how is tyre grip rated?

[mellonman]

i know alot of us talk about what tyres is best bla bla bla

 

but is there a rating for a tyre with more grip how do you know they are better grip then others?

or is it driver experiance that makes for the tyre choice

 

what is the best road tyre for grip and why?

 

And how do you know?

[dr_jekyll]

its not possible to say imho , so many different variables determan how a tyre grips

[mellonman]

but surely the softer the compound the better the grip,

they must test the resistance at the factory they make the tyre

[SteveR]

Evo had a good, very thorough tyre test a few months ago. The difference between dry & wet grip varied a lot between tyres: i.e. sometimes different brands compared very similarly in the dry, but in the wet, when you compared the same two tyres with each other the difference in performance was exaggerated.

 

Try and dig out a copy - maybe it's online as well?

 

They tested LOADS of things - with the tyres all fitted in turn to the same car so it was fair:, stopping distance in wet & dry, cornering speed in wet/dry, how fast they could drive on standing water before aquaplaning...

[dude]

but surely the softer the compound the better the grip,

they must test the resistance at the factory they make the tyre

 

Not so Gary, a tyre like a 888 will only work if itys up to temp, outside that temp it is hopeless !!! Say on a 1000cc superbike, in the summer on good roads you would run virtual race tyres, in the winter on cold roads a touring tyre will be more predictable and prob have more grip because it is designed to work in those conditions !!! Does that help.

[garethr]

Compulsory tyre labelling is being introduced from November 2012. The categories are fuel efficiency and external rolling noise (neither of which will be of much concern if you're driving a Supra ), and wet grip.

 

http://www.goodyear.eu/uk_en/tire-advice/future-eu-tire-label/

[dr_jekyll]

yes but that same test on a different car may give different results

[SteveR]

yes but that same test on a different car may give different results

?

 

A tyre isn't going to drastically alter it's characteristics compared to another tyre, when both are moved from one car to a different car. I take the point that - for example - a heavier car is unlikely to match the cornering Gs of a lighter car, but the the better performing tyre on one car would - I believe - almost always still be the better performing tyre when fitted to the other car - they won't swap around (unless one or both is operating WAY outside its design conditions, e.g. fitting a moped tyre to a tractor or something equally inappropriate).

 

So in my example, a Caterham might achieve 1G whilst cornering with tyre A on it, and 0.95G with tyre B.

The same brands of tyres (not the exact same tyres because they are probably different width/aspect/radius) are then fitted to a van which repeats the test and the results are:

0.7G cornering with tyre A, 0.63G with tyre B (or whatever the numbers might be) - tyre A is best for cornering G regardless of vehicle.

 

 

I'l wait for someone more informed to come along and say that this is nonsense now

Edited April 4, 2012 by SteveR (see edit history)

[garethr]

I don't know if the labelling will improve matters for consumers, but at the moment it's a minefield:

 

Auto Express - Hankook S1 evo rubbish in the wet

http://www.autoexpress.co.uk/products/total_tyre_guide/259483/hankook_ventus_s1_evo.html

 

EVO magazine - Hankook S1 evo great in the wet

http://www.tyrereviews.co.uk/Article/2012-EVO-Max-Performance-Tyre-Test.htm

[dr_jekyll]

?

 

A tyre isn't going to drastically alter it's characteristics compared to another tyre, when both are moved from one car to a different car. I take the point that - for example - a heavier car is unlikely to match the cornering Gs of a lighter car, but the the better performing tyre on one car would - I believe - almost always still be the better performing tyre when fitted to the other car - they won't swap around (unless one or both is operating WAY outside its design conditions, e.g. fitting a moped tyre to a tractor or something equally inappropriate).

 

So in my example, a Caterham might achieve 1G whilst cornering with tyre A on it, and 0.95G with tyre B.

The same brands of tyres (not the exact same tyres because they are probably different width/aspect/radius) are then fitted to a van which repeats the test and the results are:

0.7G cornering with tyre A, 0.63G with tyre B (or whatever the numbers might be) - tyre A is best for cornering G regardless of vehicle.

 

 

I'l wait for someone more informed to come along and say that this is nonsense now

 

yes but if tyre A operated best at a higher temp than tyre B, tyre A will be at its optimum on an agreesive car that works it tyres up to a high temp wher as tyre B will be over heating . alternatively on a gentle car Tyre B may be running in its opti rage while the previous superior tyre A is under temp so will not be performing

[SteveR]

yes but if tyre A operated best at a higher temp than tyre B, tyre A will be at its optimum on an agreesive car that works it tyres up to a high temp wher as tyre B will be over heating . alternatively on a gentle car Tyre B may be running in its opti rage while the previous superior tyre A is under temp so will not be performing

Hence my hint at the test being done within their normal operating ranges/tolerances, although I perhaps didn't word it very well.

 

Also, they were comparing tyres with the same aim - i.e. sporty performance, it's not like they were comparing a triple8 and a winter tyre.

Edited April 4, 2012 by SteveR (see edit history)

[dr_jekyll]

i uderstand what you are saying . im just saying that different cars work the tyres differently eeven at normal driving speeds and conditions. thats why some people swear by the 452s and other think they are pants. and some love the zz3s and others dont . its all relivant to how your car makes them work

Edited April 4, 2012 by dr_jekyll
many typos made it look like chav txt (see edit history)

[SteveR]

i uderstand what you are saying . im just saying that different cars work the tyres differently eeven at normal driving speeds and conditions. thats why some people swear by the 452s and other think they are pants. and some love the zz3s and others dont . its all relivant to how your car makes them work

Agreed - but arguably what counts when it comes to sporty tyres, is how they are when pushed.

[mellonman]

so with tyres have a small window for optimum heat for grip, which i already know. so there are no numbers on them stating what they are best suited

[JamieP]

I find on my car that brand new tyres of pretty much any make are always very good for grip, soon as they are a few months old i get zero grip no matter how much tread is left on them.

 

Seems soon as they get hot once they are shot, Dyno is the worst, one dyno run and my tyres are rubbish for grip.

[dr_jekyll]

Agreed - but arguably what counts when it comes to sporty tyres, is how they are when pushed.

 

this is true. tyres are a tough one

[SteveR]

I find on my car that brand new tyres of pretty much any make are always very good for grip, soon as they are a few months old i get zero grip no matter how much tread is left on them.

 

Seems soon as they get hot once they are shot, Dyno is the worst, one dyno run and my tyres are rubbish for grip.

Even 888s?

 

I guess it doesn't help that your car needs tying down SO hard.

[JamieP]

Even 888s?

 

I guess it doesn't help that your car needs tying down SO hard.

 

Yup, few months old and they give no grip for my car dyno run or not.

[SteveR]

Yup, few months old and they give no grip for my car dyno run or not.

I knew tyres have generally had it after a few extremes-of-heat cycles, particularly road tyres as I've experienced it, but surprised at 888s having the same problem.

Get some of whatever they put on the Veyron although I think they say they're not safe to use after a bit of very high speed driving, so maybe not if they're no better.

[JamieP]

All tyres are the same, soon as they have had a few heat cycles they are shot, The reason whifbitz use to sell all there R888 part worn time attack tyres, they get hot and go hard.

[Soopra]

i also think a lot of it is driver preference. some people enjoy lighting the back wheels up off every junction, others are not comfortable with this.

 

i bought my current rear tyres because i like the tread pattern (girly moment) but i've found they have much better grip in the wet than my previous tyres (can't remember which brand). Current rears are Toyo Proxes T1R.

[SteveR]

All tyres are the same, soon as they have had a few heat cycles they are shot, The reason whifbitz use to sell all there R888 part worn time attack tyres, they get hot and go hard.

Yeah I guess you're right - the nums used to buy used slicks from F3 teams, dunno if they do any more, but although they were generally 'ok' for half a track day in the UK, Si told me they were no use at the 'Ring (closed rack day) last year. Still, at £100 for 4, why not eh.

[AJI]

When tyre tests are done the technicians would usually fit a g-sensor linked to laptop to record the readings. So from this you can derrive latteral and longitudinal grip levels.

For this to be a direct comparison, as been mentioned by SteveR earlier, you'd have to have the same car but with different tyres on it.

 

To compare one brand tyre on one car versus another tyre brand on another car is next to meaningless.

 

Raw data vs driver opinion can be miles apart sometimes.

[mellonman]

okay how do you know how soft a tyre is before you buy it?

 

i will use gran turismo style rating as a idea

 

S1.... R1

S2.... R2

S3.... R3

 

okay S = sport, R = racing,1-3 being compond (1 being hard 3 being soft)

 

now how are able to know what sort of tyre your getting before you buy? is it just her say

 

There are millions of tyres out there even the top 5 manafacturers have about 10 different types how do you know what is what,

 

i just go into the place and say i have £300 for 2 tyres what you got normally avon zz3 or falkens/continental, there must be a better way

[AJI]

ah, for general buying purposes then you'll need to know a bit more about the tyre in question.

The tyre should have a load, speed, wear rate and traction rating and this should be on the sidewall of the tyre.

 

Speed rating of Y for example is for a tyre capable of 300km/h for 'x' number of minutes. (I can't remember exactly what the value of 'x' is, but I think its around 20mins).

A load rating of between 62 and 126 should see most applications for vehicles you see on the roads today.

Wear rate (tread wear) can be around 100 up to 500 for example - but this is usually manufacturers own ratings, so taking different branded tyres on the same car may see a slightly different wear rate.

Traction rating again is usually manufacturer own rating and can see different effect on the same car. These use AA, A, B, C ratings.

 

 

So basically for doing a Gran Tourismo style comparison you should be looking at Wear rate and Traction rating.

http://rtrdpenguin.hubpages.com/hub/tirebuyingguide

 

http://www.etyres.co.uk/tyres-ratings-nhtsa/tyre-traction-ratings.htm

 

http://www.etyres.co.uk/tyres-ratings-nhtsa/tyre-wear-ratings.htm

Edited April 5, 2012 by AJI
additional links added (see edit history)