The future of autox tires?

[OZMDD]

Other than no ability to adjust tire pressures, how do y'all see these in a motorsports setting?

[jrj512]

Hasn't this been around for several years and is still fruitless?

[POS Racing]

NO whitewall option......

[OZMDD]

Yeah, its actually an onld idea, but it appears to be gaining traction (no pun intended) with manufacturers as technology and CAD improves. I'm not expecting to see them anytime soon (and I'd expect them to be cosmetically altered to appear more like a normal tire) but I'm wondering if the experts areound here think they would adapt well to performance applications. They could be made plenty stiff, but would they really handle side-loads properly? Maybe a shoulder would be added to some designs? Just had me thinking...

[cone-cerned]

There was the person who sent ten different puns to friends, with the hope that at least one of the puns would make them laugh. Unfortunately, no pun in ten did.

[Davidss]

I think they would be terrible for motorsports. On a normal tire the contact patch twists to one side under cornering force. The effect is called pneumatic trail and this is what gives you steering feedback. I don't think a tweel could do this very well.

Here is a picture explaining the effect:

[sammm]

This is timely...what are the pros/cons of running 16" wheels/tiresIntead of 17" on equally prepped cars?

[altiain]

The biggest con of running 16” wheels is going to be tire selection. None of the top street tires are available in a 245 width for 16” wheels, while they are all readily available as 245 or 255 widths for a 17” wheel.

[tailchaser]

No shit... Even in the other direction a set of 6ULs + 225/45-15 RS3's will run just slightly more than Bridgestones, the only 16 inch option... Anyone want an extra set of 16" NB OEMs?

[OZMDD]

The biggest con of running 16” wheels is going to be tire selection. None of the top street tires are available in a 245 width for 16” wheels, while they are all readily available as 245 or 255 widths for a 17” wheel.

+1

[sammm]

That sucks.

[OZMDD]

Of course, the 225 size in 16" is probably all you'd want to try to fit onto a stock wheel anyway.

[sammm]

^I am talking stock wheels here (for the NC that is). So if I ran 225/50/16 RS-3's on the 16x6.5" OEM's (15# wheels) versus 225/45/17 RS-3's on 17x7" (17# wheels) OEM's.

Please discuss.

[tailchaser]

the 16 will have very slightly shorter gearing. - 24.9 inch diameter vs 25 for the 17, however that's measured on 7 and 7.5 rims...

[OZMDD]

My vote would be RS3's on the 16's and street tires on your 17's. The lighter wheel/tire combo is significant enough to improve suspension function, and the slightly shorter tire is good with the 5-speed. The 7" vs 6.5" width doesn't seem significant enough to me to justify 3-4 lbs per corner.

The Star Specs in 205/50 or 55 might be an option too, since you have the option to drop down to a 24.1" tire and gain some acceleration. Much narrower tire, though.

For $109/each, its hard to argue with the RS3's. A wide, grippy heat-tolerant tire that lasts forever= WINNING!

[Davidss]

A 6.5 inch or 7 inch wheel is too narrow for a 225 street tire. At most I would go with a 205 on the 6.5 or a 215 on the 7. Assuming the wheels were equal weight I would run the 17 inch combo.

[OZMDD]

There you have it!

David - the 16's are 2 lbs lighter than the 17's.

PS - The MS-R package CS cars (and MX5 Cup cars) run 225's on the stock 17x7's. Why is this too wide? It appears to work well for Slates on street tires.

[Robert]

I think Slates is running 235/40 Dunlops. I am also running 235/40 Dunlops on 7 in wheels in the front. Seems to work, but I don't have back to back testing to really know. I would not try it with R1R's or RS3's, but it seems to work with the star specs.

[sammm]

I always thought it was SCCA legal to "downsize" your wheels/tires from OEM specs, but I'm getting conflicting information.

[Robert]

I don't think it's SCCA stock class legal to downsize.