Tires - Revisited

[Stuart F.]

Things in the aftermarket C-2 radial tire market have changed and, somewhat, have passed me by because I hadn't felt a need to be in the market based on my normal driving these days. A recent happening, however, woke me up to my complacency. First, let me premise this by saying my current set of tires are Goodyear 205/75R X 15 Regattas that I put on back in 2002, and the've served me well for my type/style of driving. I have regularly checked their tire pressures and looked for any signs of dry rot or damage. I no longer do any long stints of highway driving (nothing longer than 20 miles or less, and no sustained high speed runs or redline bursts. I know I should be looking for something to change to (my last), even though these tires have no more than about 10k miles on them. My wake up call came this last week when I switched cars around in my garage in order to change an overhead fixture. When I returned the Vette to it's bay every thing looked fine. A few days later I noticed my right front tire was flat. I quickly jacked the car up to take weight off the tire to lessen the distortion on the bead. I inspected the tire for any noticeable puncture, but saw none. I then attempted to put air back into the tire and soon noticed a leak out of the side of the valve stem. On closer inspection, I had to conclude it had just failed due to probable dry rot or perhaps from a too close to hubcap abrasion.

So, a word to the wise like me who may be putting off that new set of tires because of all the reasons I mentioned above. It's not just the tires baby!

So, that being said, in my usual few words; what's available out there these days that I should consider and budget for?

Thanks in advance for your valued advice.

Stu Fox

[Ed S.]

Re: Tires - Revisited

Stuart,

Thanks for sharing your experience - you (and we) learn something new every day. And since you asked......if you don't already have them, a battery shut-off switch and a good hefty fire extinguisher would be very prudent investments. Actually, get 2 fire extinguishers. Keep one in your Corvette at all times and mount the second in your garage near a door that you can safely exit through if a fire starts and you decide not to fight it.

[Carmen R.]

Re: Tires - Revisited

Stuart,

When you get a chance, check these guys out. I believe they just released or are about to release radial tires that have shoulders that look like bias ply tires. If that's not important to you, they also carry white wall radials that look like radials. Their tires are based on modern tires made with modern molds.

http://www.dbtires.com/aboutus.html

[Michael J.]

Re: Tires - Revisited

Tires are something that you do need to check regularly and replace ever 6-8 years, IMO. and valve stems just foretell what will soon happen to the tire itself. The newer tires don't seem to last as long as the older ones did, I still have the original tires from my '81 Corvette stored and they look great and have never lost air, but have no weight on them. Today the typical C2 tire of 205X75X15 is not popular so the choice is limited. I have seen Goodyear, Hankook, Kumho, and Uniroyal in those sizes that run from about $65 to almost $100, I think the "T" speed rated ones are the best. You can find them at Walmart or on Tire Rack.com. The DiamondBack radials are great, but they are also very expensive, but have better selection in tread and sidewall looks. Good luck.

[Dan D.]

Re: Tires - Revisited

Thanks for the wake-up call. After reading this thread, I realize that my tires have been on for 15 years. Even though there arn't that many miles on them and they look fine...that doesn't mean that the rubber isn't somewhat degraded. I think I'll buy a new set of "shoes."

[Stuart F.]

Re: Tires - Revisited

Thanks for the responses. I agree, it is time to change and the valve stem probably was a good warning. I probably should go with a better speed rating as it doesn't take long for an SHP like mine with a 3:36 final to exceed the century mark.

Ed; thanks for your advice. I do not really take safety too lightly even though I am a product of the old generation that looks back and wonders how we survived - both in our cars and in the jungles of SEA. I do have a knife switch battery disconnect, and an array of fire extinguishers both in my cars and home.

Thanks again fellows.

Stu Fox

[Duke W.]

Re: Tires - Revisited

Did you change the valve stems with the last new set of tires?

This is very important, especially on cars that accumulate mileage slowly, and the life of the tires and valve stems is ultimately limited by age rather than miles, and wheel covers should always be installed with the valve stem in the middle of the wheel cover valve stem slot. If the valve stem is contacting the wheel cover, pull it off and try again!

I'm not aware of any 205/75R-15 tires that are speed-rated higher than T, so they all lack the spiral wound nylon cap belt that are nearly universal on H and above speed-rated tires. That's why I call them "van tires". I think the same may apply to the 225/70R-15 replacement size for C3s.

There are a few 215/70R-15 tires that are H-rated, but they are all off-brands that you've probably never heard of before. Check www.tires-easy.com for some examples.

I'd never heard of this place until, on a lark, a few years ago I searched for a set of 225/70R-15 102V Firestone PV41 police pursuit tires that had been out of production for at least a couple of years. I did a google search on those exact words and most whose Web sites said they were available came up empty when I called and asked them do a physical inventory check... all except this place, which is out of Portland, but I think my Firestones shipped out of their warehouse in Montana. They must have been the last unsold set in the country, and I would have bought more that four if they had more than four in stock.

Another choice in Corvette replacement sizes is the Avon CR6ZZ DOT legal racing tire. They're expensive, and will likely only last about 10,000 miles of normal street driving, which may be a decade or more, but their adhesion is far beyond what you've ever experienced with a conventional road tire.

Duke

[Michael J.]

Re: Tires - Revisited

Another choice in Corvette replacement sizes is the Avon CR6ZZ DOT legal racing tire. They're expensive, and will likely only last about 10,000 miles of normal street driving, which may be a decade or more, but their adhesion is far beyond what you've ever experienced with a conventional road tire.

Duke

[Duke W.]

Re: Tires - Revisited

Michael - what's the tire size and wheel width on the Shelby?

Duke

[Michael J.]

Re: Tires - Revisited

Those were 215 70R15s on a 7" rim.

[Duke W.]

Re: Tires - Revisited

It's odd that the Avon data sheets on the CR6ZZ list both the 205/70R-15 and 215/70R-16 having the same inflated OD of 26.65". This is slightly less than the 27.0" for most 215/70s, but greater than typical 205/70s. They also list revs/mile as 757, which is based on the "rigid body" calculation and does not take into account loaded deflection, which increases the rev/mile figure about three percent, which would be about 780 compared to typical 215/70s' 775, so it should not have a major impact on speedometer accuracy.

I emailed Avon through their Web site asking for a clarification of the 205/70R-15 OD - perhaps it is an error - but they never replied.

OA width for the 215/70 is speced higher than the 205/70 as is the tread width, which is a whopping 7.5". For this reason I don't think the 215/70 will fit on a C2 without fender interference, so assuming the 205/70 OD is correct, that would be the one to choose.

They are sold by Roger Kraus racing up in Castro Valley, CA... nice guy, I've talked to him at vintage races.

If one decides to by a set of these Avons ask Roger to measure the circumference of both the 205/70 and 215/70. Of course since the tires are not inflated, it will be a little less than spec, but if they both measure near the same (about 6.9 feet) then the 205/70 is probably the best way to go. It's speced at 6.61" tread width, so it's certainly not skinny.

Acceptable wheel widths are 5.0 to 7.0", so it should be okay for any OE C1 or C2 wheel.

The 225/65R-15 or 245/60R-15 should be okay for all C3s.

BTW, all the sizes I mentioned are V-rated and the UTQG rating for all is 80AB. The B temperature rating is because these tires are actually designed to retain heat. Optimum tread temperature for maximum grip is probably 180-200 degrees, but you won't be able to obtain or sustain this temperature range on the road, but even at more moderate temperatures they will stick like glue.

The spec sheets are available from the Roger Kraus Racing Web site or here:

http://www.avonmotorsport.com/historic/historic/cr6zz

Duke

[Michael J.]

Re: Tires - Revisited

I really like the Avons, I also have a set on my '64 FIA Cobra, very sticky tires and since I don't drive many miles a year, I don't know what my tread life will be, but probably long enough. I live about 1/2 mile off a paved road up an arroyo that has sand and gravel in it, and I have to go very slow as it is easy to hear all those projectiles being thrown up into the wheel wells. That is one caution with these tires, you need paint protection from gravel and sand chips behind the wheels.