Racing tire compound

[sierra4000]

Hello All,

what compound affect real tire grip?

is softer compoud really faster?
or depends only on teperature? ( then max grip at ideal temperature is same? )

Thank you for real experiences!

Radek

 

[CapriRacer]

Sierra4000,

To my knowledge, there aren't any rubber chemists that hang out on the internet - I don't know why.

I am not a rubber chemist, but I have worked along side some very talented ones and have picked up a few things over the years. Keep that in mind while I try to answer your question.

When it comes to tread rubber compound, there are 2 things going on. Friction and mechanical grip. Racing tire tread compounds take advantage of both. By being naturally more sticky, and by being softer so the rubber penetrates the macro texture of the pavement. It's this penetrating the macro texture that makes the tire NOT behave according to normal friction theory (grip proportional to the load). That penetration increases the point at which the maximum occurs, but also changes things such that the tire has to get a 10% to 15% slip to generate the max grip level.

So it isn't just softness that increases the grip - and measuring the hardness of the tread doesn't necessarily measure the relative grip level between dissimilar tires.

Temperature? Yes, temperature has an affect on grip and I suspect that both friction and mechanical grip are affected in different ways - and it will be different for different tread compounds.

 

[GregLocock]

I suggest Paul Haney's book

http://www.amazon.com/The-Racing-High-Performance-Tire-Balance/dp/0768012414

It isn't authoritative, indeed some people pick a lot of holes in it, but I think it is a great introduction to the single most important consumable on your racecar.

Incidentally the slip velocity for peak grip is tunable, F1 tires reach peak grip at about 4% slip, otherwise they'd melt.

Cheers

Greg Locock


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[sierra4000]

Thank you very much for responses !

Radek