C-3 tires

[Patrick H.]

Re: Thanks Bill. Anyone else?

Bill,

So why can't you autocross on the Radial TA's?

I've got a set of 215/70 "Performer GT" radials on my car now; these were on when I got it, and I believe are from Western Auto. These are hard as a rock, but allow you some really controlled sliding in an autocross....

I'm looking for something that will stick better as well as ride better than my current rocks.

Patrick

[Bill Baird]

Re: Thanks Bill. Anyone else?

Actually, I don't think it was a problem with the Radial T/A compound. I always attributed the problem to the height of the sidewall (235/70R15). I'll admit I was racing my buddy's '79 (which I've only raced a couple of times), but I couldn't keep that thing under me to save my life (which is not normally that much of a problem, as I don't get that close to the edge when I autocross). But those 235/70's wouldn't let me carry any speed into a corner.

I like my 255/60's a lot better.

Actually, my favorites for autocrossing are the 245/50 BF Goodrich Comp T/A R-1's or their new G-Forces. They're not street tires, but they sure do make one helluva difference in handling. Wow.

Bill Baird

[Duke W.]

DOT wear rating

Years ago our wonderful, thoughtful, and "concerned that we don't hurt ourselves" government in Washington D.C. required tire manufacturers to build all new tires with a "wear rating" number molded into the sidewall to hopefully provide us hapless consumers some indication of tire life. Manufacturers actually have to test all their tires against a benchmark, and it is based on straight road driving. This indication has turned out to be a boon to performance enthusiasts because performance compounds wear faster, so the DOT wear rating has become a surrogate indication of grip. The only reason a Porsche 911 gets a higher skidpad "g" rating than a new C-5 is because the 911 wears rubber with a 140 rating and the Corvette's run flat Goodyears are 300. GM expects the average user to get 30,000 miles from a set of tires. Honda actually got sued by a group of owners over tire wear on the NSX. I'm acquainted with a Honda executive and suggested to him that they need to better qualify their customers and remind them that the NSX is a SPORTS CAR and is designed to provide above average performance and is thus equipped with sticky tires that have an inherently higher wear rate.

The trouble with our Corvettes is that the currently available 60 and 70 series rubber is mostly cosmetic and have very high wear ratings, so they just won't provide much grip. As a general rule of thumb DOT legal racing tires have a wear rating of 100 or less. Serious high performance summer tires are in the range up to about 250 and high performance all season go up to maybe 300. If the wear rating is over 300 you're likely not looking at a serious performance tire no matter how big the white letters might be.

OEMs and tire manufacturers have been smarting from the complaints about tire wear. If you know anybody with a late model 911 you know that they literally have to buy a new set of tires for a thousand bucks, minimum, before the first oil change is due, and this is true of guys who just use them as daily drivers.

Recently released high performance tires generally have somewhat higher wear ratings. The objective nowadays is to improve wear and ride quality while maintaining grip level.

Duke

[Bill Baird]

Re: DOT wear rating

The choice of tires for cars with 15" rims is none too large. I'd love to put some modern high performance rubber on my car, but I haven't found any for 15" rims. When BF Goodrich released the "race" version of the G-Force for 15" wheels, I had hopes that they would release the street G-Force as well in that size, but no such luck.

Maybe I should start looking for some 16" or 17" rims that I could use on my car (a '75) without spacers. I've seen some 17" wheels on a couple of mid-years that didn't require spacers, but they were only 7" wide.

But perhaps I stray from the topic of restoration. :>)

Bill Baird

[Duke W.]

Sticky tire availability

I think you can still get a BFG comp T/A R1 DOT legal racing tire in a 225/60ZR-15, but they might look a little funny on a shark as they are only about 25.5" OD. Also, the Michelin XWX from Coker tire is available in a 225/70VR-15, but they cost about a thousand bucks a set. The next best choice would be the Goodyear Eagle RSA in a 225/70VR-15. It is an all-season high performance tire with a wear rating of 260 and was standard equipment on the old rear drive Caprice police package.

Duke

[Bill Baird]

Re: Sticky tire availability

Yes, I can still get the R1's in the size I like to autocross with (245/50). I like to drive 255/60 on the street (245/50 puts Baby just a little too close to the ground for my comfort). Do they has the Eagle RSA in a 255/60R15?

Bill Baird

[Duke W.]

Re: Sticky tire availability

Don't think the RSA was ever available in a 255/60, and I'm not sure if the 225 70 will be available much longer as most of the rear drive Caprice police cars have been retired. Check Goodyear web site on the referenced URL for the latest info.

Duke

http://www.goodyear.com