Tire Replacement

[Doug L.]

I need to replace the tires on my '64 soon. The existing tires are bias ply but of a non-OEM brand and have the DOT verbage. One also has a cut in the sdiewall.

So I'm reading the 1964 JG to get some direction on what to replace them with. The JG indicates the 5 brands and models of Rayon bias ply tires that were originally available on the car. It also lists 2 brands with models of "Optional" Nylon bias ply tires that were available at that time.

Under "Reproduction Tires" it mentions bias ply in the correct size for the car (6.70-15).

Under "Service Reeplacement Tires" is describes bias and radial construction tires.

What it doesn't tell me is what points are deducted in each case. I imagine having bias ply tires with one of the 5 brands and madela in the correct size and in good condition and meeting all of the other mentioned criteria would receive full points. Since I don't think these are available or if available they would be extreemly expensive and probably unsafe, I am disregarding them.

I'm picking up on the fact that to get some points the tires on the car must be one of the 5 named brands. Now for my questions:
-If I have one of the 5 brands must they also be the named model of that brand (if those models are even available today)?

-Coker Tire advertises bias ply tires in several of the original brands but doesn't mention the model. What sort of point hit would one receive if the car has reproduction bias ply tires in a correct brand but incorrect model, presumnably also having DOT labels?

-Since "Service Replacement" tires are mentioned and radials are included in this category, what sort of points hit will I receive if I have a correct brand in a correct conversion size but in a radial ply tire?

I'd really rather put radials on the car for both safety, ride and handling, but I would also like to know what that choice would do to me in judging verses bias ply reproductions.

I'm certain others ahve been through this decision making process but I have not found such info in the TDB threads. Any help/opinions/advice will be appreciated.

Thanks-Doug

[Alan D.]

Re: Tire Replacement

NCRS has a standard deduction guide for tires relative to originality.
A new "Corvette Judging Reference Manual" is out which I do not have, but from it - Example; perfect except it has DOT is 10%

The first spot I find radial mentioned as a 60% deduct.
Deduct 60% - Current-day OEM brand, service replacement size, bias or radial ply tires or current equivalent sizing designation and correct whitewall width.

[Daniel N.]

Re: Tire Replacement

I'd really rather put radials on the car for both safety, ride and handling, but I would also like to know what that choice would do to me in judging verses bias ply reproductions.

Using radials in an OEM brand, in the equivalent size and with the correct white-wall width (if applicable) is a 60% deduction. I assume that the "equivalent" size means 205/75R15.

Same as above, but in a non-OEM brand, is a 75% deduction.

Everything else (including anything with white walls mounted inboard) is a 100% deduction.

I'm in the process of replacing my bias-ply gold lines with radials. Since I won't have my car judged by NCRS, I went with Firestone FR380 white walls in the 205/75R15 size. The white walls are about 3/4" wide, rather than the correct 1", so I'd get a 100% deduction even though it's an OEM brand. Diamond Back and, I think Coker, convert the Firestones and other brands to the correct white-wall width, but the cost more than doubles. So, for about $550 per set, you can reduce your deduction from 100% to 60% and still have radials.

[Doug L.]

Re: Tire Replacement

Alan, Daniel, thanks for your responses.

If I understand Alan's reply a Firestone bias ply from Coker with "DOT" markings, regardless of model, would only incur a 10% deduction. Maybe I should consider those repros.

Doug

[Bob R.]

Re: Tire Replacement

Before you purchase the tires check the circumference of the tires and the circumference of your tire tub. The Firestone reproduction tires will not fit in the tire tub BF Goodrich will fit they are a little smaller. You should also be aware that these tires are very difficult to balance properly.

[Daniel K.]

Re: Tire Replacement

If you are good with a razorblade, the DOT can be removed.

[Dan H.]

Re: Tire Replacement

Before you purchase the tires check the circumference of the tires and the circumference of your tire tub. The Firestone reproduction tires will not fit in the tire tub BF Goodrich will fit they are a little smaller. You should also be aware that these tires are very difficult to balance properly.

I have the Coker BF Goodrich, fit the tub OK, had to return the Firestones. The diameter should be about 27 1/2 to fit tub. Lots of weights needed to balance, looks tacky!
Dan

[Michael J.]

Re: Tire Replacement

I have been through this on my '66. I chose Firestone SuperSports bias-ply goldline tires that are nylon cord, to minimize deduct (10%), as they still have DOT marks. These tires are terrible for flat spotting, and bad to drive many miles (I put 100+ miles each way to regional). I also see there are polyester cord tires in the same bias-ply, but deduct goes up for them since polyester was not invented in the day of your car, but they are smooth and no flat spotting. Not sure you could find rayon tires, I would suspect nylon is as close as you could get for minimal deduct. Good luck.

[Alan D.]

Re: Tire Replacement

The DOT is not the only tell tale sign of non original tires, something on front also (not sure what it is however)

[Bill C.]

Re: Tire Replacement

Doug; I went for the Coker Firestones on my '63 and found an original spare for the tub. Yes; they are terrible to balance.
good luck
Bill

[Daniel N.]

Re: Tire Replacement

Before you purchase the tires check the circumference of the tires and the circumference of your tire tub. The Firestone reproduction tires will not fit in the tire tub BF Goodrich will fit they are a little smaller.

This comment, of course, applies only to the spare. For judging, the spare does not have to match the road tires. So you could use radials as road tires and have an old bias-ply tire as a spare; I understand that lots of people do that. Fit should not be a problem then, as long as your spare tire carrier bolts match the type of spare tire. (Gold line tires were thicker and require longer bolts.)

[Ken P.]

Re: Tire Replacement

My personal opinion NCRS should only deduct for tires that are over 6 years old. Safety first. Your live rides on your tires.

[Michael J.]

Re: Tire Replacement

My personal opinion NCRS should only deduct for tires that are over 6 years old. Safety first. Your live rides on your tires.

I would agree with your opinion, these old "original" specs for judging are many times encouraging people to take risks with their lives if they drive the cars. One counter to that from NCRS is that you don't have to drive them, so most trailer the cars since they aren't safe to drive very far. My opinion would be to learn some things from other car groups, like MCA. I was an MCA judge for several years, and they have many driven classes, like driven concours, for instance, where safety critical parts, like tires, shocks, etc., are not judged. That makes more sense and actually encourages more people to drive the cars to meets. NCRS just gives you points to offset the use of modern safety critical parts. However, there are members who will risk it anyway to add more points, and that is not a good situation, IMO.

[George J.]

Re: Tire Replacement

Even the Ferrari Club of America doesn't judge tires. The, long time, Chief Judge's motto was "Ferrari's were meant to be driven!". What does that say about us?

George