Another tire question

[Kenneth H.]

A simple question. I'm going to replace the incorrect bias ply tires on my LT1 with RWL radial tires. I want a tire that looks fairly correct for the '70 LT1 and comes close to the specifications laid out in the Judging Guide for replacement RWL radial tires.

Originally I was considering the BF Goodrich Radial T/A, but I just spoke to their support line and they tell me that the Radial T/A sizes that they make won't work for my application (the P215/70R15 and P225/70R15 can't be mounted on an 8" wheel and the rest of the sizes don't come close to the JG specs). However, I've seen a number of 'vettes with these tires mounted. I'm wondering how that's possible.

I've read all of the threads and also reviewed the Restorer articles and still can't figure out what to buy. Anyone have any advice on which tires to use?

Thanks

[Pat M.]

Re: Another tire question

I have RWL P225/70R15 Goodyear Eagle GT IIs on my 70, and I think we have the same wheel size. I really like them, but I didn't have the car judged with them.

[Robert E.]

Re: Another tire question

Ken, I have a set of P215 70R15 B.F. Goodrich RWL tires on my '71 with 8" rims. They fit just fine.

As far as judging is concerned, B.F. Goodrich wasn't available for 70 or 71, I do believe the choices were Goodyear or Firestone. Also, radials weren't factory equipped until 1973 I believe.

I have a second set of Goodyear F70-15's I use for judging and use the Goodrich tires for driving.

Robert

[Patrick H.]

Re: Another tire question

I have 215s and 225s on my cars. I'd go with the 225s if it were me. And despite what the high school dropout on their tech line says, both sizes fit fine.

FYI, when the JG gets revised next I'm going to try and "put in a plug" to allow 215 or 225 as a "proper" replacement size. The 215s (which are in the JG now) are being phased out of many tire lines, and actual tire size measurements should allow the 225 since in some aspects it's closer to the originals.

Patrick

[Jim T.]

Re: Another tire question

I have had 255/60/15 Goodyear Eagle GT's on my 1970 for a lot of years. I am pretty sure I will replace them soon with 255/60/15 Goodyear Eagle GT II's.
Hope I have as good service life from the GT II's as I have had from the Eagle GT's.
I liked the look of the profile of the 255/60/15's when they were an option for the 78 Corvette and like the wider tire on my 70.

[Jamie F.]

Re: Another tire question

I put the Diamondback redline radials on my car. They don't say anything on them, they are blank, just the redline.
They are the correct size and if you go with the Uniroyal tire the tread looks very similar to the original bias ply.
I haven't had them judged yet, but the 68-69 guide is pretty vague on replacement radials, as it only states "correct", but doesnt call out what is correct, except for maybe Goodyear or Firestone?
So maybe someone could chime in and tell me what will happen with my tires. A deduction for no brand? but correct strip and size?

[Patrick H.]

Re: Another tire question

I put the Diamondback redline radials on my car. They don't say anything on them, they are blank, just the redline.
They are the correct size and if you go with the Uniroyal tire the tread looks very similar to the original bias ply.
I haven't had them judged yet, but the 68-69 guide is pretty vague on replacement radials, as it only states "correct", but doesnt call out what is correct, except for maybe Goodyear or Firestone?
So maybe someone could chime in and tell me what will happen with my tires. A deduction for no brand? but correct strip and size?

Per page 21 of the JRM 7th Ed, odds are that the tires would be a 60% deduction if Uniroyal supplied tires in 1969, or more likely 75% because I don't think they did (don't have a 69 JG handy).

[Kenneth H.]

Re: Another tire question

Guys, thanks for all of the input. It looks like I have a few options for tires. My first choice originally was the BF Goodrich Radial T/A P215/70R15 tire, which seemed to be closest to the "OEM dimensions" as specified in the JG and pretty close visually to the original nylon tires. However, based on the comments, I think that I'm going to go with a P225/70R15 tire, either the Goodyear Eagle GT II or the BF Goodrich Radial T/A. They both seem to be a little better fit for the wheel, aren't that far off from the JG OEM dimensions and will probably be more readily available in the future if I ever need to replace one.

Thanks

[Jamie F.]

Re: Another tire question

Patrick,
Well what if they are blank and don't say Uniroyal or anything on them?
And why is there a section on Radial Replacement Tires if they are a 60-75% deduction anyway?

[Patrick H.]

Re: Another tire question

Patrick,
Well what if they are blank and don't say Uniroyal or anything on them?
And why is there a section on Radial Replacement Tires if they are a 60-75% deduction anyway?

1. If they don't have a brand name on them that identifies them as an OEM supplier, then it doesn't matter what brand name is or is not on them. They're 75%-ers at best.

2. There is a section because so many people have radials on their cars. It then provides the judges with something to go on, and gives owners a chance at Condition points rather than a full deduction. You need to have 10% of the origianlity points to get any on condition.

Other than for a trailer, the last new bias ply I bought was ... never. I did buy 1972 tires for my 72, but that's different.

Patrick

[Jamie F.]

Re: Another tire question

Understand Patrick, Thanks.

[Jamie F.]

Re: Another tire question- Weights Actually

While were on the subject of tires I noticed in the T.I.M.&J.G. that it states wheel weights were never installed on the outside of the rims?
Is that true?
A true balance needs weights on whichever side is called for. I would be suprised if they only mounted weights on the inside for the sake of appearance or ease of trim ring installation???

[Chuck S.]

Re: Another tire question- Weights Actually

While were on the subject of tires I noticed in the T.I.M.&J.G. that it states wheel weights were never installed on the outside of the rims?
Is that true?...

True. A near-perfect balance requires weights on both sides, but the weights on the outside would have interfered with proper fit of the trim rings. A marginally good balance can be obtained with weights only on the inside.

For judging, go with the reproduction Goodyears if you can't stand the point deduction. The best, but expensive, solution is to have one set of wheels/tires for judging, and another for driving.

[Duke W.]

Re: Another tire question

Static balance can be achieved with weights on only one side of the wheel, but the assembly can still be dynamically unbalanced, which can cause it to "wobble", and this is usually evident by a back and forth wiggling of in the steering wheel at certain speeds.

Dynamic balance became more important as tires and wheels got wider, and nowadays, virtually all new cars have wheels/tires that are statically and dynamically balanced, so you will see weights on both sides.

It's easy to obtain dynamic balance and OE appearance by using stick-on weights inside the wheel drop center as far to the outside as possible and OE type flange weights on the inside flange.

Modern balance equipment allows the operator to measure and input the distance of both inside and outside weights from the circumferential centerline of the wheel, which is necessary for the machine to compute the correct weight for spot-on static and dynamic balance.

Duke

[Michael M.]

Re: Another tire question

Ken,
According to the Summit catalogue these are the specs on severel tires.
Coker Firestone Wide Oval F70-15 O.D. 26.9 width 6.5
B.F.G. Radial T/A P215/70R15 O.D.26.9 width 7.0
P225/70R15 O.D.27.4 width 6.7
The T/A's suggested rim size is 5.5-7.0 in. for the 215 and 6.0-7.5 in. for the 225's . I have 215's on my 71 and they run fine.
The Firestones rim size is 6.0-8.0.,hope this is of some help.
Mike Markley (42753)