Torque and Horsepower Explained! | The Shop Manual

[@RevZilla]

Get the latest moto news and bike reviews at Common Tread rvz.la/3SiLCEB

[@Lex4122]

Hey Team, thx for another awesome video :) Would it maybe possible to get a video from Ari´s Shop Manual, of him doing an upside-down fork rebuild? I know there is an video during his old MM times, but thats 8 years old and was about an right-side-up one. Greetings an have a good one folks

[@lezzbmm]

i’m sure y’all have muted me but this video rly needs a rewrite if u want to avoid misinformation and actually elucidate the difference btwn torque and power for bikers who don’t know.. power = acceleration torque ≠ acceleration torque = where the power band is in the rpm power tells u how fast u can accelerate torque tells u what rpm range yr power band is at.. (a 200ftlb 100hp bike had a much lower redline than a 60 ftlb 100hp bike for example,, but w the perfect transmission they’ll have the same acceleration..)

[@v.onthemove]

This was the explanation i was looking for. I knew the diff...but only at a surface level. The crank motion animation & explanation with the two different motorcycles really helped.

[@BS32768]

Yes - holding the piston-con rod and the crank pin made the difference for me too. Have seen many videos on hp vs torque and the force x distance equation but somehow that visual made it click.

[@OrangeGenerator]

same was very helpful!

[@yogeshavl]

Indeed

[@sepg5084]

Torque is just a force. I think the concept of force is quite intuitive. Power is the one that is less intuitive. In layman's terms, a powerful muscle can exert a lot of force. But when you say a powerful engine can exert a lot of torque, it can get confusing because of the power and torque numbers/curves in the specs/dyno sheets. The torque can climb down while the power still goes up, but all is relative to the rpm. In describing engines, compared to describing muscles, the term Power is more technical. A force causing motion in the direction of that force, is producing work. The higher the rate that you can do that "work", the higher is your measured power. Torque is the rotational force produced by the engine's combustion, causing the crank to rotate (revolves). The rate of crank rotation is in revolutions per minute. The higher the torque that your engine is exerting at a certain rpm, then the higher the power will be at that rpm. Suddenly, the term "work" here is not specifically mentioned anymore. If your engine crank is rotating at a rate 6500 rpm with a force (torque) of 500 lb. ft. behind it, then it is producing 619 hp. The terms that are constantly there is the torque (force) and the revolutions (motion) per minute (rate). Power is kind of just a "calculated" result.

[@chriscurlett4548]

“How rapidly the torque is applied” made a lot of sense to me.

[@JS-ov9jb]

The wrench into gear graphic was spectacular.

[@Frilabird]

Real

[@JonTheOutdoorsman]

Of all the videos I've seen explaining torque and horsepower, this is the best one ! Way to go Revzilla, another great video!

[@kindopaceweeb3028]

A wise man once said "Horsepower is how fast you can crash into a wall and Torque is how many walls you take with you."

[@ZacharyBraxton-kl5bs]

Classic. Saying.

[@doomman700]

Worst analogy ever.

[@nogginbonker76]

😂😂😂😂 what an awesome analogy.

[@nogginbonker76]

@@doomman700how’s it wrong? I’ll wait.

[@doomman700]

@@nogginbonker76how is it wrong, start with torque is a twisting motion not push. Then the fact that momentum will be what carries that wall which means speed and Hp will push it farther. Need more?

[@alli333o]

04:43 you're wrong at this point. Acceleration also is a fuction of power. Both top speed and acceleration are very much depending on power, as long as you have some sort of torque converter (=transmission).

[@motominded5275]

came here to say same and if I heard the wall analogy I was going to lose it

[@mr.b3168]

I always knew what it was. But the analogy of the runner is a good one. The actual step pushing off the ground is the measure of torque, and HP measures the distance with multiple of those steps

[@rigididiot]

It is a nice but completely useless analogy, because the torque as in the subject of this video is crankshaft torque, which is one of the most useless engine parameters, unless boasting and bragging are a virtue. Crankshaft torque cannot be compared to the runners "push-off" because bikes and cars, unlike runners, have gearboxes. Crankshaft torque is TOTALLY meaningless. At best, the SHAPE of the torque curve matters, but only a bit, and only for mediocre drivers that do not know how to use a gearbox (and I know that because I am one, hence my preference for older big twin sportsbikes like the 2-valve Duc's). The best practical example for the utter irrelevance of engine torque can be found in Moto Grand Prix racing in the 1960's and '70's: Despite fourstrokes being "torquey" and riderfriendly with a wide powerband, pulling like a freighttrain, opposed to twostrokes being peakey and high revving, narrow powerband and not all that much torque compared to the 4-strokes, without a single exception ALL manufacturers went with the 2-stroke for the simple reason that it is horsepower that wins races. Not torque. Even Soichiro Honda, who absolutely HATED twostrokes and tried to keep racing a fourstroke with the NR series, knew this (the NR was intended to extract 2-stroke horsepower from a 4-stroke engine). Honda had to cave and also changed to 2-stroke. Quite succesfully, I might add.

[@big_daddo92]

Ari does such a great job of breaking it down for the viewers! Keep these awesome videos coming Revzilla!!!

[@maximusDAbiker]

I always knew the difference in terms of applicability, but the actual physics behind it never clicked until now! They aren’t 2 different measurements, Torque is a variable within horsepower. You finally helped it click, thank you!

[@rahulvinodpatil]

It's like money. USD 50000 is a nice amount but meaningless without time, is it per week, per month, per annum, over a lifetime? Similarly, torque is timeless, horsepower is torque over time.

[@gorillamoto5329]

How did you know the difference in application, but not understand the physics? Cart before the horse.

[@sawarebel]

Well,if you ride a v twin and a sportbike i would say its impossible not to feel the difference@@gorillamoto5329

[@paulneedham9885]

​@@gorillamoto5329easy, if someone tells you torque is strength and Horsepower is Power then you now know the difference in application but you still might not know the physics behind it. We all know what things do but don't know how many things do it.

[@freebehindbars8654]

⁠@@paulneedham9885torque is strength, Horsepower is power? 😂 Watch the video again. In simple terms, horsepower is torque over time.

[@dragoclarke9497]

Thank you. I have just spent 40 minutes over breakfast flicking through rubbish videos suggested by KZbin only to give up and see if my favourite channel has posted anything new. Yes! Sanity returned, I can now enjoy the rest of my day suitably educated and knowing there are some great videos on KZbin, just that most of them are from Revzilla.

[@Edgar4T007]

Torque is strength, horsepower is speed 👍

[@drienkm]

Half true. Power is speed and strength (speed x strength).

[@SlyNine]

No, because the gear box. You can gear for more torque. HP will dictate how much torque there is at the wheels.

[@peterdeptula3628]

I've heard this explained so many ways over the years. This has got to be one of the cleanest descriptions. Good explanation and analogies. Nice job!

[@tristanbased-af2159]

I have that 2024 ZX6R in that color scheme! love it

[@RussellAutosport]

What clears up all the confusion (to me at least) is gearing. Using gearing (both the ratios in the transmission and the sprockets), we can change the torque to whatever we want it to be. 100 hp = 100 ft lb * 5252 rpm 100 hp = 200 ft lb * 2626 rpm 100 hp = 50 ft lb * 10504 rpm So say at 50 mph, both the Harley and the Kawasaki will have their rear wheel spin at the SAME rpm. Say that speed is 525.2 rpm for simplicity. At this point it’s clear that the Kawasaki is actually putting more WHEEL TORQUE to the ground than the Harley, regardless of what the crankshaft torque is. 116 hp = 1160 ft lb * 525.2 rpm 83 hp = 830 ft lb * 525.2 rpm

[@victorugo3875]

116hp is the Kawasaki's peak horsepower, which occurs at much higher revs. If they were both revving at 5252rpm, the Kawasaki would likely be putting less wheel torque to the ground.

[@RussellAutosport]

@@victorugo3875 yes but where the peak engine revs occur don’t really matter because with a transmission we can gear it however we want. As long as the engine is in the power band (I.e. don’t try lugging a 636 engine at 4k rpm) it is always advantageous to have more power

[@victorugo3875]

@@RussellAutosport you're right. Thanks for clearing up.

[@joepelletier5381]

Love the video, some great explanations, I do worry that some people will hear "torque equals stronger acceleration and horsepower means higher top speed" and miss the caveat that the transmission makes the torque somewhat irrelevant.

[@pleasedontwatchthese9593]

Yeah that line is not true. A bike acclrates faster in its powerband, it's weight and gear says the same. The only think it change was the amount of horsepower that was created.

[@joepelletier5381]

@@pleasedontwatchthese9593 I get the simplification he's going for and I'm positive he knows the intricacies. It's difficult to tell a KZbin audience to integrate the horsepower chart across the range of the intended powerband to determine average acceleration. The sentence just seemed like a misleading sound bite when later people take it out of context.

[@pleasedontwatchthese9593]

​@@joepelletier5381 I agree with you. My main point is it should have been left out because as you point out it will be misleading

[@LTVoyager]

True. Given perfect gearing, the engine that makes the most horsepower will also make the most torque. In real life though we have no perfect gearing so in many cases an engine that makes greater maximum torque is more useful.

[@joepelletier5381]

@@LTVoyager I think my point is that this is only true (that we should compare just torques) if both bikes have the same redline and I'm afraid that wasn't clear in the video.

[@NarcissisticAbuseHealing]

This is the best explanation I have heard of the difference. And how they relate to each other.

[@Xxnate500]

I think this is truly one of the best explanations on the Internet. I’ve watched a lot of videos on horsepower versus torque and I’ve never understood it until now.

[@pleasedontwatchthese9593]

4:45 This video was close to being corrected. The acceleration with same tourqe comment is wrong. A bike in its *power* band accelerates faster than when its not and its the same bike with the same weight in the same gear.

[@rahulvinodpatil]

A bike in its power makes more torque too, than remaining part of the rev range. So he's not wrong.

[@toddguthrie8081]

Do you even know what power band is

[@wetsock3265]

yeah bro, he forgot about the powerband in 100+ year old equation 😭😭

[@SAZIZMUSIC]

Very clear explanation. For a newbie like me in the bike world it was indeed a very concise easy to understand video. Thank you very much.

[@Gnerko123]

Torque is how many revs you need to go fast, accelerate fast, pull a load etc. (do work). Power is how much work you can do. For acceleration, more power yields more acceleration, nit necessarily torque. Power is energy output of the engine per unit time. To accelerate faster, you need to add more kinetic energy per unit time, thus you need more power, nit necessarily torque. Half the torque at four times the rpm accelerates the vehicle twice as fast at a given speed (i.e. adjusting gearing to maintain the same speed in both scenarios), because wheel power is double. Wheel torque is also double, as the transmission ratio differs by a factor of 4 while engine torque only differs by a factor 0,5.

[@sdmascar8905]

best explanation i have ever heard or seen on the internet.

[@rezkyputra5239]

As a scientist who rides every day, Ari using freedom units - ONE POUND OF FORCE - actually hurts my brain. I guess Ryan F9 (whos also a physicist) would agree, great video as always, tho!

[@Shackalacka23]

This has got to be the clearest explanation I've ever heard. Thank you man. You are a treasure

[@RacingRalphEVO]

4:45 - that is not correct actually. More power means faster acceleration, period. But the assumption that if you put these engines with a fixed, 1x1 gear ratio into equal weight bikes, the harley engine will accelerate faster (initially) is right. Not because it makes more torque. It’s because from a standstill, it has *more power*. You see, when an engine makes higher peak torque it often implies that torque is high already low within the revrange, thus it produces decent amount of *power* from the get go. At the end of the day, the peak torque figure is just a simplified indication, how the *power* curve probably looks like. But if you want to understand how fast a bike/car accelerates, the power curve is all that matters.

[@pleasedontwatchthese9593]

I agree, 101 pennies is worth more tgan 1 dollar. It does not matter if each penny is worth less.

[@currycel470]

Usually peak rpm number is good indicator of how power and torque graph might look like. Higher rpm = worse torque curve.

[@Wintersdark]

​@@currycel470usually, but not always, and the problem here is this leads to so many misunderstandings. Just look through the comments to see how many wildly wrong explanations and analogies are here (how fast you hit the wall, how far you take the wall with you, etc). The only actual relevant value to a rider is the whole HP curve, because power is a function of torque and time.

[@d.michaelpratt5987]

Just an excellent explanation of a topic that seems simple but can actually be quite tricky to understand. The young man speaks clearly at a moderate speed, gives a clear explanation, and doesn’t see the need for loud, pounding music playing while he talks. And the video is not overly long. At last, I understand why an engine with a longer stroke makes more torque, other things being equal, than an engine with a shorter stroke.

[@mhoeij]

There's no real math in the 5250 number. These weird numbers are the price to pay if you use US units. In metric units, these numbers are simply 1.

[@KellerFkinRyan]

I mean, conversion is still math. and in my eyes, all math is "real math"

[@arjankroonen4319]

Spoilers! One day the US will switch over to metric and there will be much rejoicing...

[@marcoperez1794]

If you're using metric units you still need to use a conversion factor. It's not 5252, but it's not 1.0 either. The factor depends on the metric power units being used (e.g. Pferdstarke or kilowatts) and the metric torque units being used (newton metres, kilogram metres, etc....).

[@mhoeij]

@@marcoperez1794 horsepower is not a metric unit

[@drienkm]

@@arjankroonen4319 US Aerospace industry and FAA be like, "Oh, everyone else is ready to switch? Okay just a sec. We have about 80 years of test-based industry standards and regulations to re-do... without a war or... the commercial promise of the jet age for motivation".

[@vtecbanger3180]

You did this explanation perfectly. No other video needed for this topic.

[@dasboseimbusch7079]

4:51 And that's extremly important! A transmission can manipultate torque and rotational speed but not the power. n1 * T1 = n2 * T2. So a bike with more horsepower will always accelerate faster if the gearing is right.

[@ddavexn]

I've listened to so many videos explaining torque and horsepower, but none have come close to this one in how easy you made it to understand. Thank you so much for simplifying your explanation so my old brain can finally understand it.

[@brinkipinki]

I think you could've put more of an emphasis on the importance of transmission in regards to torque and acceleration. What accelerates a vehicle is not engine-torque, it's wheel-torque which is extremely dependant on the transmission, while power is constant (minus friction losses) between engine and wheel. This means comparing the torque of different bikes is pretty much useless and really doesn't tell you anything about acceleration potential or speed. Still good video, and not wrong anywhere, which is better than the vast majority of videos talking about this topic :D

[@philsheard832]

Awesome explainer. Useful to me and I've been riding over a decade and driving cars for longer.

[@MotoDude1967]

Best torque/horsepower explanation I've seen, thanks!

[@chiefordnance]

My 2006 Harley build dyno'd at 112HP and 106FT TRQ sold it in 2013. 😮

[@jamesschaffer5504]

Another youtube torque vs. horsepower video? And yet this is a clear and entertaining explanation.

[@rohitsinha1991]

When we are in a higher gear at low speed and try to accelerate, the bike may stall or turn off due to insufficient torque. That's why more torque is necessary in the Commuter / Cruise bikes.

[@thenimp]

That break down with the different runners is the best explanation I have seen for this. I am mad that I never made such a simple connection for explaining this to other people. lol

[@chill_will9816]

But it's a bad analogy. The difference between you or I and an Olympic runner isn't the strides per minute, it's how much power if applied per stride. In the case of a runner VS a linebacker it's just a power to weight/ aero thing.

[@jamescampbell4334]

Torque for the street, horsepower for the track.

[@ParasChaudhary21]

I can say that it's the one of the best video educating with simple and easy examples for torque and horse power, thanks 😊

[@Ledface117]

Everything is great except the end. Horsepower is the POWER that pushes you in the seat. What you feel when you open the throttle is POWER.

[@multi21racing]

Yeah. It was a bit disappointing that the after the good explanation, everything got dumbed down back again to that redneck reasoning. If you put a different gearbox into that Harley, it can reach exactly the same top speed as any other sportbike with the same peak power (ignoring aerodynamics for a moment).

[@biocta]

Exactly, having lots of torque simply allows you to generate power at a low rpm which makes it feel more instantaneous. If you keep your sport bike wound up to 12,000 rpm it would feel just as quick on the throttle.

[@MyShrijan]

This is the best explanation video i have ever seen regarding torque and horsepower.

[@SoybeanAK]

Engineering Explained has a great video on the units and math that derive 5250 in that equation!

[@BahWeepGranahWeepNiniBong]

EE Jason is brilliant👍

[@Purpillhayes99]

Do you know how many years I’ve been trying to figure THis out? . . . And I’m a car guy! Thank you, everyone who had a part putting this video together!

[@tonyboughman8050]

Best explanation I've seen. My dad tried when I was a little kid but he only offered "torque is what you feel."

[@randomcarguy2543]

My Harley out here with 120ft/lbs and 120hp on 91 💪🏻. They can actually be pretty darn quick if u don’t just have a stock street glide, and even then I’ve seen them rip pretty hard

[@brucepenich1012]

That was the best explanation of horse power and torque that I have seen on the internet. Great job. Thank you. Also, your transmission / wrench explanation was very good.

[@tabou1]

At last a clear and easy to understand explanation. I cant thank you enough for this video, which I'll bookmark and learn by heart!

[@pleasedontwatchthese9593]

This is a great video, thank you

[@usmangani7395]

A wise man once said, torque is mike tyson and horsepower is bruce lee.

[@BenjaminFamili]

I see where you're coming from, but I have a different perspective. The comparison between Bruce Lee and Mike Tyson is more about the type of engine and transmission rather than just torque and horsepower. In this context, the force relates to acceleration. Bruce Lee might have the same punch force as Mike Tyson, making them more comparable in terms of the force they generate, rather than just categorizing one as torque and the other as horsepower.

[@amam231]

I’m a physics major and I gotta say, you have explained this absolutely beautifully. Thanks!

[@kennymilton7457]

The number 5250 is usually the rpm where hp and tq typically intersect, if I'm not mistaken

[@sepg5084]

Yes, and that's the specific rpm because of the units chosen. International units graph differently.

[@chestercalloway3812]

It’s technically 5,252.

[@drienkm]

In certain units. yes. Understand that there is nothing physically significant about where those two lines cross. It would be like plotting your height in inches against your age in years; your French friends wouldn't come to your line-crossing party.

[@rajnishrao]

This is by far the most amazing explanation of difference between Torque and Horsepower. Thank you.

[@kokobeatz7222]

Best Moto channel on KZbin.

[@NewHappyMe]

Over Fortnine?? no way.

[@kokobeatz7222]

Fortnine is alright, but he’s not revzilla. Zach and Arie Are the best.

[@zibusisomasuku]

This is probably the best explanation of torque and horsepower I've ever watched. Kudos 🎉

[@therealtony]

So what I'm getting from this is that the amount of torque at the crankshaft is not an important number. So why is it always talked about like it is? Because of a lack of understanding and of course marketers know this so they perpetuate the misconception.

[@pleasedontwatchthese9593]

You hit the nail on the head. Peak torque is kinda useless figure and is only talked about because of momentum. It doesn't matter if it's a useful number to the maker if it sells bikes

[@currycel470]

​@pleasedontwatchthese9593 yeah, there are still a lot of dudes in comments thinking torque makes a difference in acceleration. If two bikes have the same hp then they will accelerate the same regardless of torque difference. Only difference will be bike with lower torque will have to rev lot higher.

[@evilwestsidefan9249]

​@@currycel470 the bike has to Rev higher to create similar torque, torque is the turning force of the engine, HP is how fast the engine can work. The higher the torque the faster you take off, how fast you can go is HP. So a Harley will beat a Sport Bike off the line but the Sport Bike will then pass the Harley. Harley high Torque low RPM, Sport Bike high HP high RPM.

[@martinplayer23]

@@currycel470bro it does😂, not a big difference, but it makes a difference

[@Coolgamer400]

​​@@evilwestsidefan9249no. Since the kawa will rev 3x higher you can gear it 3x lower and then it will have more torque and more acceleration than the harley. Why? Because only horsepower matters for that, torque is manipulated by gearing.

[@magellanicspaceclouds]

Very easy and straightforward explanation!

[@pleasedontwatchthese9593]

In video game terms tourqe is base damage, rpm is how often you attack and horsepower is dps.

[@Stuey105]

That’s actually a pretty good analogy.

[@Al.j.Vasquez]

This is by far the best explanation and showcase I've ever seen.

[@niclawrenceRS]

Definitely using this in my Motorcycle and Auto classes. Surprising how few and far between good videos about horsepower and torque are, specially in education. Thanks Ari

[@pulaktrivedi9743]

I've seen 10+ videos on torque and hp and this has literally the best explanation.

[@120hz]

More hps means the ability to overcome physics at high speed & accelerate to a higher speed. High torque can be available in a 125cc however you'll struggle to reach top end

[@636theofthebeast8]

To use a swimming analogy : torque is how much water you push with each stroke (your distance per traction). Power would determine your speed, which depends on *both* your distance per traction as well as your stroke rate (how many strokes per minute). Also, you can have high acceleration even with high hp / low torque, you just need short enough gear ratios. The reverse is not true. Power is the metric that determines how quickly a vehicle could theoretically generate (kinetic) egergy, wich is related to velocity.

[@matt9675]

The impressiveness of Harley Davidsons comes from their extreme efficiency to produce the greatest amount of noise from the least amount of power. Engineering excellence.

[@nerdsofthefist]

I’m still confused on a few things. 1) where do I get that extending wrench? And 2) what’s your bench regime? Oh and what’s torque and horsepower?

[@nickkimmons]

What I think is neat, is that on about 96 percent of dyno runs, if you look at the graph of the results, the HP and torque usually crossover at 5252 rpm (more-so on car engine dyno sheets)

[@waynerobertson511]

P = Torque x RPM / 5250 when RPM = 5250 .. you have P = Torque x 5250/5250 i.e. P = Torque (in magnitude anyway). It's a different RPM if you are measuring in metric

[@xorbe2]

100%, it's mathematic. If it doesn't cross there on the graph, then the hp/tq are in different units or scales.

[@sepg5084]

It is not 96%, it is 100% as long as the engine revs up to 5252. This is a result of the units chosen (HP and lb.ft.). International units will map differently.

[@evandizon4774]

Best explanation i've heard about the differene between torque and horsepower.

[@stoneslash]

Good job. One of the better explanations of the difference I’ve ever heard. With folks like you doing this we will be able to teach kids entirely off of revzilla youtube videos soon.

[@OldmanNix]

Nice. Been checking a few explanations and this one is pretty damn good. Thank you.

[@biocta]

Horsepower is the only number that really matters at the end of the day, torque is obviously important but its job is to generate power. The thing that really made this click for me was realizing that a 500hp BMW 3 series can pull a loaded semi trailer just like a semi truck that makes 500hp. The difference is that the BMW makes 500 hp at 6000rpm, whereas the semi which has 2000 lb-ft of torque makes 500hp at like 1000rpm, so it pulls the weight effortlessly whereas the BMW would be fighting for its life the whole time.

[@HifeMan]

Semi would make peak torque down low 1200-2000rpm but peak power would still be higher in the rev range 3000-5000rpm. Torque gets the semi moving and hp gets it up to speed.

[@biocta]

@@HifeMan Semi trucks do not rev to 3k let alone 5k

[@HifeMan]

@@biocta Yeah 5K would be more of a fully build semi engine that makes like 3000HP lol but you can fine 12 liters diesels that are governed to 2900-3000 rpm’s. So yes they do ;)

[@biocta]

@@HifeMan Yeah those are cool but I’m not really sure what your point is

[@MattMaxwell]

Sort of. With an infinite number of perfectly efficient gears then it only power would matter. In reality the thing that normally matters is the amount of power in the rev range you're using. If you had an engine which produced 10hp from 1k rpm through to 9k rpm but then had a sudden spike up to 170hp from 9k - 10k rpm then it wouldn't be much good to ride and would be very slow except for a very specific use case.

[@addeats]

I've seen several vids on youtube which trying to explain the difference between torque and horsepower... this one is by far THE BEST explanation ever! Thanks Ari!

[@hsxvr_5057]

Ari is the best making everything's clear! I hope zack and Ari will have another Common Tread XP!

[@dragnar4743]

It was one of the best video on yt which explains everything so simply. I knew the formula, but always had a doubt between these 2 terms. And now I get it, why people say cruiser are torque master. And also that gear explanation with animation was also good, initial gears are big, large radius, hence generating more torque / power to move your vehicle. But, at higher speed your vehicle is already moving, u don't need torque, u need fast rotation, hence gears became shorter for high rpm.

[@victorvannatter312]

In a sense this is correct. But in reality, torque doesn’t really do anything. Power is what moves you. It work being done. Your engine can make 200 ftlbs of torque, but if it’s not moving, no work. No acceleration. What we call a torquey engine is simply an engine that makes a lot of power at low rpm. Think of that torque wrench. If it not turning while you’re applying torque to it, no work is being done even though a lot of torque is applied. Otherwise, this was a very good explanation and easy for most people to understand

[@chriskop460]

So basically you are saying that torque doesn't bring you far when the engine is turned off? Or what else do you mean by "if it's not moving"? If that is what you mean, no shit, cpt. obvious, I think everyone got that

[@mithrandirthegrey7644]

Exemplary. Clear. Concise. Perfect. Thank you so much.

[@4CEYLON]

Thanks Ari for simplifying things.

[@The_Inquisitive_Indian]

This is the best explanation available on KZbin right now!

[@scotshanley]

This was hands down one of the simplest and best explanations of torque and horsepower I've ever heard great job 👏

[@ferociouzmonk]

Horsepower is how fast you hit the wall, torque is how far you take that wall with you

[@MississippiMuD94]

😂

[@oto-aoki]

Very nicely explained. Passing it to my son. Thanks

[@chrissunde1104]

As a high school physics teacher I say that you've done an excellent job here.

[@tomma04]

Tried understanding the concept for a while. This video finally helped me understand it. Great video!

[@jpenaflower6595]

I've always been a little confused about the difference so thanks for the video. Great explanation

[@kevinpakravan2947]

Small correction: top speed is usually limited by wind resistance more than rolling resistance.

[@austink641]

It makes me twitch when I hear people say “I like torquey bikes.” No, you don’t. You like bikes with high power at low RPMs.

[@izzojoseph2]

I went through all three levels of calculus, several engineering courses, and a few physics ~ this was the most understandable I’ve heard someone explain this concept

[@saddle8bag]

You miss the same thing as everyone else. In a rotational system, Power, per your equation, is comprised of two components, torque and rpm. At ANY given rpm, if two engines are being compared, the one making more power at that rpm will make more tq at that rpm. It's math. Compare a couple dyno sheets and run the numbers yourself if you don't believe me. The power curve tells a rider everything there is to know about the engine's power delivery. Tq is just telling the same story with a different graph. It's meaningless enough, but the fact that the tq/speed at the rear wheel is what pulls the bike forward makes it even more inconsequential. The power from the engine is delivered to the rear wheel in it's two components, tq and rear wheel speed, via your choice of gear. More tq/less speed in 1st gear. Less tq/more speed in 6th gear. So can you reviewers please STHU about tq. It's nothing you feel. You feel acceleration. The end.

[@pleasedontwatchthese9593]

Yeah you get it. Like the only one here lol

[@saddle8bag]

There's also no such word as "comfortability" and all bike are "approachable" unless they are guarded by a force field.

[@Blockbuster2033]

It's indeed funny how you are the only one in this comments section that truely understood the subject. And the guy with the red profile pic haha. However, it is true, that you basically feel torque, since torque is directly proportional to the force at the rear wheel and therefore acceleration. So yes, you feel acceleration, but by that you basically feel the torque. You don't feel power. That leads to many people shortshifting, because they feel the torque drop off at the top of the rev range and they think that the power drops off, so they need to shift up. But they don't realize, that the rear wheel torque, and therefore the acceleration, is even lower in the next higher gear.

[@ut90J]

This is actually the best explanation of the difference I have yet to see. Finally, something that anyone can understand.

[@themrch4oskol206]

Horsepower is how fast you go into a wall and torque is how hard you go into a wall.

[@taecontent1332]

Well said. 💯% accurate.

[@pleasedontwatchthese9593]

Not true, the wall doesn't know how the power was made. It only cares about the end product

[@Desekratedd]

Facts

[@LTVoyager]

Um, no.

[@abracing199]

Please downvote this out of the eyes of people who will believe it. This is the most nonsensical crap repeated on the topic shared by people with no understanding of the topic.

[@bravokiloromeo1]

Watched this topic a hundred times. I still enjoyed your presentation. Nice work!

[@akshaytandon4792]

Thanks man. Cleared a lot of things for me!!

[@clintvosloo7694]

Stroke is on the crank not the conrod, but yes most short stroke motors have shorter conrods .but the explanation is simple to understand.

[@semistealth718]

It's about time someone explained it in plain normal people speak! Nicely done!

[@SWTrailsAndWheels]

One final bit of the explanation is that a high revving low torque engine can still produce massive torque at the rear wheel due to the aforementioned gearing impact and in the end what you feel is torque at the wheel, not at the crankshaft.

[@mateiberatco500]

That is what I "keep screaming" on all videos like this. They don't specify that "torque at the wheel" is important for acceleration, not at the engine. In a gearing calculation, power is same between input and output of a transmission (ignoring internal losses). But the torque and rpm "value" is what changes. Want more output rpm (=wheel speed)? Torque has to come down. It's why diesel engines are not used in (high-)performance cars.

[@NBSV1]

But, as you gear it down for more torque you loose speed. To try and match the torque output of a large engine with a small engine you would end up needing to shift a lot as the gearing would be very short. Everything is a balance. That’s why heavier bikes do better with high torque engines that produce relatively less horsepower. You need that high input torque to get the mass moving. And, generally a heavy bike is going to be more about comfort where you don’t want an engine screaming at high rpm all the time.

[@mateiberatco500]

@ In real life you won't find the same transmission ratios on a big and a small engine. The "design target" is a "target max speed" and spreading it between 5/6 gears based on power band (i.e.: not peak engine torque). I agree that the small engine will scream, but the wheel torque will be comparable (if the power is comparable). Edit: If you care about acceleration, then "as you gear down for more torque you loose speed" is not really logical. You downshift because you already lost speed and want to regain it asap. If you are at peak engine torque rpm, then downshifting will, most of the time, get you more wheel torque because you shift into higher power rpm. And that was my main point of "wheel torque", not "engine peak torque".

[@NBSV1]

@@mateiberatco500 You have to account for input RPM and output RPM as well. At the end of the day it isn't that simple because when you gear down for more torque you loose output RPM which is the speed. Yes, if you're going up a hill you may need to downshift to maintain speed. But, when you downshift the engine RPM has to be higher to maintain that speed. At which point you would eventually need to upshift again because you will run out of engine RPM if you keep accelerating. I will argue that just wheel torque doesn't mean anything. I can gear down a tiny engine and get the same wheel torque as a semi truck. But, the output RPM will be very low. That's why you need to account for RPM and not just the torque numbers. It's also part of why a higher torque engine can pull heavy loads better than a low torque engine. You could gear the low torque engine so the wheel torque is the same, but you need the high engine torque in order to have high enough gearing to get the speed.

[@mateiberatco500]

​@@NBSV1 First of all: I'm fighting against "big torque numbers" (instead of "power") and how that number should not affect buying decisions. That's from where I say "wheel torque" makes more sense. Granted, it's not a beautiful single advertisement-friendly number like engine peak torque, but I also want to see the engine graph when I shop for a vehicle (and if they would provide "wheel torque vs speed for each gear", that would be my auto p**n). "when you gear down for more torque you loose output RPM which is the speed" please stop saying this. The rest of that paragraph I agree. But the output rpm/speed will not drop unless the vehicle is in the air (or hard braking or some catastrophic failiure). Vehicle inertia si orders of magnitude bigger than engine inertia to raise it's rpm. Also "gear down for more torque" - if you mean engine torque (cause everybody assumes that when talking about torque in cars/bikes), not true in any cases. You gear down for more engine power, which leads to more wheel power, and that is proportional to wheel torque at the same speed (again, speed change is negligible during a shift). Now, regarding your 2nd paragraph: "I can gear down a tiny engine and get the same wheel torque as a semi truck. But, the output RPM will be very low." We really need to define what we compare. In the video they compare a 80HP/110Nm Harley with a 110HP/50Nm Kawasaki (not sure if torque is in nm or ft-lbs). If the wheel torque vs speed would be overlapped, I would expect both to accelerate similarly until Harley tops out, because the Kawa has gearing spread to an, at least, extra 50% top speed for it's +50% HP. And that is my point: engine torque is meaningless for comparison. You need to get wheel torque graph and compare them. Otherwise we would see diesel engines is all car races. PS: Acceleration is defined as force / mass (from F=ma), force is torque / wheel radius (from Tq=F*len). So how can you say "wheel torque" does not mean anything?

[@paulocarreiro5855]

I learned physics at a university and I still enjoyed this video! Thanks.

[@blackbarry]

I didn't realize I could understand this topic so clearly. I used to think I kinda got it, but with your explanation, no doubt. Thanks very much 👍

[@Dhruv-_-0.]

I understood within the first 15 seconds of the video. Kept the video playing, and now I've to go back to the first 15 seconds.

[@michaelskinner896]

Good demonstration of these two very fundamental concepts.

[@notsafe8474]

such a great way to explain this. im using that transmission one cause that is the hardest part about teaching someone besides the clutch.

[@upendersinghraghav1498]

Hey man Great seeing you doing well i have watching ur videos for a long time and also long before you had a little accident. I don’t know if you will see this message but still felt happy seeing u do well 😊

[@baddgoat85]

This is the best explanation I've found. Totally clear now. Thanks.

[@cascadesouthernmodeltrains7547]

When learning mechanics one of my instructors explained the relationship like this. Torque is the amount of work you can do, Horsepower is how quickly you can do that work.

[@motominded5275]

not quite right, HP is work you can do...

[@TwonyTheProducer]

Torque is the amount of cargo boxes you can carry in your hands, Horsepower is how many cargo boxes you delivered. When boss asks, the only matter is how much work you did end of the day. Horsepower is a final result of your engine, it shows you how powerful you are, Torque and RPM is your tools to get that final result, it doesn't matter more torque vs more rpm, if you have same amount of HP, the same work done. The acceleration, top speed, carrying weights, going uphill, its all releated to Horsepower, not torque itself. If you do a research about torque curves in semi-truck engines, you can see its actually making more Horsepower at the low end rpm band, not torque itself. You can always make your Inline 4 Racing bike a good heavy load carrier with very short gearing, it will produce more amount of "Wheel torque" than harleys, because you adapted your power to the low speeds.