9 rib versus 7 rib tire tread pattern

[Hank H.]

Gentlemen, I have been researching the archives regarding the best reproduction F70-15 tire for a 72 Corvette. The concensus on these prior posts is that the Kelsey Goodyear Speedway Wide Tread is as close as one can get. My question is since these tires have a 7 rib pattern, will I still be subject to a 20% standard deduct. To add a little uncertainity to the issue, the 68-69 JG states that Firestone, Goodyear and Uniroyal all used a 9 rib pattern. Yet in the 70-72 JG, it merely states that original Firestones had a 9 rib pattern. Would this then indicate that by 70-72 original cars equipped with Goodyear tires had only a 7 rib tread pattern? I would appreciate any insight on this as I would like to minimize any Flight judging deductions. Thanks

[Edward J.]

Re: 9 rib versus 7 rib tire tread pattern

Hank, I believe that you are correct Kelsey reproduction tires will have the least deductions. They will get a deduction for the DOT stamp. (10%) I am not sure on the treads design. I do have the Kelsey tires on my 72 and have been only through chaper judging and received 3 points.I have a original spare and believe they look identical as far as the tread design.

[Hank H.]

Re: 9 rib versus 7 rib tire tread pattern

Ed, did not all tires manufactured after Jan 1968 have to have the DOT stamp. Not sure that would be a deduction if the stamp is present??

[Don L.]

Re: 9 rib versus 7 rib tire tread pattern

Hmmm. My Kelsey's have 9 ribs. See attached photo.

I was aware that the Coker/Firestone Wide Oval's had only 7. Are you sure about Kelsey and 7 ribs? I think I took a 3 point deduct for mine. Can check/report back if interested.

Hope this helps.

[Joe L.]

Re: 9 rib versus 7 rib tire tread pattern

Gentlemen, I have been researching the archives regarding the best reproduction F70-15 tire for a 72 Corvette. The concensus on these prior posts is that the Kelsey Goodyear Speedway Wide Tread is as close as one can get. My question is since these tires have a 7 rib pattern, will I still be subject to a 20% standard deduct. To add a little uncertainity to the issue, the 68-69 JG states that Firestone, Goodyear and Uniroyal all used a 9 rib pattern. Yet in the 70-72 JG, it merely states that original Firestones had a 9 rib pattern. Would this then indicate that by 70-72 original cars equipped with Goodyear tires had only a 7 rib tread pattern? I would appreciate any insight on this as I would like to minimize any Flight judging deductions. Thanks

Hank-----


The Kelsey Goodyear Speedway Widetread in F-70-15 size (the size used for all 1968-72 Corvettes) has a 9 rib tread design, exactly like the original Goodyear Widetread tires. You may not be counting the very narrow, outside ribs but those ribs "count".

The Coker Firestone Wide Ovals do have a 7 rib tread count (including the narrow, outside ribs). However, these tires are a fiberglass belted type tire and are not reproductions of the tires actually originally used on Corvettes. They are reproductions of the tires actually used on other cars of the period, but not Corvettes. They are the closest thing that Coker offers in a "reproduction" tire for 68-72 Corvettes, though.

I will offer this, however: a fiberglass better tire will perform better and last longer than non-belted Speedway Wide Tread. Kelsey also sells a reproduction of a period-correct, Goodyear fiberglass belted tire which more-or-less equivalent to the Coker Firestone tire.

So, if absolute correctness is most important, the Kelsey Goodyear Speedway Widetread is the way to go. If some correctness can be sacrificed for better performance and durabilty, then the Coker or Kelsey fiberglass belted tires are the way to go.

[Mike F.]

Re: 9 rib versus 7 rib tire tread pattern

Kelsey tire & Original spare.

[Don L.]

Re: 9 rib versus 7 rib tire tread pattern

Hank-----


So, if absolute correctness is most important, the Kelsey Goodyear Speedway Widetread is the way to go. If some correctness can be sacrificed for better performance and durabilty, then the Coker or Kelsey fiberglass belted tires are the way to go.

Agreed. Frankly, performance would HAVE to be better with the Coker or Kelsey fiberglass than the Kelsey Speedway. Speedway ride/drive is awful. That's why I keep a set of mounted BFG Radial TA's too. If you look closely at Mike's tread pic, you can (kinda) see that the Kelsey tire has a bit of a crown to the tread surface. The original tire is flat in the same area. Might that be why the Speedway reproduction is so difficult to handle and rough in ride? These repros seem to find EVERY imperfection in the road's surface.

FWIW, I checked last year's judging sheets. I lost 3 of 30 originality points and 0 of 30 condition points for my RWL Speedway tires. Great for photos. Not so much for driving...

[Joe L.]

Re: 9 rib versus 7 rib tire tread pattern

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Agreed. Frankly, performance would HAVE to be better with the Coker or Kelsey fiberglass than the Kelsey Speedway. Speedway ride/drive is awful. That's why I keep a set of mounted BFG Radial TA's too. If you look closely at Mike's tread pic, you can (kinda) see that the Kelsey tire has a bit of a crown to the tread surface. The original tire is flat in the same area. Might that be why the Speedway reproduction is so difficult to handle and rough in ride? These repros seem to find EVERY imperfection in the road's surface.

FWIW, I checked last year's judging sheets. I lost 3 of 30 originality points and 0 of 30 condition points for my RWL Speedway tires. Great for photos. Not so much for driving...

Don-----

Don't forget the Kelsey tire pictured is NEW; the spare is FORTY YEARS OLD. Things can change in 40 years. I expect that's the difference between the tread curvature of the new tire versus the old. I don't think this curvature has anything to do with the problems you describe. These tires were always the way you describe. Radials did not years ago virtually completely replace bias ply tires because the bias ply were just as good.

While the Coker or Kelsey fiberglass belted tires will perform better than the Speedway Wide Treads, don't expect a comfortable ride from either. Fiberglass belted, bias ply tires were years ago the best handling tires I ever had on my 1969 Corvette but they were also the roughest riding tires I ever had.

The combination of ride and handling of high quality, modern radial tires far surpasses any old bias ply tires. Most folks today have either forgotten how bias ply tires rode or never experienced it in their lifetime. Back in the 60's we thought they were great but only because we didn't know anything else.

[Terry M.]

Re: 9 rib versus 7 rib tire tread pattern

Gentlemen, I have been researching the archives regarding the best reproduction F70-15 tire for a 72 Corvette. The concensus on these prior posts is that the Kelsey Goodyear Speedway Wide Tread is as close as one can get. My question is since these tires have a 7 rib pattern, will I still be subject to a 20% standard deduct. To add a little uncertainity to the issue, the 68-69 JG states that Firestone, Goodyear and Uniroyal all used a 9 rib pattern. Yet in the 70-72 JG, it merely states that original Firestones had a 9 rib pattern. Would this then indicate that by 70-72 original cars equipped with Goodyear tires had only a 7 rib tread pattern? I would appreciate any insight on this as I would like to minimize any Flight judging deductions. Thanks

Ed,

I believe you are reading something into the juging manual which just is not there. Plese cite the edition and page number of the 1968-69 manual which says all three brands of tires have 9 ribs.

Are you a member of the Carolinas Chapter? I just received a question (and responded to it) from Reba Whittington asking a remarkably similar question on behalf of a fellow member.

[Don L.]

Re: 9 rib versus 7 rib tire tread pattern

Joe:

Every new/repro Speedway that I have looked at has a crown to the tread while every original (including my WSW spare F/stone Wide Oval) has a flat tread profile. I've paid attention to this, thinking that weaker/different belting may be contributing to the lousy handling on the new tire.

I never experienced original bias ply handling/ride. Missed it by just a couple years, but I just can't imagine (but I do believe you) that what I have today was the norm then. Wow!

Has anyone compared regular duty performance from a set of original bias ply tires to the same version in a set of reproduction tires?

[Hank H.]

Re: 9 rib versus 7 rib tire tread pattern

Terry, I am a member of the Carolinas chapter and was the source of Reba's question. The 68-69 JG on page 33 (Third edition) states that "Original Goodyear, Firestone , and Uniroyal tires had nine ribs on the tread".

For some reason, perhaps the Kelsey photos of the Speedway Wide Tread, I thought they were being reproduced with only 7 ribs. If they have nine, then that is what I will purchase for judging. I would like to have a judging tire that is also decent for a PV that I will attempt at Kissimmee. I have a set of old Firestone 9 ribs that flat spot terribly- a very bumpy ride for 5-8 miles. Do you think that the Kelsey Goodyears will be better inasmuch as the rubber compound will be new? I only need them for judging and PV. I have radial tires and wheels for normal driving.

Thanks to all for your responses. The board never ceases to amaze me with member willingness to help on any issue.

[Don L.]

Re: 9 rib versus 7 rib tire tread pattern

My Kelsey Speedway Wide Treads flat spot - same as your Firestones.

[Joe L.]

Re: 9 rib versus 7 rib tire tread pattern

Joe:

Every new/repro Speedway that I have looked at has a crown to the tread while every original (including my WSW spare F/stone Wide Oval) has a flat tread profile. I've paid attention to this, thinking that weaker/different belting may be contributing to the lousy handling on the new tire.

I never experienced original bias ply handling/ride. Missed it by just a couple years, but I just can't imagine (but I do believe you) that what I have today was the norm then. Wow!

Has anyone compared regular duty performance from a set of original bias ply tires to the same version in a set of reproduction tires?

Don------


Keep in mind one important thing about every original Goodyear Speedway Wide Tread you've seen: every one of them is about 40 years old and suffers from the same age-induced changes. Now, if we could find, say, a 1 year old original tire we'd have a good basis for comparison. However, I think I can safely say we're never going to find a 1 year old original tire.

[Terry M.]

Re: 9 rib versus 7 rib tire tread pattern

Terry, I am a member of the Carolinas chapter and was the source of Reba's question. The 68-69 JG on page 33 (Third edition) states that "Original Goodyear, Firestone , and Uniroyal tires had nine ribs on the tread".

For some reason, perhaps the Kelsey photos of the Speedway Wide Tread, I thought they were being reproduced with only 7 ribs. If they have nine, then that is what I will purchase for judging. I would like to have a judging tire that is also decent for a PV that I will attempt at Kissimmee. I have a set of old Firestone 9 ribs that flat spot terribly- a very bumpy ride for 5-8 miles. Do you think that the Kelsey Goodyears will be better inasmuch as the rubber compound will be new? I only need them for judging and PV. I have radial tires and wheels for normal driving.

Thanks to all for your responses. The board never ceases to amaze me with member willingness to help on any issue.

Hank,

I have never experienced any of the reproduction tires first hand as a driver, but I am sure I was a passenger in many Corvettes with both Firestone and Goodyear reproduction tires. All the tires I own are Goodyear Wide Tread RWL and they are all 40 or more years old. One is even one of the original five that were put on the car at St Louis. I do know that many PVs have been run on both the reproduction Firestone and Goodyear tires, but I do not know how old those tires were -- except I am sure they were not 40+ years old. The PVs I did the years I was National Team Leader (about 1987 to 1999) were mostly on Firestone reproductions because the Goodyears only became available in the last year or two of my service. The times I noticed flat spotting, it went away before the end of the road test and I regarded that as typical of OEM tires. I can assure you the original Goodyears, which I have had a lot of first hand experience with, flat spotted something awful -- especially here in the Northland where the driving season is only six months long.

I don't have my 1968-69 TIM&JG here in Altoona, but I will check that wording when I get home. If it says what you quoted, not that I doubt you, I will be eager to see what the "new" manual says. Thanks for bringing this to our attention.

Edit add: If I were doing PV now days, and I am not -- or at least I haven't for a decade or so -- one of the first things I would check is the date code on the tires. If I found 40+ year old tires the PV would be a fail at that time. I would not put my butt on the line with 40+ year old tires. They are fine for judging, but not PV. Of course that is just my two cents, and since I don't do PVs any more (I don't even think I am on the list any more) my opinion is about worthless.

[Mark D.]

Re: 9 rib versus 7 rib tire tread pattern

Here is a pic from Ralph Spears showing an NOS Firestone tire tread pattern...