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Tyres: Compromise between grip and durability.
osdecar - 27/5/13 at 11:52 AM

Hi everyone!

I'm a Spanish young engineer attempting to design a "LeMans style" locost proto. (Like Radical or Funyo cars)

Now I am in the early stages of the suspension design and I am searching for the correct tyre to fit in the car. But I am a bit lost because I have not much knowledge about commercial tyres specs. I have searched in the forum about this topic, but I haven't found anything. Sorry if this is not the place to make ths question!


So,

I estimate the car will weight around 600-800 kg and it will have around 200 bhp. The car will race always on track and only with dry conditions. And I am seraching for a tyre with good grip capabilities but specially with a long longevity (I am not rich enough to change a whole tyre set each trackday!! haha).

I have several possibilities in my mind, but I am plenty of doubts.


Street/circuit Tyre (e.g. Toyo R888): They will have a good grip, but, How many km/miles will they last? Will they get on temperature with a lightweight car?

100% Circuit tyres: Superb grip, low longevity, high price, designed for lightweight cars.

-Avon radial-slick: around 600km each set and 240€ (in Spain) per tyre.

-Hoosier R6: The same price as tha Avon... Longevity?



There are much more options, but all of them fall into one of this two groups.

Can someone with experiences with this tyres help me to make a decission? How long do the Toyo last? And the Hoosier? In terms of longevity/price, Does it worth the difference between the Avon and the Toyo?




Sorry if my english is not the best of the world, if you don't understand anything, please tell me!!



Greetings

[Edited on 27/5/13 by osdecar]

[Edited on 27/5/13 by osdecar]

snakebelly - 27/5/13 at 03:05 PM

You should also consider the race series that you propose to aim the car at as most will dictate what tyre you can use anyway.
The R888 has no problem getting up to temp opn a light car but you will have to run considerably lower pressure than you would typically expect when using them on the road, also bear in mind that the R888 is available in different compounds, the medium compound is road legal but the softwer compound isnt if i remember correctly.
also consider that you may want to also spec a rain tyre as R888's in the wet may not be your best choice. The MSa bluebook, the uk bible for motorsport, lists tyres suitable for use and also seperates them into categories which most uk race series publish as their allowed tyres. see here:
Linky
HTH

[Edited on 27/5/13 by snakebelly]

snakebelly - 27/5/13 at 03:07 PM

List 1B is the usual one used for your type of vehicle.

Bare - 27/5/13 at 05:47 PM

Erm.. Race tire compounds have a time limit AND a heat cycles limit.
Unlikely... either... will outlive a summer season's use.

osdecar - 27/5/13 at 06:01 PM

quote:
Originally posted by snakebelly
You should also consider the race series that you propose to aim the car at as most will dictate what tyre you can use anyway.
The R888 has no problem getting up to temp opn a light car but you will have to run considerably lower pressure than you would typically expect when using them on the road, also bear in mind that the R888 is available in different compounds, the medium compound is road legal but the softwer compound isnt if i remember correctly.
also consider that you may want to also spec a rain tyre as R888's in the wet may not be your best choice. The MSa bluebook, the uk bible for motorsport, lists tyres suitable for use and also seperates them into categories which most uk race series publish as their allowed tyres. see here:
Linky
HTH


quote:
Originally posted by snakebelly
List 1B is the usual one used for your type of vehicle.


Thank you for your answer snakebelly!

At the moment, I am not aiming any racing series, I just want it for use it during trackdays. But one of the things I have in mind about the choice, is to find a "standard" size just to be able to change the tire without modifying the suspension characteristics.

Of course, I don't think in the R888 as a tyre for wet conditions, I just think about it because, as it is a road tyre, I think it will wear less than a 100% track one. A R888 without pattern would be great! But, I think it doesn't exist, does it?.


I am very please to hear that R888 will get to temp in a light car!


Thank you very much for the link! It will be really useful! But I still have the same problem... ¿How long do that tyres last? ¿How many km will they have a reasonable performance?



quote:
Originally posted by Bare
Erm.. Race tire compounds have a time limit AND a heat cycles limit.
Unlikely... either... will outlive a summer season's use.


I am not sure if "only" a summer season is long enough for a trackday car... I wouldn't like to spend 1500€ each 6 trackdays just in tires.


Just to have an idea, how many trackdays could I have with the Toyo R888?? And with the Hoosier R6??

[Edited on 27/5/13 by osdecar]

Custardpants - 17/6/13 at 04:04 PM

With a weight of 600kg my medium R888s have half their tread left after at least 5 Trackdays and about 5000 road miles. The light weight of the car was the biggest factor on this. Personally I've found the Yokohamaa A048 to be far more resistant to running at a hot temperature compared to R888s, so an A048 at a softer compound would be recommended from me. Medium compound R888 tyres need to get up to past 60degrees C to start working properly - nothing worse than buying tyres which never warm up enough. With medium compound you should be okay in the warm Spanish temperatures though - in the winter I can't get my r888s hot enough.