dyhppy

why would bald tires not grip really well on dry ground? isn't there more traction than with tread? on water, different story.

kane.s2k

If your tires are completely bald the odds are that the steel layer is about to show and steel on pavement will not have much traction.

dyhppy

not talking about that wore. talking about tires not at the triangle wear bars yet.

slimjim8201

My rears are right at that limit right now and I can tell that they are noticeably more "twitchy". Granted, it's been pretty cold out, but they don't seem nearly as secure as they did over the summer.

DimaK321

i think that the rubber is of a different composition throughout the tire

also, i think that the compound just starts to dry-rot

Street Ghost

Different compound of rubber between the "bald" layer and the tread blocks.

bky

Yes, the rubber at the base of the tread is much more rigid than the outer layer. This is needed to provide dimensionally stability to the tread blocks. On most tires, this layer of rubber doesn't grip as well.

The short answer: the compound is different.

dyhppy

now i get it. thnx

Nobody

Not sure about the compound being any different. I believe on most tires the compound is the same--when the tire is fresh. The difference is that by the time you get to where the tire is a slick it's been heat cycled through 10,000, 20,000 or more miles, which 'cooks' the rubber and makes it harder....so by the time you get down to the good stuff, it's hard as asphalt (Yokohamas, I've found, are particularly sensitive to heat cycling and get less and less grippy as time goes on). If you were to take any tire, shave all the blocks off so there's no tread, you'd have a tire that's stickier than a treaded one by the same proportion to how much 'space' is taken up by the grooves. This is why we shave our RA1s--or any other DOT approved R compound tire. Of course, if you shave 1/2 the tread off you get basically half the life. RA1 Toyos are typically stickiest when they're almost corded after being shaved to 4/32nds (they get stickier as they get heat cycled to a point.

A couple years back DavePK ran his S2000 at Thunderhill in the OTC on shaved Sumitomo HTRs and pulled times people only dream of on street tires.

sahtt

For any of or all of the above reasons, I've had very poor traction with bald(er) tires. At the time, I was thinking the same sort of logic. In my 400rwhp z32 turbo, I had some very low tread kumo's on the rear. I would get loose much easier on my 1->2 shift than once I got new yoko's.