For best handling, don't change the tires first

So many people change the tires as the first step in improving handling. But I suggest you don't - and here's why. Buy the book now at www.amazon.com/dp/B0D7327WSB or Amazon in your country.

[@terranceaskew3165]

I dont usually go around defending youtubers, but yall really need to listen to what this guy is saying. Like, really just sit back and absorb what is being "taught", instead of trying to argue. Everything said in this video and in others, rings extremely true for daily, spirited, and light track usage. ..stuff that you wouldnt know or learn unless you had a degree, or decades of experience. And he is giving this knowledge for free....some of yall need to stop arguing, listen to what is being said, and say thank you. BTW....thanks for uploading these videos!

[@LeHazy]

Some morons just don't listen

[@banovsky]

Shout-out to Julian for not only educating people but for also responding to comments from people who are using their lack of knowledge to explain why his lessons don’t apply to them :D

[@Remenschneider]

I tried switching to very grippy tires as first mod, would not recommend it. With stock suspension, you will be hitting the bump stops way too often, have excessive roll and pitch, and experience large dynamic toe changes. If your car is older, replace your suspension bushings first.

[@THESLlCK]

thank you for this

[@tiitsaul9036]

Better tires made my 1985 BMW handle worse. The suspension was designed for not so good TRX tires and with improved grip loaded suspension more than optimal. Increased suspension travel caused camber gain in rear and camber loss at front, resulting in nervous handling. I "fixed" it with stiffer suspension. Now the whole car is flexing and squeaking.

[@michaelblacktree]

Now it needs chassis reinforcements. 😎

[@ArchOfficial]

I don't think the camber was to blame for nervous handling. Usually the front will be around +3 to +4, so your rear might be just about around 0, which will understeer a lot, but it should be pretty stable. Bumpsteer would do you in more; lots of toe-out gain in the front and toe-in gain in the rear on those cars. However you did probably get, if you're on OEM springs, a good 30mm (!) or so more vertical deflection if my math is right, which means you'd be sunken right into the front bumpstop and probably approaching or sunken into the rear, depending what model your car is. What tires did you put on?

[@tiitsaul9036]

@@ArchOfficial it's E28. It definitely gains some negative camber in the rear during full compression. I haven't investigated toe changes during the suspension travel, but I'm sure it's not ideal. Currently running Bridgestone re003 205/55/16. Plenty of grip for this old shitbox.

[@user-om9gy3mg7x]

Sounds like your car should be more stable Camber gain in the rear should give the rear more grip, the front would lose grip due to the camber loss. That would make the car understeer in the corner.

[@helixworld]

It sounds like you learned a lot about the car after fitting better tyres.

[@Gibbonium]

I agree. Very well put to words. On the topic of sway bars, shame there isn't a company selling smaller front sway bars. It's always only bigger or nothing. They're great for changing the handling balance, but you can only buy bigger ones. Your videos are very insightful, they've helped me understand a lot of new concepts. Thank you for making them!

[@JulianEdgar]

You can get sway bars made in whatever diameter you like. See my recent video on sway bars.

[@neversettle7666]

Or remove them all together. Little known fact, some of the fastest modified FWD and AWD cars in the world don't run a front sway ar

[@johnkim3858]

The single sway bar change will tune the normal load distribution during cornering; it is elegant and probably the least invasive for a significant effect. However, this video assumes that the front and rear tires must be identical.

[@JulianEdgar]

Well, on 99 per cent of cars f and r tyres are identical.

[@johnkim3858]

@@JulianEdgar I did not know most passenger cars ran a square setup. Thanks for letting me know.

[@benwhittaker8630]

I don't think it matters if the tyre setup is square. At the end of the day, if it understeers or oversteers with any given setup, you could make a handling change to suit.

[@zzwk24]

And by the same, it doesn't imply "square," it's compound as well. I run a staggered setup 16x8 front and 17x9 rear. 🤷🏻‍♂️

[@Anon.G]

@@benwhittaker8630yes but increasing front tire size in an under steering car would improve load sensitivity and increase front grip. That’s one way which changing tires would change the handling

[@HardstylePete]

I think people prefer to change tyres so that the balance of grip remains constant but the overall mid corner speeds are higher. A lot of cars are setup from factory with somewhat predictable and safe understeer, whilst not optimal, its an easier driving experience for the road. All that being said, I had a 2011 Ford Focus LV and I raised the steering rack to reduce the large amount of front suspension toe out under compression. That really improved the handling.

[@trevor6814]

It’s important to note that even same size tires change handling dynamics via sidewall stiffness as evidenced by blind tire tests performed by Tyre Reviews here on KZbin. While it can be argued the F/R balance remains the same between tires, there is a difference in “subjective” feel. I do however share the sentiment that lowering treadware is often a bandaid for poor optimization of mechanical grip.

[@Weezal]

Love your channel! Great explanations and I love your enthusiasm

[@jce102jz4]

Absolutely excellent content thank you.

[@johnmcdonnell81]

Nice bit of clarification Julian. Top stuff as usual.

[@chrstphrr]

Given the few videos you're teasing us with, this new book seems quite a promising read! Looking forward to when you can give a firm announcement for when it's ready to be bought up!

[@nicktwentyfive]

You have made me question my front sway bar I put on my e36 non-m bmw 😂. Your videos are thought provoking and I appreciate that kind of content

[@SideshowBen206]

Looking forward to the book release

[@jazzistation4802]

I have to say these videos are very educative and i appreciate the passionate way you explain things, i'm subscribed since the last year or so but i really like this channel and hope to see it grow faster!

[@JulianEdgar]

Glad you like them!

[@davidpando7970]

You are so cool thank you sir.

[@ellisjackson336]

I love your philosophical approach. Right now, I have some cheap no name tires fitted to my car. I’ve been wanting to get gripper tires. But I have also asked myself “am I ready for gripper tires? Have I done everything I can to maximize what I have right now? Has my skill even outgrown this setup?” All I have are some coil overs with slightly stiffer than stock springs and the shocks set to full soft. It’s not a flashy setup and I can’t even say it’s particularly fast. There can be long oscillations over bumps. But the car feels nice, safe, and predictable in terms of the handling right now. Maybe a bit too low lol

[@moneyshifters]

I think this is a different case and I'd definitely get some at least enthusiast grade tires. Curious to see what Mr Edgar says though.

[@dielaughing73]

​@@moneyshifters yeah I don't think he's advocating sticking with cheap, or old, or worn-out tyres. Get decent tyres and use them to their fullest before going to extreme, sticky low-treadwear tyres

[@wasdwasdwwasd]

This reminds me of the 6th gen Camaro Z/28 which wore super sticky P Zero Trofeo Rs in addition to the lovely 7 litre LS7. GM put the same tyres on the more powerful supercharged ZL1 out of curiosity but it was slower around their test track because it hadn't been designed with the tyres in mind.

[@silvenshadow]

So this is a very controversial topic. Having 'perfect' balance isn't always desirable. But I agree that, fixing bad behavior with great tires is just looking to have a problem at a higher speed.

[@parrotraiser6541]

A first step in checking the balance is modest changes to the tyre pressures and their front to rear distribution. E.g. if you have understeer, add some air to the front.

[@JulianEdgar]

Yes, sometimes. (On some road car tyres, increasing pressure does not increase grip. I am in fact waiting on approval to use those test results in the upcoming book.)

[@blanchimont5587]

i think tires can indeed affect handling, just not with grip as you have mentioned here. i think the sidewall stiffness has a large impact on the response and movement on the car, but in isolation without dialing in the suspension is probably not utilized well

[@eatshityoutube1]

In sim racing, i found that an LSD makes to most difference in handling. Followed by a roll bar to make the car neutral. Then camber so the tyres compensate the roll at the curves. I don't see the point in putting slicks if your car suspension is all over the place doing one wheel burnouts at every corner exit. Great vid!!!

[@johngamer6255]

Hey man I really appreciate the videos you're putting out because they're really simple to understand. I was wondering what level of education or what I'd need to know to understand and comprehend your books before I consider purchasing them.

[@JulianEdgar]

My books are all written for normal car enthusiasts. Have a look at reader reviews on Amazon.

[@moneyshifters]

If upgraded tyres cause certain behaviours to occur at a higher speed 5:26 (and a couple other points), then surely that is a desirable outcome? It gives a higher limit for highspeed cornering where the car stays predictable. Great video. Keen for the book.

[@JulianEdgar]

[Shrug] It understeers at 80 km/h cornering speed, but with grippier tyres it now understeers at 90 km/h. But I'd prefer it didn't understeer....

[@moneyshifters]

@@JulianEdgar Ahhhh, FIRST in the title is the key word I missed it seems. Thank you for clarifying.

[@johnmann7o2]

This man speaks the truth, setup the cars suspension geometry first, then get the proper tires. No fun if the car handles like a boat with 200 tread tires.

[@onlyifusayplz5407]

I will say that grippier tires might actually help highlight other flaws in a car's handling than just under- or oversteer. In a way that actually makes it handle worse from a street driving perspective, despite pulling more lateral G.

[@aggressiver_kr4187]

i have fitted worse tires in the back and i think it has the same effect but i never tried a stiffer roll bar, so is the effect really the same? +if my tires are cold and im really pushing the limits i often have a 4 wheel slide when i let go of the gas ( i cant really control my car with the gas bc 75hp) should i really fit a stiffer rear bar? (when the tires are warm its more understeery)

[@Axman6]

Will the book cover anything on 4wd suspension? I’m assuming it’s mostly focused on on-road performance. Really enjoying the channel, it’s given me a lot to think about as I begin to look at working on my LandCruiser.

[@JulianEdgar]

The book only briefly covers some four-wheel drive applications (eg the Toyota Kinetic Dynamic System) however probably half the book is applicable to *any* vehicle with suspension.

[@atlasdelmar]

Then, do you believe that your book will cover Audi Systems' "adaptive AWD system" (QUATTRO) adequately? I agree with your video message that by simply making the cars turn in more neutral, their driving characteristics will become more manageable. My concern was aimed towards cars with HALDEX type AWD systems that split torque between front and rear, whilst also further distributing power from the inside to the outside wheels. Making a car behave neutrally with such AWD systems is a topic of interest.

[@JulianEdgar]

All-wheel drive is covered, yes. In fact, has a full chapter.

[@JulianEdgar]

In the chapter on AWD obviously I cannot cover all car AWD systems. However, the premise of the chapter is that to make correct decisions regarding handling modifications, on an AWD car you first need to understand how that car's AWD system works in distributing torque, both f/r and also (in some cars) side to side. I summary form I cover constant all-wheel drive, cars that start FWD and change to AWD in some conditions, and cars that start RWD and change to AWD in some conditions. I have owned quite a few AWD cars and so it is a particular topic of interest to me.

[@michaelblacktree]

I've always been a big fan of neutral handling, because it lets you use all the available grip.

[@JulianEdgar]

Yes indeed, but it seems from a lot of comments here that that self-evident truth is not the way to go!

[@yowie0889]

Not disagreeing, but on that point - I've heard commentary/interviews about some race drivers wanting to deliberately induce (eg) understeer through a sweeping corner so they know which set of actions they'll be using to balance the car. As opposed to "could go either way".

[@JulianEdgar]

Neutral refers to the car in steady state cornering, as described in the video. Throttle changes (among other things) will change handling attitude.

[@michaelblacktree]

@@yowie0889 - You're talking about the personal preferences of some race car drivers*, which isn't very relevant to a normal person driving a street car. _*Some, not all. Because different drivers have different preferences._

[@benwhittaker8630]

On the car you mentioned you had that suffered from oversteer, you said it was rectified with a torque split adjustment, I'm curious, was the a Subaru or similar with an active centre diff, or did you carry out some physical modification to achieve this? If so, what was done?

[@JulianEdgar]

R32 Skyline GT-R. Made my own electronic torque split controller.

[@skippy2987]

Turns out on the R32 GTR it reduced front drive at high G forces (via a computer controlled clutch pack), probably to give the car a more traditional rwd feel. If you tell that particular car that it *isn't* going around a corner it will send more power to the front under acceleration. It's a little more nuanced than that, but that's the basics.

[@turbolag94]

From a conceptual point of view I agree and I understand this is talking about the sequence of modifications rather than one or the other, however, Personally I start with tyres first, and then modify the rest of the car around the tyre I aim to use instead. If I were to start with modifying suspension/where the power actually goes (ie. torque split/diffs etc) and not touch the tyres first, then wouldn't the new tyres (lets assume the new tyres allow the car to have more grip in each direction) mean I now have to retune all of this? From a practical point of view, if I know the limits of my driving ability, and I am able to keep the car on its limit whilst handling, why would I not start with these, assuming I am modifying the rest of the car to suit anyway? Ultimately I would choose tyres over any other modification if I had to choose one or the other, not to mention also potentially improving straight line grip whether it's acceleration or braking too. Stickier tyres have significantly changed how the car has felt (particularly in terms of body roll). Lower grip tyres have made standard suspension setups feel fine from experience, but throwing better tyres on exposes the weaknesses of them. This is all assuming I am doing both - attempting to improve the handling and increase overall grip. I think it's better framed by addressing the end goal of a better handling car, not so much an overall faster one. My point is that depending on how the car is set up, it must be optimised for that specific combination of parts. I wouldn't optimise the car's handling first, then do tyres and expect everything to just be better. Personally I tune my suspension around the tyre as I find it is best utilised this way. Great video and good discussion on this topic!

[@JulianEdgar]

Yes, but there are two issues with what you describe. (1) As I mentioned in the video, I have found I often have no need to change the tyres if the car is set up to better utilise the total grip *that is already present* - and that's a major saving over hi-po tyres. (2) It is much harder to set up a car when the grip levels are very high - for me, at least, it's less obvious what is happening. In 40 years of driving and car modification, I have *never* had a car's handling feel fine on low grip tyres and bad on high grip tyres. (And that includes going to semi-slick street legal race tyres.) Body roll on modern cars is so low that stickier tyres, even if the tyres increase lateral acceleration values by, say, 10 per cent, has very little negative impact on handling. Small amounts of body roll matters little in handling - it just gives a bit of camber loss.

[@AbcdEfgh-sq2tf]

I think a more accurate title should be: The difference between handling/vehicle dynamics vs grip

[@JulianEdgar]

I see it more about the suggested sequence of modifications.

[@TheLastS209]

Is it not true that optimal suspension setup is also tire dependent? In that case, it wluld be better to change tires first, and then optimize suspension for that tire. Id like to hear your thoughts. Thanks

[@JulianEdgar]

For road car handling, tyres make far less difference than fundamental suspension set-up.

[@tturi2]

for me, i just have terrible coilovers in my car (yes i wish i went for a properly engineered dampener kit like non adjustable bilstiens)

[@ericzmusic]

I have a stock Civic EG Hatchback and grippy tyres have made this the fastest cornering car I've ever owned.

[@JulianEdgar]

No doubt. But what if you developed the suspension first?

[@ericzmusic]

@@JulianEdgar It would be a lot better. I don't want to find the grip limit with my current tyres because it would be a scary amount of Gs. This video makes me wish I had cheap tyres to throw on and test with.

[@JulianEdgar]

Sometimes it's worth having two sets of wheels/tyres.

[@darius2640]

Im surprised you didn't mention changing only 2 tires, upgrade those who let go of grip first. Or changing tire pressure.

[@JulianEdgar]

Sure, but (1) very few people change only a pair of tyres to something with far more grip, and (2) changing tyre pressures doesn't always work - it depends on the tyre.

[@Pickfordr100]

Fair point but what do i do if no sway bars are available for my car? Has none from factory either

[@JulianEdgar]

Get them made. Any spring manufacturing company can make them - they're just bent bits of spring steel.

[@williamsaundersswan8370]

I’m a little worried about changing sway bars in my fwd car that understeers. Because a lot of the weight is in the front, the rear can be too un-loaded causing oversteer sometimes. Is there a way I can decrease under steer without worrying about sketchy oversteer at steep declines and heavy breaking?

[@JulianEdgar]

If you are worried about oversteer, you need to do things that increase only front grip, rather than change car balance. Stickier front tyres, negative front camber. (Also, using less power in corner exits and changing the way you brake.)

[@williamsaundersswan8370]

@@JulianEdgar Thank you very much for your reply.

[@elscorchomotorsports7199]

You should be clear what the context of your statement is. Is it just for a road car, to make it more satisfying to drive? Or a car that is used in competition, where faster around a circuit is the goal? If the latter, i would like to challenge you to a race with identical cars. Yours with a single sway bar change and mine with better tires. There is a reason most people recommend better tires first.

[@JulianEdgar]

I write for people primarily modifying road cars, as a glance at any of my videos will show. (Actually, when I think about it, your suggested race would be between a car that had its handling first optimised and *then* had the tyre upgrade. That’s what the video suggests.)

[@Vattiis_Happonnen]

@elscorchomotorsports7199 couldn't agree more. The individual car, mission and conditions will ultimately determine critical performance metrics. In more cases than not though, tires are the single most limiting factor in performance ceiling

[@JulianEdgar]

How can tires be the single most limiting factor when in nearly all unmodified cars, the grip of the four *existing* tyres has not been fully utilised?

[@ergoproxy-gx2cq]

​@@JulianEdgaryeah i though the obvious context was road cars

[@BrodeyDoverosx]

@@JulianEdgarsimple. Increasing the grip of all four tires allows the DRIVER to still do all the wrong things, but they will do the wrong things at a faster speed. You will see someone in autocross, run 60s after a day. Throw tires on the car and they will knock off 4 seconds. Not to mention that tires ALSO change the handling balance of the car. You can induce handling balance with tire pressure, but the best modification to make is ALWAYS driver mod. I’ve been autocrossing for over 12 years and I’ve started a consultation company modifying road cars for autocross/track work. DoverLabs. My tuned cars have placed in the top 3 finishers, beating out the cars tuned by folk lore and the usual “you must do things this way”. I advise on springs/shock valving/sway bars/bump stops etc. I’d like to think I’m an expert, because of my track record but also because the fast people pay me to make their cars faster. I definitely understand what you’re saying, it’s just that I’ve never seen a single person pick up time on track from a sway bar, for example, but I’ve seen it 100% of the time from tires. As well, if the driver gets a driver mod they’ll pick up big time…just don’t expect it to come easy. I’ve been at the tail of dragon event, where someone said “these cars are impossible to oversteer”…. And I gave an odd look, because I had been racing for 5 years at that point and my Abarth in stock form was easy to rotate if you could drive around the car’s limitations. First corner out and my rear end stepped out. Driver Mod/weight balance control is always the limiting factor.

[@s.lacasse8337]

I have strange question. If sway bar act as a torsional spring, why the link kit is not made with a damper? More spring, so more damping?

[@JulianEdgar]

Because a damper (even a torsional damper) provides no resistance except when *change* is occurring. A torsional damper used in place of a sway bar would provide resistance only when turning into/out of the corner. That's exactly what happens now in roll with conventional suspension dampers - they are effective only in roll transients.

[@s.lacasse8337]

@@JulianEdgar Thank you very much for the explanation. This is clear now.

[@aljowen]

I would have thought getting an alignment would be more important than sway bars for handling? Since poor handling can often result from the alignment being out. But for me I would argue tyres are perhaps more important than sway bars for most people (with post 2000's cars) . Since they offer an improved safety factor in braking and often especially in the wet. They also tend to behave more predictably than budget tyres, and have less snappy transitions between having grip and not having grip. In my own experience of designing suspension systems for simulated vehicles (to be clear I'm not an expert on the subject, but many thousands of people have driven the simulated cars I built and provided feedback) people tend to value predictability highly, since spiky or variable behaviour generally makes reaching limits a hedge finding exercise xD Most people aren't reaching the point of understeer or oversteer in road driving for pleasure. And personally I am of the opinion that the public road isn't really the place for pushing a car that hard. So while they may not improve "handling" by your definitions, I do feel that in practice grip is an important aspect of how a car handles on the road. But I do see where you are coming from.

[@JulianEdgar]

1. Alignment is quite trivial compared to the handling change that can result from altering sway bars. 2. Yes, tyres do make a major difference to wet braking. 3. People often reach the point of oversteer or understeer in emergencies. 4. Differentiating total available grip and handling allows a much more logical development of suspension modifications.

[@Anon.G]

Wouldn’t reducing or increasing tire pressure be an easier way to change distribution of grip?

[@JulianEdgar]

Why not make the most of the grip that is already available, and use all four tyres to best effect?

[@thedude4795]

ive got 23.6 mm stock front ARB on my golf, and 20.0 mm stock Rear. If I push the car somewhat hard in a corner, the front loses grip first. Which end should I change? There are many options of 24 and even 26 mm rear ARBs.

[@JulianEdgar]

Have a look at my recent video on sway bars.

[@thedude4795]

@@JulianEdgar I actually did, before seeing this one. Sorry, but Im still not sure what which end to to begin with...

[@Drunken_Hamster]

@@thedude4795 Stiffen the rear OR soften the front to increase oversteer/decrease understeer. If possible try fitting a stock rear swaybar to the front and leaving the rear swaybar at 20mm. The cheapest and easiest thing to try first would be simply disconnecting your front swaybar and trying the same test again. Also, be careful of liftoff oversteer. FWD cars tend to have it more than anything other than a mid or rear-engine RWD.

[@jameshaulenbeek5931]

I only changed my tires from the stock/OEM set as I needed tires, and didn't want to run summer tires in the winter. The car came with Continental ExtremeContact Sport tires that I swapped for a set of DWS06+. I have noticed a slight change (decrease) in overall grip, but I have yet to push the car to it's full potential of handling. I do think changing tires for environmental reasons is extremely important, and changing a "cheap" OEM tire for a better quality tire is fairly important, as well - many OEM tires on new cars are becoming poorer quality to save cost, unless you're purchasing a brand's "halo" car. I do fully agree that changing a tire just to try to remedy a particular handling characteristic, like cornering, is quite silly. Weight distribution and suspension setup are far more important, and then you switch to a different tire and fine tune the setup for the tire.

[@brunm9203]

So by your logic here, where do the tires fall in the order of modification? Sounds like maybe as the last thing, since you could upgrade bushings, spring rates, dampers, etc. and still be "optimizing" the handling? To me, it would make more sense to change the tires first, then you are optimizing the whole package based on the increased amount of grip you will get out of the improved tires.

[@JulianEdgar]

But as I said in the video, you may find there's no need to change the tyres if you're making the most of the grip that is already available but is not being used. That's my direct experience. Most cars these days have huge total grip - it's just all not being used.

[@keisuketakahashi3597]

Sir Can you please explain the Why some scooters and motorcycles rear suspension is place at certain angle? Because I have seen some electric scooter which have near horizontal suspension and and some scooters vertical suspension. Thanks.

[@JulianEdgar]

Dampers? Springs? Both?

[@johnkim3858]

It is probably due to getting the desired motion ratio between the travel of the spring/damper and the travel at the wheel. Modulating motion ratio could be getting a progressive spring rate out of a linear spring through the linkages or achieving higher damper travel per wheel travel to make the damping sensitive to small bumps.

[@keisuketakahashi3597]

@@JulianEdgar yes both combined for rear suspension

[@JulianEdgar]

It's usually to change how much the spring/damper moves compared with the vertical wheel movement. (This is called the motion ratio.) Make a little model and try adjusting the angle of the spring/damper while moving the wheel up and down. Then you'll see how it works. You'll also see, if you make an accurate enough model, how for angled spring/dampers, the motion ratio changes during wheel movement.

[@keisuketakahashi3597]

@@JulianEdgar Thank you sir I wondered that for a while now I know.

[@AlienLivesMatter]

I like to get both outside tires exceeding their capability

[@JulianEdgar]

Why not all four tyres?

[@WyFoster]

Im my experience, tires have a large impact on vehicle balance. I find softer, grippier tires increase oversteer and harder tires do the inverse.

[@JulianEdgar]

Can you explain the mechanism by which that can occur? (I don't think that happens.)

[@WyFoster]

@@JulianEdgar I can offer about 25 years of anecdotal evidence as a racing driver. Also, I was an intern in my days in college for an Indycar team. We would always add front downforce to the car in a race when swapping from the softer option tire to the harder primary tire when doing a pitstop or vice versa. (Front wing was quick adjustable)

[@JulianEdgar]

Thank you but I am after evidence, not anecdote. Can you explain the mechanism by which what you suggests occurs?

[@WyFoster]

@JulianEdgar I would think that the suspension is put under further load. More dynamic roll center movement, more heave, more weight transfer forward under braking allowing for a more sensitive turn in. If the suspension wheel rates are varied front to rear the stiffness relative to each other will spread in percentage with the extra loading. Say a 9kg/mm front vs a 6kg/mm rear. I believe this characteristic of tires affect on handling balance to be a well known fact. Supported by evidence of teams in a multitude of series where several compounds are available making requisite changes to the chassis when tire compound is changed. Be it either aero or mechanical balance, or both.

[@JulianEdgar]

OK, but if you watched the video you will see I was very careful to describe only steady state handling, not transients. And on a normal car, changing tyres makes only a minor difference to lateral acceleration figures - so very little difference to roll centre migration through changed body roll (that I also mentioned in the video).

[@Hapkido82AUS]

Driver mod is the best mod first..

[@Saad-yk8qp]

So i took your advice and to find a rear sway bar. my car got a double wishbone in the front and a rear solid axle, it has a 21mm front sway bar and didnt come with a rear one. I managed to find a 17mm rear sway bar from the junkyard and got it fitted, it was very easy and straight forward. I noticed a difference right away, in low speeds its the same but in medium speeds to high speeds it feels tight and suddenly i got more steering feedback lets say?. But i want more, greedy humans eh?, But will that decrease rear grip in favor for frontal grip? If i can find a 21mm rear sway bar that will equal the front one. I dont wanna have an oversteery car especially im no race car driver. I have medium stiffness springs with stiff heavy duty shocks that are awesome, so what i was thinking is, get some soft rear springs and add that thicker sway bar and with that soft spring it should give me some additional grip? To some degree of course but what are your thoughts.

[@JulianEdgar]

To go from no rear sway bar to a 17mm one is a big jump, and with a 21mm front bar I'd stop there (assuming roughly equal weight distribution, and similar sway bar motion ratios). Softening the rear springs will degrade the effect of the rear bar. Don't forget that the back will now be more slippery in wet conditions - so get to know the car's new handling step by step.

[@Saad-yk8qp]

@@JulianEdgar for the weight distribution, its mostly all in the front half of the car, the rear is very light compared to the front.

[@JulianEdgar]

No, you need actual measurements - what percentage weight on the front versus the back, loaded with the driver at least?

[@Saad-yk8qp]

@@JulianEdgar i have found some data in old service manuals, it appears to be 58/42 The total weight is 1805kg without a driver

[@JulianEdgar]

I'd probably stop at that point (especially if you understandably don't like the idea of high speed oversteer) and move to other grip aspects like tyres.

[@cuoresportivo155]

On bad suspension, you can definitely have too much tyre (thus grip). The result is a more dangerous car.

[@ChainsawChuck13]

I have a tire theory and I want you to tell me if I'm close to getting it right or not: If you're just "doing stupid stuff on the street", anything under 400 treadwear (as long as it's not a raised-white-letter nostalgia tire) is *philosophically* interchangeable.

[@JulianEdgar]

Tires vary in a lot more than just rubber softness (as indicated by the treadwear indicator).

[@ChainsawChuck13]

@@JulianEdgar That's why I specified "no nostalgia tires". There will be exceptions, but I mean "within the realm of modern-concept summer/performance tires". (I should have also specified that this wouldn't really apply to Chinese-label tires, which have a predictably poor reputation, but still)

[@JulianEdgar]

I don't find a lot of difference between mid-price tyres from Bridgestone, Michelin, Pirelli, Kumho (etc), if that's what you mean.

[@ChainsawChuck13]

@@JulianEdgar That's part of what I meant. An example: in one test of tuned cars in Japan, one of the entries was a daily driven RX7 that rolled in on a used "extreme summer" tire from, if I remember correctly, Bridgestone. It was already in the running for top spot, despite all the other cars running on semislicks, but tuner and driver both believed there was more time in it. So they switched to a brand new set of semislicks from the same manufacturer, and gained... 0.2 seconds, over a very technical 25 second section, with a veteran professional racer in the driver's seat. A minor tweak's worth of time, at best - and again, that's with a summer tire that already had some wear on it. Meaning, if you're just out having fun, you'll probably never notice the difference, except when it rains and you suddenly have no grip, or an emergency pops up and you suddenly have no money

[@CurboroughSprinter]

All makes logical sense to me. This is why tirereviews channel can be confusing when he does a tyre test and on some the car understeer but on others it oversteers. That makes absolutely no sense!

oh, it really make no sense to you? Both are thruth. JE just focus on car handling and grip on the same tyres. TR focus on differences between tyre brands/types and their behaviour on a specific car (with its own fix handling). AND what is also important to mention, TR tests the tyres in a dynamic use where weight distribution changes rapidly and thus loading those tyres on a fixed stock suspension makes big difference. Some tyres just work different than the others when loaded vs unloaded as weight transfers. On the opposite, JE talks about maximum cornering ability (increasing cornering G`s and balancing under/oversteer). This is great in long big radius turns without heavy braking or accelerating (or mid corner for maintaing higher minimum corner speed).

[@SgtAutmn]

Too late. R888 installed