Hope this hasn't come up before but here goes anyway...

It might be a nice idea to have the option to adjust the tyre sizes used. Obviously it would need to be within reason, but would add an extra element to racing, especially in single make races. You could choose a wider tyre for extra mechanical grip and be faster in the corners, but have the disadvantage of more rolling resistance and so would slower down the straights.

This might not be a great idea on some of the more powerful cars, as everybody would want to be on the widest available, but on the lower powered road cars it might make a difference.

I know at the moment the different tyre manufactures make no difference, but it could be possible to make certain sizes only available with certain manufactures.

Could even have a choice of wheel sizes, but then we're slipping closer to having "modding"! :smash3d:

This is my first post too, so hello all!

Heya and welcome.

The good news is you won't get flamed for that, the bad news is that it has been suggested before (sort of). Allow me to point out the reasons it's pointless.

Basically, people would work out which tyres were best for which track and that'd be the same setup everyone used. It'd be wide tyres for twisty tracks, narrower for faster ones. If you don't believe me, check out the number of people who use the Inferno car setups - the advantage is lost when the entire field uses the same one.
And then you end up with a full field of cars sharing exactly the same parameters, which is what we have now.

In a similar vein though, the tyres brands may make a difference if and when they're ever added. If one offers more grip but wears out much faster, it'll be a personal preference which you use. Although admittedly not such a big factor in 5 lap public races.

I wonder just how much faster a car with "thinner" tyres goes..........

I wouldn't mind betting than any advantage gained by using thinner tyres, is nowhere near the advantage that wider tyres would give you when cornering, therefore everyone would tend to use the wider tyres and the whole option would become null and void.

Fair points, hadn't thought of that. Must think more!

How about an option of wheels/tyres sizes? Would have to be limited so there aren't people cruising round with 22" rims on a UF1, but if you had a choice of 11" or 12" for example then would you still end up with people still using the same?

Well, I did some braking tests with LFSTweak few weeks ago. Like few cm wide and like half a meter wide tires. Full braking power = locked wheels and there was no difference at all

Quote from Raas89 :

Full braking power = locked wheels

Locked wheels do not stop you faster then rolling ones. Try your experiment without locking the tires. Wider tires are more grippy, and therefore more difficult to lockup. This allows you to apply greater braking pressure without locking the wheels.

Quote from danowat :

I wonder just how much faster a car with "thinner" tyres goes..........

I wouldn't mind betting than any advantage gained by using thinner tyres, is nowhere near the advantage that wider tyres would give you when cornering, therefore everyone would tend to use the wider tyres and the whole option would become null and void.

How much easier is it to ride a road bike on the road, than a mountain bike that's got wide tires?

Wayyy easier.

It is, but you are comparing WAY less than 1 horsepower compared with 100+, TBH, I really doubt it would make much difference, but I am prepared to be proven wrong.

At racing speeds, rolling resistance is about 10% of the total drag on the car. So it would affect laptimes but the car wouldn't really feel any faster. TBH you're going to notice more difference pumping the tyres up than thinning the tyres a little. The extra heat in a thinner tyre could be helpful in cars where the tyres stay cold.

Quote from wheel4hummer :

Locked wheels do not stop you faster then rolling ones. Try your experiment without locking the tires. Wider tires are more grippy, and therefore more difficult to lockup. This allows you to apply greater braking pressure without locking the wheels.

Locked wheels so it would be equal when it slides. Perhaps in real life locked 265-s wide stop you faster than 195-s (With ABS for an example). Dont know about that exactly.
The fact is, wider tires should stop faster, even if locked (like in the little test I did).

Wider tires will stop quicker than thinner ones if they're both locked at the same point. The wider ones have a larger contact patch, and thus, more friction acting upon them.

Of course, not locking will result in a shorter stopping distance anyways :P

Quote from Raas89 :

Locked wheels so it would be equal when it slides. Perhaps in real life locked 265-s wide stop you faster than 195-s (With ABS for an example). Dont know about that exactly.
The fact is, wider tires should stop faster, even if locked (like in the little test I did).

Yes, but the difference in stopping distance between 265s vs 195s while locked is *not* proportional the stopping difference between 265s and 195s that are rolling. When a tire is rolling, there is rolling resistance that also helps you slow down. If you tried your experiment without locking the brakes, the 265s would stop even more sooner then the 195s. If the 195s were on 15in wheels, and the 265s were on 18in wheels, then it might be even.