Grass Roots Motorsports article on plus-sizing!!

[Chris Corolla S]

After reading this, going for 16s or even 17s over a 15inch wheel is looking more attractive (for performance).
Check it out:
http://www.grassrootsmotorsports.com/plustest.html

and one on wheel materials affect on performance:

http://www.grassrootsmotorsports.com/wheels.html

From what I have heard here, going over a 15inch wheel for a small Corolla is not the best for performance (and it sounds like the writers of the article thought the same thing before this test.)
I guess that is not the case?
I think this magazine is respectable, I have read it before and it is very far from rice. 99% of the writers for the mag race cars in some form, and they are focused on SCCA type club racing.

This article might be sticky-worthy....

Chris

[kocho]

I tend to concur with their findings. I read somewhere (can't find the link unfortunately) that on a Lexus IS300 going from 17 to 18 actually decreased performance...

But going +1 or +2 can only make handling better, and comfort and noise just a bit worse.

I wish they had lateral G and acceleration numbers. Plus, it would have been informative if thay had used the same tire width and vary the diameter OR keep the diameter same and varry the width to see what gives the most impact.

Originally posted by Chris Corolla S
After reading this, going for 16s or even 17s over a 15inch wheel is looking more attractive (for performance).
Check it out:
http://www.grassrootsmotorsports.com/plustest.html

and one on wheel materials affect on performance:

http://www.grassrootsmotorsports.com/wheels.html

From what I have heard here, going over a 15inch wheel for a small Corolla is not the best for performance (and it sounds like the writers of the article thought the same thing before this test.)
I guess that is not the case?
I think this magazine is respectable, I have read it before and it is very far from rice. 99% of the writers for the mag race cars in some form, and they are focused on SCCA type club racing.

This article might be sticky-worthy....

Chris

[Chris Corolla S]

They did say it felt like the larger wheels accelerated a bit slower. I also thought it was unfair to use shitty tires on the stock rims, then really nice ones on the plus sized, poor 14inch steelie

[kocho]

Originally posted by Chris Corolla S
They did say it felt like the larger wheels accelerated a bit slower. I also thought it was unfair to use shitty tires on the stock rims, then really nice ones on the plus sized, poor 14inch steelie

Yeah, they said that, but all times are better with the 17" - probably their handling was so much better that it compensated for the decreased acceleration. That's why it would have been useful to get some 1/4 mile or 0-60 or similar results...

[alltrac165]

So we can throw out the first stock tire test as it used a completely different tire type. Then we look at the three oversize combinations. First one uses a 6.5 wide rim with a 195 width tire, second uses a 7" wide rim with a 205 width tire, third uses a 7" wide rim with a 215 wide tire. Unless I'm all wrong on my tire sizes, the tires keep getting wider. So now we don't have a test based solely on tire section height, but on height AND width. I guessing that if they tried a smaller rim with a wider shorter tire, similar results would be had with the bigger rim tests and no loss of accelleration which might have resulted in faster lap times yet. Not exactly a scientific method approach to testing when you change more than one parameter at a time.

[Chris Corolla S]

Well put. Who's to say they wouldn't have gotten the best time of all from a 15X7 wheel.

But still it does show that the taller wheel doesn't really hurt performance that much as long as you increase the width along with it.

[kocho]

Originally posted by Chris Corolla S
Well put. Who's to say they wouldn't have gotten the best time of all from a 15X7 wheel.

But still it does show that the taller wheel doesn't really hurt performance that much as long as you increase the width along with it.

Basically, it depends on the driving conditions. For drag racing in a straight line, big diameter rim would be worse. For slalom - probably not as bad, as there the lateral traction is the prevailing force compared to straight-line acceleration in drag race...

This said, for daily driving (fun driving and some emergency moves), a wider tire with reasonably low profile to provide comfort would be the best compromise IMO

[rezzle]

Just be wary that too low of a profile is just begging for rim or sidewall damage on imperfect roads.