16 inch wheels?

[NoHachi]

Like I said..to many blanket statements, too many generalisations and some misinformation added in. Tires(which is what we are really dealing with) are difficult stuff..even to trained mechanical engineers. They do not lend themselves well to this kind of pseudo-scientific internet discussions. I'll try and address a couple things I noticed:

Quote:So any area decrease in side wall will only increase stiffness , resulting in everything from laterial stability to less distortion under heavy loads like braking

From memory Kai power , KMS , Pro sprits etc have all found 17" faster on the track but 17" tyres where instantly banned from N2 racing.

I know some racing teams that experienced exactly the opposite.. The interesting question is WHY 17s were faster in some cases and WHY they were banned at all. Were they faster because of the bigger brakes that could fit under them? Superior traction? etc etc.

Quote:larger contact patch Wink

Sorry but you are very wrong. With given tire pressures and vehicle weights, contact patch size is exactly equal for ALL imaginable tires. Think about it. If tire pressure is xx and vehicle weight = yy then contact patch size is always the same and equal to yy/xx. This is one of the most repeated internet fallicies you find. The only way to change contact patch size is to change tire pressures. (which is what they do for example in the desert).

Quote:All well and good having a larger contact patch but by doing that you are reducing the kg/m^3 of them too. So if you use the exact same tyres but in the two sizes then the larger tyre will have a smaller grip per m^3 of the contact patch.

Again this is not correct people. pressure/cm2 is again exactly equal between tires. What does change is the shape of the contact patch. Narrow tires have longer, less wide contact patch that allows rubber particles to stay in contact with asphalt particles longer and allows for more time to squeeze the water out. That is why they are better in the wet.

Quote:I personally would use a high grip, but not too wide, probably roughly stock. Real shame tyre companies do not release the coefficient of friction for their tyres, otherwise you could work all this out easily beforehand.

Not correct. Wider tires actually can produce faster laptimes. For example, they reduce the friction experienced by the car due to turning. I wont go into details as I dont fully understand the elastic and dynamic behaviour of tires myself. Milliken&Milliken has a great introductory section that goes into this. I suggest you read it if you are really interested.
Less friction also means less force required at the steering wheel and less information arriving at the driver. Its all a trade-off..

Quote:Lots of tyre companys release all the information on the coefficient of friction , pressure , temp etc . I have Toyos R888's and they gave me all the information when purchasing them . If you really needing information on the tyre that badly there are lots of companys that do testing , mostly the best are in france.

Almost NO tire company does this kind of testing and releases the results. Whatever information you got with the R888s was most definately a very rough approximation, as true tire/force diagrams are not readable for 99.9% of the engineering community..nevermind the enthousiast.