Handling - low or high profile tyres??

Handling - low or high profile tyres??

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300bhp/ton

Original Poster:

41,030 posts

191 months

Wednesday 9th September 2015
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Handling is always one of those things that causes much debate. I was reading an interesting thread over on the MROC about tyre sizes and have read other places such as on Mini forums that smaller wheels give better handling.

Not sure that is what is meant always. Anyhow the MROC went on to say that more specifically high profile tyres handle better than low profile ones. Yet no reason could be given why some cars handle very well on low profile tyres.

On the flip side I've read/watched stuff in the Subaru world that said and claimed low profile tyres made the cars handle better.


Points of interest may include things as the tyres slip angle, the rest of the suspension setup (MacPherson struts vs double wishbones etc etc). Debate over road holding and handling once grip is lost. Fastest way round a track.


But what's your view on it?

Do you think high profile tyres handle better or worse than low profile tyres? Is this a general rule or vehicle specific? Does it change for track vs road use?


If you took a car with with 15" rims stock and replaced them with 18" rims, but kept the tyre diameter and width the same, would it ruin the handling?

Or if you took a car with say 19" rims on as stock and replaced them with 14" rims, but kept the tyre the same diameter and width, what would it do to the handling?







skene

2,298 posts

173 months

Wednesday 9th September 2015
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Always been my understanding that low-profiles lead to better handling due to less sidewall flex.

Monty Python

4,812 posts

198 months

Wednesday 9th September 2015
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I'd guess that it would depend a lot on how the suspension coped with the changes - the McLaren F1 has pretty high profile tyres and seems to cope pretty well (unless your name is Rowan Atkinson and/or it's wet), and F1 cars manage.

I suspect most super/hyper cars are set up to use a specific wheel/tyre size and wouldn't react well to changes, whereas ROTM cars are set up to cope with a broader range.

Limeymk1

43 posts

178 months

Wednesday 9th September 2015
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Do you define 'handling' as all out grip or progressive breakaway of grip with plenty of feedback as to what the tyres are doing?

As I understand it a low profile tyre will grip better but the transition between gripping and not gripping in a corner is fairly short. With a higher profile tyre there will be a much longer transition due to the extra flex in the tyre wall.

Some folks define handling as all out grip, others look at how progressive the transition is.

Personally I'd go with a higher profile tyre for the feedback it gives while cornering, you can tell when it's approaching it's limits rather than having an oh **** moment. Plus they help soften the ride a little. :-D

Edited by Limeymk1 on Wednesday 9th September 16:25

Dog Star

16,145 posts

169 months

Wednesday 9th September 2015
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F1 cars have high sidewalls. Says it all for me.

gizlaroc

17,251 posts

225 months

Wednesday 9th September 2015
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There is a sweet spot, simple as that.

CO2000

3,177 posts

210 months

Wednesday 9th September 2015
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Dog Star said:
F1 cars have high sidewalls. Says it all for me.
But very little suspension travel...but Caterhams handle better on higher profile too

TA14

12,722 posts

259 months

Wednesday 9th September 2015
quotequote all
gizlaroc said:
There is a sweet spot, simple as that.
Spot on. In the OP's example 14" wouldn't fit over the Ferrari's tyres and people have had to do very extensive suspension modifications to make 40 or 50 year old muscle cars handle well.

Dog Star

16,145 posts

169 months

Wednesday 9th September 2015
quotequote all
CO2000 said:
But very little suspension travel...but Caterhams handle better on higher profile too
But BTCC cars have low profiles..... and no suspension travel
confused

Soupie69uk

924 posts

218 months

Wednesday 9th September 2015
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I think the F1 sidewalls are due to regulations. I think I read that Adrian Newey when designing his no limits F1 car he said he would have a lower profile tyre with a larger diameter wheel. Not sure of the perfect balance though.

jon-

16,511 posts

217 months

Wednesday 9th September 2015
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Soupie69uk said:
I think the F1 sidewalls are due to regulations. I think I read that Adrian Newey when designing his no limits F1 car he said he would have a lower profile tyre with a larger diameter wheel. Not sure of the perfect balance though.
F1 cars are on 13"s due to regulation and "history". Air is a very complex spring, as it's spring rate changes as tyres heat up. All the designers would prefer low profile tyres which would allow them more controllable compliance in the suspension.


unpc

2,837 posts

214 months

Wednesday 9th September 2015
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As a general rule low profiles probably offer more grip than a high profile of the same compound, rolling radius and width(due to less flex) but the high profile one usually breaks away more progressively.

I prefer the ride and handling of bigger sidewalls and they always look better on old cars. Big sidewalls often looks odd on modern stuff though.

otolith

56,212 posts

205 months

Wednesday 9th September 2015
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Define "better".

Probably better to say that they have different handling characteristics which in conjunction with the design and purpose of the car affect their fitness for purpose.

2Btoo

3,429 posts

204 months

Wednesday 9th September 2015
quotequote all
It all depends upon what the rest of the suspension is set up for. Tyre profile is one of many, many factors in the way that a car grips and handles. Lower profile doesn't necessarily mean better or worse handling, but changing the profile of the wheel/tyre on a car without changing a number of other things is not going to do it any favours.

Bear in mind that the world thinks otherwise, and big wheels with rubber-band tyres are de rigeur and seen as desirable by the sheeple. Manufacturers know this and know how to sell cars.

Also, remember that grip is not the same as handling.

kambites

67,593 posts

222 months

Wednesday 9th September 2015
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Assuming I'm allowed to set the damping up to suit, I'd (within reason) go for whatever ends up with the lowest unsprung mass.

mikey k

13,011 posts

217 months

Wednesday 9th September 2015
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kambites said:
Assuming I'm allowed to set the damping up to suit, I'd (within reason) go for whatever ends up with the lowest unsprung mass.
bingo

J4CKO

41,635 posts

201 months

Wednesday 9th September 2015
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handling is one thing, making progress is another, handling is the ultimate use of the car as a whole to get round a corner as quickly as possible, making progress involves being comfortable and not having to pick your way through crappy road surfaces quite as gingerly, so its all a trade off in the real world, also with the likes of SUV's you can see further so that adds into it as well, relative to say being 6 inches off the floor in an Elise or something.

TA14

12,722 posts

259 months

Wednesday 9th September 2015
quotequote all
mikey k said:
kambites said:
Assuming I'm allowed to set the damping up to suit, I'd (within reason) go for whatever ends up with the lowest unsprung mass.
bingo
A tyre of any given dia and width weighs about the same so the smaller wheels will always give the lowest unsprung mass but as mentioned above there is a sweet spot and for the best handling it can be worth sacrificing a little weight for greater grip and control.

otolith

56,212 posts

205 months

Wednesday 9th September 2015
quotequote all
J4CKO said:
handling is one thing, making progress is another, handling is the ultimate use of the car as a whole to get round a corner as quickly as possible
I'd disagree with that. Absolute cornering speed is just one aspect of it. You could have quite high limits and absolutely evil handling, or great handling but not much grip.

kambites

67,593 posts

222 months

Wednesday 9th September 2015
quotequote all
TA14 said:
A tyre of any given dia and width weighs about the same so the smaller wheels will always give the lowest unsprung mass but as mentioned above there is a sweet spot and for the best handling it can be worth sacrificing a little weight for greater grip and control.
Yes there is a sweet spot and it will be different for every person because different people have different priorities. Obviously the more you spend on the wheels, the less weight you add through having larger wheels and hence the sweet spot moves, but with typical OEM wheel materials (pretty much anything heavier than magnesium) for a road car the optimal for me is almost always higher profile than the smallest OEM wheels provide.

I don't think I'd ever want wheels bigger than about 16 inches on a road car unless absolutely necessary for braking performance, and in that case I'd rather go for a lighter, slower car which can manage with smaller brakes.