subeebles]

Another smash hit of an explanation! 10x more informative than even the current auto school curriculum. Bravo, sir!

[@chat66]

Great video, but one thing. Centrifugal force isn’t actually a real thing. There is no force pushing the car towards the edge of the road, it’s just the inertia of the car wanting to keep the car going at the same velocity (that is speed and direction) it is currently going at. This creates the illusion of a force pushing outwards.

[@DawnBriarDev]

You're arguing semantics. Inertia is a measurable force. Using a simple term to summarize the effect of inertia on a rotationally constrained object is an effective tool to communicate a common phenomenon of combined circumstances. So no. In practical terms, centrifugal force is a real thing in that it is a useful description of more fundamental, combined phenomena. I hope you realize how silly you sound arguing against the use of a term to describe a combination of circumstances. Like calling something water, when really it's just two hydrogen and one oxygen molecule.

[@chat66]

@@DawnBriarDev I’ll send you my physics professors email if you want to argue about the terminology. I more or less just think it’s cool that there isn’t an actual force that creates it but an inherent property of matter. :)

[@freshrockpapa-e7799]

@@chat66 Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force, it definitely isn't a simplification nor a mathematical trick.

[@TheKaptainKombat]

I have too many things to repair or replace on my vehicle to be feeling this inspired to go enjoy a brisk drive. Thank you for the enlightening information as always!

[@llys3742]

05:10 Small correction: judging by the turning radius, the steering wheel should be constant, not increasing the steering angle. (Edit: While reading further into the subject, I found that this video is plagiarized from YourDataDriven's article on tire slip angle. Animations, eraser analogy and hand analogy are ripped straight from said article. At least give credit! Unprofessional.) Also, four wheel drift is a real technique mostly used by pre-war racers. (Look up Fangio or Nuvolari) Old tires (bias-ply) grip the best at a much higher slip angle, and aligning all four tires at the best slip angle (zero-counter drift) yields the highest cornering force.

[@alecmillea4539]

Absolutely correct glad to see someone mentioned this! Only thing of note to add is that while you are correct on zero counter steer slip angle yielding the highest cornering forces it also produces a large amount of tire wear and heat generation. Thus while it is of high importance to take advantage of this method during a qualifying lap to do so over a race distance has the potential to over heat and over wear tires to the point of being less beneficial than driving slightly less aggressively.

[@alecmillea4539]

For anyone wondering, this is achieved by slightly over-rotating the rear tires to such a small degree that they drift to the point of achieving the same optimal slip angle that the front tires are doing. This mean the front tires can be travelling straight, relative to the car, and the rear tires are of course straight (unless the car has 4wheel steering) but the car is rotating to such a degree that all four tires are achieving optimal slip angle. This is how the highest cornering forces are achieved. Optimal slip angle on all four tires. Hence why being a top racing driver is so hard. Trying to constantly achieve this balance on the limit of all four tires through all the corners possible. Especially with race tires where the limit is so aggressive as displayed by the graph in the video. Also this is why racing game AI suck. It’s impossibly difficult to achieve especially when accounting for a real track with bumps, curbs and inconsistency of grip depending on any number of variables.

[@israelignaciomirelesmaria3009]

None of you understood

[@llys3742]

@Israel Ignacio Mireles Maria Let's do a little thought experiment. Car A and Car B are driving on ice. Car A turned its steering 5 degrees to the right while Car B kept its steering straight but rotated the whole car 5 degrees to the right. Which car moves right faster? Car A has 5 degrees of slip angle only on the front tires, while Car B has 5 degrees of slip angle on all four tires. Four wheel drift!

[@israelignaciomirelesmaria3009]

@@llys3742 Ok cool,but i still think you didn't understand the video

[@johnwardale6010]

TY. TY. TY. Once again your graphics and style make a confusing subject understandable!

[@rw_yr1352]

"Now if you don't have talent, you can always get a lot of big spoilers" God that was hilarious.

[@DylanL69]

That pic made me laugh

[@jamesofoof1232]

Bloody love your videos so much man, you have so much knowledge that I haven't learnt anywhere else and once again prove that there is always something to be learnt. Keep up the great work.

[@Abdo.28]

I like your Videos

[@Abdo.28]

And make more life examples... i love them

[@mmessner1353]

little correction: 2:20 the graphic is right, allthough the words are a bit misleading. centrifugal force only exists, IF you have enough grip to the ground. if you have bad tyres and drive on ice for example, there is no grip, therefore there is no centripetal/centrifugal force acting anywhere and thats why the car keeps going just 100% straight. a better wording would be: in order to turn a car into a corner, you need centripetal force pulling the car along the curved path. this centripetal force must be delivered by the grip of the tyres: either they provide enough, then its good, or they dont, then the car starts to under/oversteer and eventually and even worse just goes straight like on ice.

[@richmondvalentine9738]

No, you're wrong as well. Centrifugal force NEVER exists apart from in your mind. It's an illusion. The thing that is wrong in his video is not the words that he is saying but the direction of the orange arrow. There is absolutely no force that points out the way from the car like he showed. Actually, the "centrifugal force" arrow continues in a straight line in the same direction as the road that the vehicle CAME FROM. In this case, the orange arrow would point straight up, not to the left

[@mmessner1353]

@@richmondvalentine9738 Boy, i teach physics. you lost me at "NEVER exists" and "illusion". Id recommand you quit skipping classes and go to school. Or read an article about fictitious forces and that they are VERY real. it is the same as the centripetal force, but viewed from a different perspective. they share they same formula, they have the same number but different directions and they are BOTH very real, but depending on where you are, you experience/see either or.

[@hotflashfoto]

My brain now hurts, but it's starting to feel better after your explanation. Thank you!

[@WouterB76]

Bringing car technics educational videos to another level, D4A is doing it.

[@stephenfoster6940]

I have enjoyed your videos very much because you don't shy away from using the underlying engineering and physics when giving a technical explanation, which often contradicts "common sense" or other widely held mistaken views (your video on braking and rotor size was a great example of this). The examples you provide are very good at illustrating concepts and you are an accomplished teacher. However, here's the BUT ... to be technically correct you should not introduce the idea of "Centrifugal Force" - I'm sure that you are aware that this is not a real force but only appears to exist in certain accelerating reference frames such as cars (and, yes, even though your speed, a scalar, might not be changing you are still accelerating, a vector, as you turn a corner). It is completely imaginary. It is an illusion. When cornering, there is no "centrifugal" force pushing you to the outside of a turn. The only force acting to make you turn is Centripetal Force which is deviating the car's motion (Newton's 2nd Law) from its otherwise straight line path due to inertia (Newton's 1st Law). The friction between tyres and the road (just as for braking) provides this net force towards the centre of the circular path/turn otherwise the vehicle would not turn the corner (e.g. if it hits ice or oil on the road it will continue in a straight line and not make the turn). "Cornering Force" = "Centripetal Force". "Cornering Force" does not "fight centrifugal force", it "fights" inertia. It is not "higher than momentum", as you say, because momentum and force are two completely different things. My challenge to you is to make/revise this video using the correct physics from an external reference frame (e.g. that of the road) that doesn't require imaginary forces. I don't wish to be unnecessarily pedantic but your other videos are so good that this one risks undermining that excellent work. Thank you for the videos, they are outstanding.

[@freshrockpapa-e7799]

Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics or you break the second law of Newton. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force and how to account for it in non-inertial frames of reference, it definitely isn't a simplification nor a mathematical trick, but a fundamental piece of how the universe works

[@johnkufeldt3564]

good episode, loved the tire test machines, shows how much abuse tires have to put up with. Yet modern tires are extremely reliable. They have changed so much since the invention of the pnuematic tire. And even since the 1970s when the big switch from bias ply to radials came along.

[@duffieldjunction6243]

My motorsport engineering degree is taught by you more than by my lectures 😆 thank you!

[@daddyalen1726]

It's time to subscribe to this channel this man is a genius

[@Guderian0617]

Centrifugal force does not exist, it's inertia that makes you go in the original direction. But since the car is changing direction, it feels like you are being pushed out.

[@stepside2839]

Haha … I was waiting/watching for someone to point that out As you know … centrifugal force is a fairytale force The correct terminology is Centripetal Force 👍good one

[@drup3376]

@@stepside2839 actually centripetal force is the force that keeps the car going in a curve. So it points opposite the direction you show on your diagram. Otherwise the car would go straight at any point in the curve. Otherwise an excellent video.

[@stepside2839]

@@drup3376 I did not put up any diagram 🤷‍♂️ But, I agree with you.

[@andresluukas1922]

A laughable claim, Mister Bond, perpetuated by overzealous teachers of science. Simply construct Newton's laws in a rotating system and you will see a centrifugal force term appear as plain as day.

[@danboah2501]

🤓🤓🤓🤓🤓

[@piyushgupta4769]

Bro explained all possible possibilities of doubt while explaining it 😅. Just a amazing work by you. Literally feel enlightened by learning deep science behind cornering of car

[@Watchdog_McCoy_5.7x28]

I like to think of the slip angle as the "stretch angle". The upcoming contact patch is being stretched forward each time steering input is given and unstreched when removing steering input.

[@DylanL69]

If it was stretched forward wouldn't that be going straight it's stretched sideways to go that way

[@Watchdog_McCoy_5.7x28]

@@DylanL69 i think of the contact patch as having little arms stretching out and grabbing the road ahead of them. The slip angle (stretch angle) is determined by the steering input and speed, so if the car is going straight then the "little arms" are stretching straight ahead and there is no slip angle. The steering wheel input will cause the arms to reach forward and grab the road ahead at whatever angle is necessary to keep the car following the intended driving line, so long as the grip of the little arms holding onto the road aren't exceeded (centrifugal force) causing the contact patch to lose traction with the road's surface thus spinning out and hitting the wall or ditch... I may be way off base, but that's how I picture it in my head, although this video is a much better explanation in it's entirety.

[@DylanL69]

@@Watchdog_McCoy_5.7x28 what you said makes sense

[@VinnieLeeStudio]

Actually, your explanation is quite easy to follow. Well done! Thank you for this amazing video. I didn't know that the tyres are deforming this way during corners.

[@psychosis7325]

Enjoyed this and would like to see a part 2 expanding on it some more as centrifugal force to us is not really a force at all as we don't experience life in a rotating frame of reference, so while its semi intuitive for understanding part of what is going on at a basic level, I think it is missing all the juicy stuff and you need to look at it from an inertial frame of reference to get a proper intuitive feeling for all thats getting the car around a bend..... Was physics that ultimately lead me into becoming a mechanic and tyre specialist after struggling to grasp everything in an intuitive way 😅 including centrifugal force. Is one of those things like E=MC2 that I wish I just never learned as its basically useless only applying to massive particles that are at rest, well nothing is at rest so might as well have taught me the entire field equations before trying to show me shortcut that only applies in special cases of never. Same for vacuums 😅 if they just talked about relative pressure or something and kept absolute vacuums and and their theoretical nonsense out of things, I'm sure far more people would understand a vacuum cleaner or car engine and start to get a grasp for feel for fluid dynamics and so on.

[@toddwasson3355]

Agreed. The centrifugal force thing is an endless battle which does nothing but confuse everyone as it conjures images of forces "overcoming" other forces and all that nonsense. As soon as somebody uses centrifugal force in a talk about cars you know they haven't a clue what they're on about on the vehicle dynamics end.

[@isodoubIet]

" we don't experience life in a rotating frame of reference" You sure do when you're riding in a car. Centrifugal force very much is a force. Accelerating frames of reference are not "worse", they're not "lesser". They're perfectly valid points of view from which physics can be described, and if you don't include centrifugal forces because they're "fictitious" you'll get it wrong.

[@psychosis7325]

​@@isodoubIet I disagree with that, because centrifugal force is a fictitious force that depends on the choice of the frame of reference and requires a frame rotating around an inertial frame. It is not a physical interaction between the car and the passengers, but a result of the inertia of the rotating object. If we choose an inertial frame of reference that is fixed to the ground, we do not need to account for centrifugal force to describe the motion of the car and the passengers. The net force on them is the sum of the normal force, the gravitational force, the friction force, and the applied forces of the engine, the brakes, and the steering. The applied force of the steering and the engine acts via the frictional force perpendicular to the direction of motion, creating a centripetal force that makes the car and the passengers change their direction and follow the curve of the road. This is a more intuitive and accurate way to explain the motion of the car and the passengers going around a bend, without introducing centrifugal force or a rotating frame which needlessly complicate the subject as much as covering that gravity is also a fictitious force in general relativity would..... Including centrifugal force instantly implies a rotating frame and IMO should be left out totally. I too no doubt made mistakes in what I have said, but I'm just a crippled mechanic and some dude on the interwebs giving my two bits, on how I think I'd make an intuitive guide to slip angle better rather than the one making it. So its not like I really need to get it exact, but you're right to comment in as I didn't really sum up my point as best as I probably could, mind you when I do that, the responses are usually "TLDR".

[@isodoubIet]

@@psychosis7325 " I disagree with that, because centrifugal force is a fictitious force that depends on the choice of the frame of reference " So is gravity. Some people will make the argument that gravity isn't a real force but that's getting pretty silly at that point. "If we choose an inertial frame of reference that is fixed to the ground, we do not need to account for centrifugal force to describe the motion of the car and the passengers." Yes, but so what? Nothing's _forcing_ you to use an inertial frame of reference. You analyze a problem in whatever frame of reference that problem is _simplest._ And no, it doesn't automatically follow that fewer forces = simplest. " I too no doubt made mistakes in what I have said " Physics-wise what you said is just fine for this discussion. I only take issue with the blanket condemnation of centrifugal forces as automatically more complicated. For example, when you take a corner, the weight will shift towards the outer wheels, right? You could describe it from the inertial frame and consider the torque from the wheels, but I'd argue it's much simpler to consider centrifugal force is pushing the car outward. That said, the explanation in this video was indeed totally wrong and I think your way would've been much better.

[@relaxingmusic7301]

@@isodoubIetgravity is a force now ? it's an acceleration not a force at all, and yes centrifugal force is a fictive force

[@hyena8385]

Please take this as a compliment! - you make it SO clear and explain it SO well that my ten year old is perfectly able to not only understand it but enjoy watching! I thought I had to further add: Making these sorts of vids are a kind of unsung heroism to me - you never know who you would have inspired to be a next gen engineer, scientist and so on!

[@toddwasson3355]

Erase centrifugal force from your minds, folks. It doesn't exist and just confuses the picture, giving the impression that there are two forces fighting each other which simply isn't the case. All that exists is the tire force. There's no other force to "overcome." This irritates me because I've had to spend so much time unscrambling the brains of programmers trying to model tires + vehicle dynamics who unfortunately have had this type of nonsense drilled into their heads by KZbinrs I've lost track of it all. The slip angle stuff has nothing to do with contact elements being dropped at the front of the patch laterally progressively further as the yaw changes in a circular path as illustrated in the video by laying hands down one at a time at increasing angles on a curve. That's not what's going on. You can have a slip angle without yawing the wheel. It just needs to roll in one direction while pointing in another. I.e., there just needs to be a slip angle, it doesn't matter if the yaw rate is 0 or not. Tire test rigs measure lateral force vs slip angle tests using a belt, some of which is shown in the video. The tire is not following a circular path in those tests. If a wheel is facing north while moving to the north-west, the slip angle is 45 degrees, period. It doesn't matter if it's following a curved path where the wheel's heading is changing or not. All this means is the portion of the tread rubber stuck to the ground spends at least some time moving at a 45 degree angle to the rim. But even that isn't always true: The tire could be locked while sliding at a 45 degree angle. That too is a 45 degree slip angle. So it's not even necessary for new tread elements to enter the contact. It's just an angle, folks. Nothing else. A better mental model is the front contact position is at zero lateral distortion when it lays down on the ground. At that point it simply sticks there under the load of the vehicle. Meanwhile, when cornering, the rim is moving laterally relative to that (more or less) stationary rubber, so as a given bit of the tire contact travels to the rear, it is stretched further laterally with distance. Eventually as the load toward the rear of the contact patch reduces toward (and eventually all the way to) zero, that part of the patch slips back. That lateral stretching in the sticking region produces the lateral force which accelerates the car sideways just like a stiff rubber band would. There is no centrifugal force, the lateral force isn't "fighting against" anything at all. If those two supposed forces were equal and opposite as described, the net force would be 0 and the car wouldn't turn at all. That's a slightly simplified picture, but it's a good description and leads to good mathematical models for simulation. That angle between the two directions is called "slip angle" regardless of what the tire is doing, whether it's tracking a turn at 6-10 degrees or sliding all the way out to 90. Drifting, not drifting, it doesn't matter. Tire force is largely a function of that slip angle. It climbs to a maximum at a few degrees (different for every tire, load, inflation pressure, etc..) then generally flattens off, sometimes decreasing a little with further increases in slip angle. Google "lateral force vs slip angle" for charts and measurements of this on different tires. The point raised at about 7:30 in the video that 0 slip angle = 0 cornering force is also not correct. I wouldn't pick on that too much, it's generally pretty close to 0 on street tires and is an ok explanation for laymen which the vid seems geared toward, but it's not really right. There is always some shift at the origin around 0 slip angle, especially if there's camber. Google "camber thrust." Part of the reason your car's alignment is not 0 degrees toe is because of the presence of some lateral force at 0 slip angle. In fact one of the NASCAR tires in recent years produced as much as 50% of peak lateral force at 0 slip angle. That's unusual and is the most extreme case I'm aware of, but tires can in fact be engineered that way. For more information, search "ply steer" and "conicity." When NASCAR people talk about "building camber into the tire" with different sidewall stiffness at each shoulder, this is what they're referring to. The notion that it'd be impossible to have any lateral force with a perfectly rigid tire is also incorrect. Granted, stone tires would be awful to drive on, but they most certainly would produce some force with imperceptibly small slip angle just as a block of stone does when you push it. Everything deflects under load. Everything.

[@toddwasson3355]

Part 2: Cornering force vs friction force at around 9:00: I'll show some lenience because I understand that was meant to be a simplified explanation, but I think it really just adds to the confusion. It's a bunch of unnecessary hand waving. The fact of the matter is that the friction force and the cornering force are exactly the same value. They will always equal each other, so there's no point in trying to add yet another force into the picture (like some do with centrifugal force) to "clarify" what's happening by adding another non-existent equal and opposite force on the vehicle into the picture. If by "friction force" you have in mind the maximum possible cornering force, then I would just say that instead of adding a new force and talking about some difference between a resisting force and an active force as though they're different things where one "generates movement" and the other doesn't. No. A force is a force, period. It'd be better to show your lateral force vs slip angle diagram near the beginning of the video (using real measurements instead of the ridiculous illustrations, more on that later), point to the top of the curve and say "this is max lateral force. This goes up and down depending on available friction between the rubber and the road. The higher it is, the faster you can go around the turn." To say "friction force" can not "generate movement" is again overcomplicating and/or misunderstanding what a force is. A force is simply that which causes acceleration. Newton's law (F=MA) rearranged: acceleration = force / mass That's all a force is: It's the thing that causes acceleration. "Generating movement" doesn't mean anything. If your car flips over onto it's roof, the friction force most certainly accelerates the vehicle toward a stop. Is that "generating movement" or what? Again, just like trying to bring centrifugal force into the picture, it's an unnecessary complication. This stuff is a lot simpler than people are making it out to be. What's really happening is both forces exist simultaneously, but from a vehicle dynamics modeling perspective it is generally more useful and practical to think of (and program) the system something like this: 1. Start with a slip angle. It's just an angle between a velocity vector and a direction vector. That shouldn't need a 6 minute explanation tbh.. People will understand it better if it's simplified to what it actually is and nothing else. 2. Because there is some friction available at the tire in the presence of slip angle, the tire distorts as the rubber moves through the contact. The rubber stretches which induces a cornering force which is possible because friction force increases the same amount. And because acceleration = force / mass, the force acts to accelerate the car sideways. And again, the very definition of the word "angle" means the tire does not need to be following a curved path for this to happen. A simple gust of wind will do it. A non-circular path is visible in the tire machine tests in the video. And angle is just an angle, and a force is just a force. That's about as complicated as it is. Not very. At 12:10 you show street tire vs racing tires. Couple things: 1. Racing tires generally peak at a smaller slip angle than road tires, not the other way around. A better illustration would be to have the racing tire increase on a much steeper slope than the street tire and peak at a smaller angle. 2. 5-6 degrees is more typical of a racing tire than a street tire. Street tires are usually a bit more than that. 3. The drop off after the peak in the illustration is fantastically exaggerated. In no circumstances do they peak at 6-8 degrees and then go to 20-30% force at 13-14 degrees like shown at 13:00, though. This is exactly the kind of nonsense that lead publicly available racing sims to be ridiculously hard to control and drive nothing like a real car when sliding. There's plenty of public tire data out there, why not Google and throw out the illustrations?Most street tires barely have any fall off at all after the peak, if any. I've seen tests all the way out to 90 degrees that had none whatsoever. With racing tires, anything can happen though. Some racing tires will stay pretty close to flat after the peak, other tires will hit a peak and then very gently continue rising for awhile before falling off. Some will rise and gently drop. They can even change over the course of the run depending on tire temperature and so forth. Generally it is a safe bet that the racing tire will be more peaky though. Some of this video I'd give a thumbs up on, but unfortunately there's an awful lot of nonsense here too. The biggest problem is the centrifugal force stuff. A tire force produces an acceleration. f= ma, period. There's nothing to "overcome." Please, everyone, stop talking about centrifugal force. The physics are much simpler than KZbinrs are making all this out to be.

[@freshrockpapa-e7799]

@@toddwasson3355 Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force, it definitely isn't a simplification nor a mathematical trick.

[@windhelmguard5295]

one huge factor in driving around a corner quickly and efficiently is the automotive differential, which allows all driving wheels to rotate at different speeds. this plays a huge role in how a car behaves when cornering so i found it important to bring it up.

[@gaborb]

then its also important to note that the open differential you referring to is a drawback to drive around a corner quickly. just search for limited slip differential

[@RobManser77]

@@gaborb We need to be very careful about our wording here. Windhelm is correct, the open differential is an advantage to driving around a corner quickly, because it allows the driven wheels to rotate freely at different speeds. What you should say in your reply is that the open differential can be a drawback to traction when *accelerating out of* a corner (from apex to exit), not when driving around a corner (i.e. all the way from turn in to exit). With a limited slip differential, there is resistance to the driven wheels taking on different speeds and that can actually result in poorer cornering performance, depending on how the LSD is tuned. Understeer can occur on corner entry if the wheels are reluctant to start to turn at different speeds on coast. On corner exit, the same understeer can occur, or if traction is breached, oversteer can occur, often unpredictably as you transition from open to limited slip behaviour (it's rarely smooth!). I've raced and tested a number of cars with open diffs (Caterham, Metro, an older Formula Renault, and various Formula Fords) and two with LSDs (my Formula Renault 2.0, and my current MGB V8). I've also driven a number of cars on track non-competitively with and without LSDs. In my opinion, the open diff cars drive much more naturally and fluidly through all stages of corners, and breaking traction is dealt with predictably and gradually. LSDs can change handling somewhat, hindering cornering, and can be a bit grabby when losing traction, although there's no denying that they're ultimately faster if you can tune them correctly and drive sympathetically to them. Ultimately I'd take an LSD in the wet if well tuned, and despite the fancy diffs in my racing cars probably the nicest I've driven have been on BMW M road cars. In the dry if not too traction limited though, I'd rather have an open diff, for example an Elise or low/mid powered Caterham or Formula Ford.

[@gaborb]

@@RobManser77 yes the wording is important but you are saying the same " there's no denying that they're ultimately faster". You are adding more details which is of course also useful and important. i wonder why you did not mentioned the 1 way lsd what is apparently your favourite. i also like the BMW M road cars (not the old ones) with the electronically controllable differential. Those are really tuned well and does what you asks for.

[@SriyanGaming]

cornering force is just friction - centrifugal force is just inertia. You should clarify these things please in your video

[@xaviergonzalez5828]

Bro, what a masterpiece video! When I was an automotive engineering student, those concepts had blown up my mind. Only I can say thank you for taking your time to explain this difficult topic. Hats off! English is not my mother tongue, but I got you perfectly!

[@SHDW-nf2ki]

Perhaps a better way to think of the "difference' between cornering force and friction is that there isn't one at all. Friction is a singular force, while cornering force is a combination of multiple forces creating by the deflection of the tire against the road surface that works to overcome the momentum of the car and centrifugal force

[@mattholden5]

Wow! Your vids are usually enormously insightful, thought provoking, and loaded with subtle opportunities for a chuckle. This one explained in a few minutes all the things I misunderstood / didn't have a working mental model for regarding understeer/oversteer (and how to affect them with purpose). Well done, sir.

[@jtocher685]

Yikes! I get what you are trying to do here but I wish you wouldn't have used 'centrifugal' force, which ends up sending people in the wrong direction, pardon the pun. Centripetal force is what is required to turn a corner as I'm sure you know. Force(c) = Mass x (Velocity(squared) / TurnRadius). Centripetal Force also keeps the earth in orbit around the sun and the moon in orbit around the earth. In these cases the Force(c) is provided by the gravitational attraction between the objects and in the case of the car it's provided by the tires running at slip angles. In the absence of Centripetal force an object in motion would continue to move in a straight line. Although 'centrifugal force' is frequently used in the way you describe, it's not a real force...it's a way of looking at things from the perspective of an object which is being accelerated. In your example, the car and the people inside. The people inside may feel like they are being thrown outward into the door by some force but they are not. They are subject to centripetal force in the direction of the center of the turn. That force is applied by the seat, seatbelts, door, steering wheel, grab handle etc...whatever the person is in contact with in the car. If you're going to use 'centrifugal force' as an aid to understanding (which I don't think works anyway), it would NOT be smaller than the 'cornering force' either. When used for explanatory purposes, centrifugal force must be equal in magnitude and opposite in direction to centripetal force. Great shots of suspension and tires in action! The amount of distortion in the sidewalls really illustrates your best points about not directly controlling the contact patch!

[@freshrockpapa-e7799]

Centrifugal force does exist and is just as real as the concept of inertia. If you're inside a non-inertial frame of reference (like, inside a car taking a corner) you do need to take into account centrifugal force and coriolis force to do physics. If you grab any college textbook on classic physics you'll see it's full of mentions of centrifugal force, it definitely isn't a simplification nor a mathematical trick.

[@jtocher685]

@@freshrockpapa-e7799 Centrifugal force is always described as a 'fictitious' or 'apparent' force. It is used as a means to explain the 'sensation' one gets when subjected to acceleration. When you refer to a classic physics textbook, are you talking about one from the 18th century? en.wikipedia.org/wiki/Centrifugal_force

[@freshrockpapa-e7799]

@@jtocher685 No, I'm talking about modern college textbooks. Don't confuse "fictitious" and "apparent" for "not real". Again, just go to the webpage of the most prestigious college you know, see the curriculum of Newtonian physics, classical physics, or simply mechanics or dynamics, and pick at random a book from the bibliography. You'll see it is full of exercises involving centrifugal acceleration in non-inertial frames of references, because it's just as real and you need to take it into account while doing your calculations, otherwise the second law of Newton breaks.

[@jtocher685]

@@freshrockpapa-e7799 Lol, pretty sure the definition of 'fictitious' is 'not real'. Anyway, yes you can do computations within a non-inertial frame of reference and engineers will do it when it's convenient but unless you're very careful not to confuse real and apparent/fictitious forces you are bound to make mistakes. If you do make a mistake like that, something will break alright...but it won't be Newton's 2nd Law!

[@freshrockpapa-e7799]

@@jtocher685 You can't take the definition of a word used in common language and assume that it has the same meaning in science. That's how you would think that imaginary numbers are less "real" than the real numbers. What I'm telling you is that observing reality from a non-inertial frame of reference is just as real as observing it from an inertial frame of reference. There's no reason to assume either is in any way superior or more true than the other.

[@douglasboyle6544]

I know a lot about a lot of things but I always learn something new from your videos and in this case, I learned A LOT! You were right, I thought I knew but I didn't 🤣

[@Alobger]

I’m very uncomfortable with using centrifugal force to explain cornering. It muddles up whether you’re observing from inside or outside the car.

[@gort8203]

Agreed. "Centrifugal force" is what the occupant of the car feels as he is pressed against the side of the side of the car/seat that is accelerating him in the direction of the turn. Centripetal force is what pulls the car toward the center of its turn radius. It is a continuous lateral acceleration.

[@OmGiTsMeTaStY]

Why would it matter where we are observing? Centrifugal force is acting upon the car no matter where you're observing from.

[@Alobger]

@@OmGiTsMeTaStY Centrifugal force is what the occupants within the car think they experience excerpting on the car’s sides - it doesn’t exist. They are actually experiencing a centripetal force from the car’s sides making them go round the corner.

[@horrorhotel46290]

Yes, and a vacuum does not suck, and from the point of view of a photon, the universe is time- and distanceless. The entire video becomes so much clearer and makes so much more sense to everyone who isn't interested in physics specifically by introducing this distinction. It really is a good thing he explained things your way - makes the thing he is trying to explain way more accessible to everyone ❤

[@freshrockpapa-e7799]

@@OmGiTsMeTaStY Wrong. Centrifugal force can only be seen and deduced if you're observing things from a non-inertial frame of reference. Please don't make things up to confuse people.

[@tryggmundur1188]

Slip angle is a common topic of debate in the sim racing world. Most people focus too much on achieving this mythical "4-wheel drift", when the main key to gaining speed is correct tyre setup and line choices. Slip angle is something that is only exploited at the higher levels because their tyre setup and racing lines they take allow them to stay in that peak slip angle region. Analysing the data from tyre testing facilities is also tricky. The road surface they test the tyres on is usually a big belt of sand paper; which is obviously very different to asphalt. Vehicle dynamics is my favorite area of engineering. It's an incredibly deep rabbit-hole

[@gort8203]

The low slip angles of modern tires may make the 4-wheel drift seem mythical, but it is very real. And with skinny bias ply tires it can be done at quite a dramatic angle. That, and the perfect rev-matched downshift while trail braking, are the two most rewarding experiences I've had while driving an automobile.

[@jackshaw1047]

Genuinely great video, glad the algorithm gave it to me

[@robertrotterdam9]

Thank you. You are a GREAT teacher!

[@Sowhat-u6f]

Great video! Some of this I knew but the video brought it all together and especially the concept corning force. I suspect it may also be good to contemplate that, for at least everyday driving, we do not instantaneously whip the steering wheel to the maximum needed amount to traverse the given corner. Rather, over the expanse of a fraction of a second or two, the steering wheel is repositioned relatively gently and sequentially to help the tires not to break from the road surface. Of course, this mention is subordinate to the core explanation provided in this video.

[@Clumrat]

Everything clicked with this video and I've learned so much, it came out right when I needed it. Excellent video.

[@DarylCook63]

Using hands to represent the tire contact patch helped me to finger out this phenomenon…so, thumbs up!

[@apersunthathasaridiculousl1890]

Didn’t know you could learn something completely new and completely understand it right away XD This guy is great!

[@Benautodesign]

Very well put ! A lot of racing drivers, even good ones do not understand this clearly.

[@trm4life]

Well explained. I love this channel because this guy wants everyone to understand, and isn't afraid to do a little "over explanation" to make sure everyone gets it!

[@battlearenatoshinden]

Wonderfully informative video.

[@teilanittv]

My mind is blown. I was skeptical at first but you have broken it down so well I didnt even have to make it 5 minutes before I understood. Makes perfects sense.

[@jithendrapathiraja6444]

Thank you Mitchel Stark. U saved my life

[@Pooneil1984]

Simplifying complex physics to become understandable to non-physics people is very difficult. As difficult as taking a corner and the limit of the slip angle. I appreciate the skill here.

[@adebowalekonstantinov404]

You made it seem like this video is going to be torture, but it was actually pretty enjoyable and understandable😉! Also I'm just about to subscribe with 999K subscribers, I hope I'm the 1 millionth! and congrats of course!

[@fifossucrilhos]

This is a good intro to tyre dynamics. There are some really good papers from the 1960s which simplify the tyre mechanics into a Tire Brush Model. These were later superseded by empirical models like the magic formula from HB Pacejka. But, are still great for a base understanding.