Tire pressure. What psi would be best?

[Robert M.]

I have a couple of questions I'll throw out for disussion on the board.
I have a 1970 convertible with Goodrich TA Radials, size 70/215-15. Now the old 70 owners manual reccomends 24 psi tire pressure for the tires of that era. What tire pressure would you use in the TA Radials, for this car?

The second question: The tires were installed in Sept,1989, and have about 12,000 miles on them, and are in great shape. I've been told they need to be replaced, due to the break down of the compound. That was told to me by a Goodyear dealer. I believe he was looking for a sale. Any thoughts on this?

Thanks,
Bob

[John H.]

Re: Tire pressure. What psi would be best?

Bob -

Most radials like between 28-32 psi for precise tracking and optimum wear pattern (they also like zero-to-1/16" TOTAL toe-in, vs. the 3/16"-5/16" original spec for C3 bias tires). "Compound Breakdown" is a new one on me, unless he's talking about obvious checking, cracks, or casing problems. However, T/A radials are more of an appearance tire than a performance tire (they're not speed-rated), and I wouldn't do anything real wild on 13-year-old tires. I'd probably put new tires near the top of my "things-to-buy-next" list before doing a lot of spirited driving.

[John H.]

Re: Tire pressure. What psi would be best?

Bob -

Most radials like between 28-32 psi for precise tracking and optimum wear pattern (they also like zero-to-1/16" TOTAL toe-in, vs. the 3/16"-5/16" original spec for C3 bias tires). "Compound Breakdown" is a new one on me, unless he's talking about obvious checking, cracks, or casing problems. However, T/A radials are more of an appearance tire than a performance tire (they're not speed-rated), and I wouldn't do anything real wild on 13-year-old tires. I'd probably put new tires near the top of my "things-to-buy-next" list before doing a lot of spirited driving.

[Duke W.]

Re: Tire pressure. What psi would be best?

I would say 32 psi all around for best handling. Tires ultimately harden and age with time and this is accelerated with UV and ozone expose, so if the car spends most of it's time inside, the tires are probably okay for now.

Check the recent archives under "police pursuit tires" if you want a lead on the best currently available tires for your Corvette, or wait a couple of months for my article to appear in The Corvette Restorer.

Duke

[Duke W.]

Re: Tire pressure. What psi would be best?

I would say 32 psi all around for best handling. Tires ultimately harden and age with time and this is accelerated with UV and ozone expose, so if the car spends most of it's time inside, the tires are probably okay for now.

Check the recent archives under "police pursuit tires" if you want a lead on the best currently available tires for your Corvette, or wait a couple of months for my article to appear in The Corvette Restorer.

Duke