Thread: Tires for Boost

these were Kumho 716 ecsta hp4 treadware 360 traction A P195\60615 87H. They were the best all season tire I ever bought. I still use them on my car today. I've had them since I first bought my b14 back in 04. Milage I don't know. These tire were so good in rain and snow. I don't believe kumho makes them anymore.

Well I just bought 4 set of Ziex 912's at 195/60/15 at $248 shipped with 4 valve stems.

Yes I'm serious.

Sure. No problem there. I agree.

Yah, in physics 101. If we chug along to physics 102 or what ever we'll find that there is a whole lot more going on and it doesn't fit nicely into the watered down model given to college students.

You're just stuck in 1st semester physics, that's all. No big deal. There's more to learn.

This is where you're making your error. This is not true. Given the same tire compound, inflation pressure, vehicle weight, wheel diameter, etc. the coefficient of friction (with respect to horizontal and lateral motion) will rise markedly as the width of the tire increases.

There are many, many things at play relating to this topic including all of the factors you mentioned. Tire width is also on the list though.
The confusion comes when people try to apply the simple Newtonian friction model to tires. It doesn't hold true in practice.

Were did you buy them?

DiscountTiredirect.com hehe

Very well said BenFenner.
Now....
WTF. Why are people running skinny tires on turbo cars? Given the same brand and model of tire the wider one will have more grip. Be it on the drag strip, street or track. Simple as that.

My car isnt even on boost and I auto x my car with 225/45/15 tires. I use 195/50/15 Toyo Proxes 4 for daily driving and thats just to help my MPG and the way I drive the extra 1 or 2 MPG is not worth it, Im going back to 205's or 215's.

If youre going to cheap out on the tires and all you wanted was to make your car into a tire smoking machine I have news for you..... EBRAKE . Ive seen so many builds "cheap out" on tires on this forum its not even funny.

You are right, the simple physics I laid forth are not what really happens in the real world. Though friction remains the same without the objects moving, things get a lot more complicated as soon as they do. Friction is a very complicated subject in physics. What I was merely trying to do is get people to think more about HOW a wider tire will give you more grip. This will prevent people from going out and getting a wider tire that don't know what they are doing because someone online told them "wider is better for performance".

A wider tire can provide you with more grip, but for straight line there are alot of benefits of going larger on diameter, rather than wider. Both give you a larger contact patch. Until we get a tire with a compound with a constant friction coefficient over a large temp range, with little tread deflection, having a larger contact patch will increase traction.

I guess I went too far trying to get people to use their brain lol.

Tires have arrived . Will post impressions tomorrow hehe.

Just put some Toyo T1R's 215/45/15 on today. Haven't driven on them yet, but the tire size is closer to the diameter of the stock size, only .3% to fast compared to 205/50 which is 1.3% to slow.

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