wide rear tire advantages????

[avgasman]

Agreed.

I'll stick to RWD. Ferrari California, 245/285, 3900lbs, .99G grip.

http://www.motortrend.com/roadtests/...est/specs.html

[Vegas69]

It ain't mid engine...

[Ron.in.SoCal]

Gateano's running 275's or 275/285 (R888 or Hoosier's can't remember which) and he does pretty good....

[avgasman]

It ain't mid engine

47/53 bias at 3900 lbs is still a lot of weight to schlep around.

I think we all agree that balance is key, a 40 -50 mm difference between front and rear is acceptable.

[rfalker1]

My 9.5 I ordered didn't fit, but thanks for all the input it really of everybody. So since they didn't fit my other option was mini tubing, and I didnt want to do that either. So instead I shall invest my money into my next project, a ricer lol. A 1995 to 1998 Supra turbo with a targra top. Please don't hate me for it

P.S so I will be running 255/35's in the rear, and hopefully the extra weight I put in with this sub box shall help gain traction looool.

[Bryce]

Why didnt it fit? The wrong backspace.

[rfalker1]

yep, backspacing was terrible, it would have been way more work than I am willing to have done at this moment for an 1.5 inch difference. I was hopeful

[Paul69camaro]

That sucks that your wheels didn't fit! I'm glad this thread got brought up as I have always been under the impression that wider tires = more traction. However, after going through engineering school I started to think otherwise. This is just my theory and I'm making the assumptions that heat and wear do not play a role in this.

Traction=Friction

Friction= normal force X friction coefficient

Normal force is the weight being put on the tire

friction coefficient is only a function of the two materials, in this case tire rubber and street surface. No where in this calculation does surface area (wider tires) come into play.

I may be missing something but what do you guys think? I'd love to het a straight answer on this.

Paul

P.S. I still love fatass tires!

[6spdcamaro]

That sucks that your wheels didn't fit! I'm glad this thread got brought up as I have always been under the impression that wider tires = more traction. However, after going through engineering school I started to think otherwise. This is just my theory and I'm making the assumptions that heat and wear do not play a role in this.

Traction=Friction

Friction= normal force X friction coefficient

Normal force is the weight being put on the tire

friction coefficient is only a function of the two materials, in this case tire rubber and street surface. No where in this calculation does surface area (wider tires) come into play.

I may be missing something but what do you guys think? I'd love to het a straight answer on this.

Paul

P.S. I still love fatass tires!

I believe the reason this property doesn't apply is because it assumes the contact is between completely inelastic surfaces. Since rubber is a relatively soft material, it flexes and conforms to the road surface, creating a multitude of additional forces holding the tire to the road surface. I believe this is also the reason that softer rubber compounds have more grip. They conform to the surface more than a harder compound would, and therefore increase the holding force with the uneven road surface.

Page 13 of "how to make your car handle" by Fred Puhn covers this. Here is a sample

http://books.google.com/books?id=cr4...page&q&f=false

Hope that helped

[BigBlockOlds]

My 9.5 I ordered didn't fit, but thanks for all the input it really of everybody. So since they didn't fit my other option was mini tubing, and I didnt want to do that either.

Why not sell them, then take detailed measurements and order a set of wheels with the correct backspacing?

[Paul69camaro]

Ken,

Thanks a bunch! If you read right at the end of page 13 and beginning of page 14 it answers my question. The reason wider tires get better traction is exactly due to the reason you stated. Rubber interlocks with the rough road surface, therefore providing a mechanical hold instead of relying strictly on friction between the two surfaces (try to think of it as a gear interlocking with another. I figured I was missing something! I guess it still stands that tire compound is much more important than tire width. Thanks again Ken.

Paul

[rfalker1]

Well I did, I had already bought a thinner set, but wanted the wider ones so basically I had 3 pairs of the same wheels. One 18x8, 19x8 and 19x9.5. So I sent the last ones back and THEN won another set. SO currently in my possession is 4 sets of wheels. The original rally's, the ones on the picture, a set of tvs cadwell. ANd my pride and joy the NewGen I won from driverzinc. ;)

[rfalker1]

Wider Tires + Weight = the possibility of more rubber interacting with pavement, (but it depends on the compound of rubber which becomes the x factor)

Example is when on friction resistant surface such as ice, drivers often decrease the amount of air pressure in their tires to produce more contact between the tire and surface.. thus increasing friction, thus increasing grip.