C32 AMG, C55 AMG (W203) 2001 - 2007

Traction Gains

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Old 03-10-2009, 05:51 PM
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cdd
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Traction Gains

I've searched, but can't seem to find an answer to my question--but I know it must have been asked before. Here goes...

Are there any appreciable traction gains when one moves from the 7.5/8.5 staggered OEM wheel setup to 8.5/9.5 staggered that most forum members run?

I'm assuming yes, since you're increasing your contact patch--but I don't know if the benefit is noticable or not.

If I did buy new wheels, I'd probably stay with 18s.

Thanks in advance for the info.
Old 03-10-2009, 06:11 PM
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As long as you have a good wide tire you will be fine with both setups. And its not like u can go with a wider tire on a 9.5 since the stockers can house 265. For a stock car 265 is the max anyways otherwise u have rubbing issues.
Old 03-10-2009, 07:19 PM
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Originally Posted by cdd
I've searched, but can't seem to find an answer to my question--but I know it must have been asked before. Here goes...

Are there any appreciable traction gains when one moves from the 7.5/8.5 staggered OEM wheel setup to 8.5/9.5 staggered that most forum members run?

I'm assuming yes, since you're increasing your contact patch--but I don't know if the benefit is noticable or not.

If I did buy new wheels, I'd probably stay with 18s.

Thanks in advance for the info.
Hey cdd,

How's it going? Bolded section above is a common misconception. Contact patch does not increase as you alter wheel width, nor does it increase if you mount wider tires. You do wind up reshaping the contact patch, however (i.e. wider, but shorter).

Last edited by c32AMG-DTM; 03-10-2009 at 07:33 PM.
Old 03-10-2009, 09:13 PM
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you'll probably get more traction jsut buy getting stickier tires like some michelin ps2's then switching to wider rims. Or you can get a lsd.
Old 03-11-2009, 01:10 AM
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I'm about to buy PS2 as well... Test drove a car with PS2 and it was fannntastic.. They wear off way too quick though..
Old 03-11-2009, 09:15 AM
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Originally Posted by c32AMG-DTM
Hey cdd,

How's it going? Bolded section above is a common misconception. Contact patch does not increase as you alter wheel width, nor does it increase if you mount wider tires. You do wind up reshaping the contact patch, however (i.e. wider, but shorter).
Hey man--doing well. Just passed 16K on the clock last night...

Regarding the tires, you're right--that does seem a little counterintuative.

So riddle me this. If someone was to put a widebody kit on their car and were able to get 315s on the rear wheels--they would have the same amount of rubber on the ground as with 265s?
Old 03-11-2009, 09:46 AM
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Originally Posted by cdd
Hey man--doing well. Just passed 16K on the clock last night...

Regarding the tires, you're right--that does seem a little counterintuative.

So riddle me this. If someone was to put a widebody kit on their car and were able to get 315s on the rear wheels--they would have the same amount of rubber on the ground as with 265s?
LOL... you've gotta drive that thing more!

Yes, if the same model tire, same psi, same load on the tire (i.e. vehicle weight), the surface area of rubber on the ground should be approximately the same. The contact patch rectangle gets wider, but decreases in length. That's not to say that "wider" isn't important - all things equal, it should corner, brake, and wear better (and probably accellerate better, if wheel spin is an issue with the narrower size).

TemjinX2's right, you'd probably notice a bigger difference going to an overall stickier tire. A plus-zero wheel fitment can improve handling if it's a wider wheel and/or lighter wheel - you're just not necessarily putting "more rubber to the ground" if that makes sense...
Old 03-11-2009, 10:50 AM
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Originally Posted by cdd
So riddle me this. If someone was to put a widebody kit on their car and were able to get 315s on the rear wheels--they would have the same amount of rubber on the ground as with 265s?
Plus if you went to a really wide tire, you may have problems with it heating up sufficiently, thus loosing traction overall.
Old 03-11-2009, 03:19 PM
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The wider tire overall will quite possibly have a higher load rating, which means that you can safely run a lower tire pressure. The tire manufacturer should be able to reccomend a tire pressure for a corner weight.

The other thing is that traction is not only from static friction, or hysteresis. There is also an adhesive friction which comes into play more when the tires heat up. So a greater contact patch, although there will be less ground pressure, is still beneficial.

Of coures, the most effective way to increase traction is to change tire compounds, but then you sacrafice tire life.
Old 03-17-2009, 12:25 AM
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Originally Posted by cdd
Are there any appreciable traction gains when one moves from the 7.5/8.5 staggered OEM wheel setup to 8.5/9.5 staggered that most forum members run?

I'm assuming yes, since you're increasing your contact patch--but I don't know if the benefit is noticable or not.

If I did buy new wheels, I'd probably stay with 18s.

I'm going to answer this in a very straightforward way. Moving up an inch in wheel width is more for looks than traction(even if tire width is increased proportionately). This has pros and cons though...

Pros... Cooler look. Slightly larger contact patch(not much of a pro)

Cons... Increased wheel and tire weights. Greater rolling resistance. Decreased RWHP(if larger wheels are used).


If it's traction you're going after, you're looking down the wrong path. Either switch to a softer compound tire, or increase your tire DIAMETER instead of width. Sidewall height is where traction comes from, not width.


HTH.

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