how old is too old for radial tires?

[Terry M.]

Re: how old is too old for radial tires?

Avon sells car tires in the US, but there are not too many distributors or dealers.

https://www.universaltire.com/avon/2...hite-wall.html

Do some more googling.

Roger Kraus Racing in nothern California sells the Avon CR6ZZ DOT legal racing tire, which has sizes suitable for vintage Corvettes with OE wheels.

Duke

I will have to Google some more -- this time away from work.

That V101 on the tire you cited is exactly what is on the OEM Goodyear RSAs that I have used for the last decade or more. Same tire I set the cruise on triple digits on the way back from Breckenridge Regional some years ago. They wear like iron, but don't work so well in the snow. But then if I wanted a M&S tire lots are available - that part is easy. If I had those Avons instead of breaking my window for the Garmen I would find the car on blocks one morning. Ah, the joys of urban living. At least some cultures still value the large four-door sedans, even if for nefarious purposes.

[George J.]

Re: how old is too old for radial tires?

Why do you need new tires? IIRC your Z-rated Pirelli P4000 Super Touring tires have only been on your car for a few years.

Do you let it bake in the sun all day and store it in a sealed garage at night full of a bunch of ozone producing electric motors?

Duke

Duke,
mine are coming up on 10 years old. I figure I have a few years left, but I want be proactive about this. I don't think a 235 will fit my '65. I would be worried about a 225. Does anyone run a 225 on their midyear? I know different tires have different heights, but would a 225/65 give about the 27.4" diameter we need?

George

[Duke W.]

Re: how old is too old for radial tires?

Ten years isn't that old for high speed rated tires that don't bake in the sun all day. The newest tires I have on my cars are Z-rated Dunlop Sport 8000s on the '88 Merc. They are in excellent condition and get a thorough visual inspection at least once a year, which is usually no more than 1000 miles from the last inspection.

The largest tire that will go on a C2 with an OE wheel and no more than minor, if any, interference is 215/70R-15. Anything wider or significantly taller could cause significant interference problems.

225/65s are shorter, wider and have higher revs per mile than 215/70s. You should be able to find specs from any manufacturer that offers this size and compare to 215/70s, which are approximately 27.0" inflated OD and are rated at 775 revs/mile.

The Z-rated P4000s disappeared and then reappeared a few months ago, so you should check availability and consider ordering another set to store until they are needed.

Duke

[George J.]

Re: how old is too old for radial tires?

Duke,
correct me if I'm wrong, but isn't the correct size for a midyear 215/75? I don't have my car at the office, so I can't check, but I thought that was the size I have and the speedometer works perfectly. I think the height of these is 27.4", which is what we need.

George

[Duke W.]

Re: how old is too old for radial tires?

You won't find 215/75R-15s other than "van tires", plus they're too tall; 215/70R-15 matchs the OE 7.75-15s in terms of inflated OE and revs per mile - about 27.0" and 775.

Earlier 6.70-15s are about 27.4" and 760 revs/mile. GM did not change the speedo gearing with the 7.75s. They just accepted the two percent high side error.

If you want to mount a cheap set of radial tires to push it around the parking lot, the closest size to OE is 205/75R-15 which splits the difference between the above OE sizes with a revs/mile spec of about 766.

Duke

[Joe L.]

Re: how old is too old for radial tires?

You won't find 215/75R-15s other than "van tires", plus they're too tall; 215/70R-15 matchs the OE 7.75-15s in terms of inflated OE and revs per mile - about 27.0" and 775.

Earlier 6.70-15s are about 27.4" and 760 revs/mile. GM did not change the speedo gearing with the 7.75s. They just accepted the two percent high side error.

If you want to mount a cheap set of radial tires to push it around the parking lot, the closest size to OE is 205/75R-15 which splits the difference between the above OE sizes with a revs/mile spec of about 766.

Duke

Duke------


I believe that 195-75-R15 is the generally accepted "equivalent size for 6.70-15 and 205-75-R15 the generally accepted "equivalent" for 7.75-15. As you mention, one is not going to find either size in anything that resembles a performance tire or, even, any tire that would be appropriate for a Corvette.

[Duke W.]

Re: how old is too old for radial tires?

I certainly don't accept that premise, but I recall that some JGs erroneously specify 195/75R-15 as a dimensionally close size to OE, but 195/75R-15s are both shorter and have higher revs/mile than any of the two OE or two replacment sizes I mentioned and provided the inflated OD and revs/mile data.

I don't have exact data for 195/75R-15 in my files so I checked that size at Tire Rack and they don't have any, so it appears this metric radial size has joined the ranks of discontinued tire sizes, which does't surprise me because it was somewhat of an oddball size that very little OEM use.

Duke

[George J.]

Re: how old is too old for radial tires?

You won't find 215/75R-15s other than "van tires", plus they're too tall; 215/70R-15 matchs the OE 7.75-15s in terms of inflated OE and revs per mile - about 27.0" and 775.

Earlier 6.70-15s are about 27.4" and 760 revs/mile. GM did not change the speedo gearing with the 7.75s. They just accepted the two percent high side error.

If you want to mount a cheap set of radial tires to push it around the parking lot, the closest size to OE is 205/75R-15 which splits the difference between the above OE sizes with a revs/mile spec of about 766.

Duke

Duke,
I apologize. I don't know why I was thinking my tires were 75 series. They are the 215/70. I wasn't searching for the Pirelli's since I thought they were officially discontinued, but since there seem to be some sources, I'll purchase those. Maybe in a year or so, but it certainly gives me a better feeling that they are available. It would be a shame to have to put non-performance tires on my car. It would start me seriously thinking about keeping the car, and that makes me break out in a cold sweat.
I appreciate your patience and help, as always!

George

[Duke W.]

Re: how old is too old for radial tires?

If you can find a set of Z-rated P4000s I recommend you buy them now. They may be gone in a year and not come back.

Duke