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[SonnyJack]

So, I had grown tired of the PSS (275F/295R/30-19 tires I have had for the past 3 years and decided to try something different. For whatever reason I always had traction issues. Rear end would break loose under heavy 2nd gear acceleration. It was crazy! That was with FBO mods only. Fast forward to now.

I'm supercharged now and knew if I was having traction issues with the PSS with only bolt-ons, I'd be completely screwed with SC'd power. I put my stocks wheels on for the winter (shod w/Bridgestone S04's) and immediately noticed a huge improvement with grip. The S04's in stock size, handled the additional power extremely well.

Now to the point of my post.

It's suddenly springtime out here in the DMV so I decided to go ahead and put my aftermarket wheels back on. Only now I've got the Bridgestone RE-11's! Decided to go 275/305. The grip is positively insane, but the size is what's confusing the hell out of me.

The 305's are considerable smaller than the 295 PSS's, and by smaller I mean by as much as an inch more narrow. I measured them both and the PSS is right at 12 inches while the RE-11's are barely 11 inches wide!

I know different manufacturers could be sized differently, but should a 305 be more narrow than a 295? The pic below is a rear tire which is supposed to be 305/30/19.

Very confused.

[Golddots]

It is very possible for a same size tire of different manufacturers to be a different actual width when mounted. I like to use tire rack's site when comparing specs.

[SonnyJack]

Originally Posted by Golddots

It is very possible for a same size tire of different manufacturers to be a different actual width when mounted. I like to use tire rack's site when comparing specs.

Same sized tire I know to expect a difference, but for the 305 RE 11 to be smaller than the 295 PSS is what's puzzling.

[dparm]

Originally Posted by SonnyJack

Same sized tire I know to expect a difference, but for the 305 RE 11 to be smaller than the 295 PSS is what's puzzling.

Not puzzling at all.

Tire Rack actually shows you the tread width for each size of a given tire. You will see a pretty big discrepancy and it has to do with the sidewall profile.

My 275mm rear AD08R tires have a wider contact patch than most 285mm tires because of their very squared-off sidewalls. Judging by that photo, it looks like the RE-11 has a more rounded sidewall. I suspect that a more rounded sidewall allows for more gradual breakaway at the limits (meaning more predictable handling at the expense of absolute maximum traction).

[SonnyJack]

Originally Posted by dparm

Not puzzling at all.

Tire Rack actually shows you the tread width for each size of a given tire. You will see a pretty big discrepancy and it has to do with the sidewall profile.

My 275mm rear AD08R tires have a wider contact patch than most 285mm tires because of their very squared-off sidewalls. Judging by that photo, it looks like the RE-11 has a more rounded sidewall. I suspect that a more rounded sidewall allows for more gradual breakaway at the limits (meaning more predictable handling at the expense of absolute maximum traction).

Got it. Thanks.

Why is this difference not consistent across sizes? For example, the tread width on the 275 is only 0.1 inch different between the PSS and the RE11.

[JamesGames]

doesnt make sense to me. Per tire rack..

295/30/19 PSS has section width of 11.8 and tread width of 10.7.
305/30/19 RE11 has section width 12.2 and tread width of 11.1.

Both tires are measured by tire rack.