iceracer
iceracer HalfDork
11/2/09 6:24 p.m.

Tires for an autocross. Worn to 2-3/32 tread mounted on 5.5" wheel or brand new mounted on a 7" wheel. The 7" wheel widens the track as well. I'm just curious what others think. I know the theory about tread squirm. I'm more curious what the difference in wheel widths would make. Both makes are rated the same as far as performance.

maroon92
maroon92 SuperDork
11/2/09 6:48 p.m.

the width of the contact patch should more than make up for the tread squirm.

Gimp
Gimp GRM+ Memberand Dork
11/2/09 6:51 p.m.

How are they rated? Tread wear rating and speed rating is arbitrary. Compounds can vary even if these numbers match. What makes/models of tire are we talking here?

irish44j
irish44j Reader
11/2/09 9:10 p.m.

depends on the tire in question....

alstevens
alstevens New Reader
11/2/09 9:38 p.m.

Don't forget to consider unsprung weight

iceracer
iceracer HalfDork
11/3/09 9:40 a.m.

Both tires are rated UHP. I didn't mention brands because it is not relevent. The Tire Rack tested and compared both and they are very close. My curiosity is will the worn tire offset the difference in wheel widths and offsets.
I probably will go with the worn tires.

oldsaw
oldsaw HalfDork
11/3/09 10:15 a.m.

In this case, size really does matter.

And the tire size is?

iceracer
iceracer HalfDork
11/4/09 9:25 a.m.

Both are the same size. 205/55x15

Gearheadotaku
Gearheadotaku GRM+ Memberand Reader
11/4/09 9:32 a.m.

7'' is wide for a 205 tire, I'd rather see 6". 215 or 225 would fit 7" better.

If we are talking about the same tire, I'd go with the fresh rubber. Being streched over the wider rim may help with the squirm.

amg_rx7
amg_rx7 Reader
11/4/09 9:51 a.m.
Gearheadotaku wrote: 7'' is wide for a 205 tire, I'd rather see 6". 215 or 225 would fit 7" better. If we are talking about the same tire, I'd go with the fresh rubber. Being streched over the wider rim may help with the squirm.

Huh? 205 is excellent for a 7" wide wheel.

8" is better for a 225-245 width tire.

pinchvalve
pinchvalve GRM+ Memberand SuperDork
11/4/09 10:26 a.m.

This posts assumes that the worn tread has the same advantages as a shaved tread, but is that true? Does wear on the sidewalls, heat cycling, impacts, etc. make a worn tire worse than a new tire?

procainestart
procainestart Dork
11/4/09 12:32 p.m.

I'd rather have a brand new tire than a well-worn tire any day unless the wear you describe is actually from shaving, not use.

To reiterate what amg_rx7 said: a 7-inch rim works great with a 205 tire. A 5.5-inch rim will not support the sidewall as well.

griffin729
griffin729 Reader
11/4/09 12:40 p.m.

The '98-'01 Impreza RS came stock with 7" rims and 205/55 r16 tires. I'd imagine 7" and a section width of 205 should work fine.

Gearheadotaku
Gearheadotaku GRM+ Memberand Reader
11/4/09 1:40 p.m.

Well, my Grand Am had 205/55/16 on 6" from the factory, they fit perfect. My 88 Fiero Formula I had 6" fronts w 205/50/15 and 7" rear 225/50/15. the fit was perfect. No bulging over the rim, or strecting to fit.

iceracer
iceracer HalfDork
11/4/09 6:53 p.m.

The "worn" tires are just that. 3+yrs and 28000 miles. If I felt like changing tires ,which I don't, I would try both. Maybe in the spring when I run on a go-kart track,I will try both.

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