Duke, et al. Bias Ply Tires...

[Dennis C.]

What is your take on the current "production" or "reproduction" bias ply tires?
This question is not necessarily aimed at early Corvette usage, but simply the use of these tires at all as they might apply to speciality applications. Are they as good as or better than OEM? Are they reasonably safe on the road? What should I be thinking about before purchasing these tires. Thanks in advance... Dennis

[Kevin M.]

Re: Duke, et al. Bias Ply Tires...

Put bias ply tires on your car and get ready to hate it! I only know what I've heard, and it's not good. A friend thought about going through his front end till he switched tires, Alan?

Kevin

[Mike M.]

Re: Duke, et al. Bias Ply Tires...

Why don't ya post this question on the NARS forum (National Airstream Restorers Society). Before ya get tires for the ole aluminum beast, ya best be buying that pretty 51 Nash to tow the AS. The Nash, the Airstream and the dipstick---- what a cute trio. mikie

[Dave Suesz]

Depends on you...

I have OE style "Firestones" on my C1, my Dad always had oversize steel belts on it, I decided to go exact original. I drive the car very little, only to shows and rallys. I also had Mustangs for many years, as daily drivers. They, like any Corvette, respond very well to modern radial tires. If you drive your car frequently, for pleasure, not just a few shows a year, especially if you don't care about points, use modern radials. If you have a C1 or C2, you can get wide whites, redlines, etc. to look the part.

[Ed Jennings]

Re: Duke, et al. Bias Ply Tires...

I had a 66 with repo redline bias ply tires on it. At any kind of speed, it was downright dangerous. On a wet road it was dangerous at low speed. Radials cured the problem instantly without any other modification.

[Joe L.]

Re: Duke, et al. Bias Ply Tires...

Dennis-----

The reproductions are as good, or better, than the originals. They are manufactured just like the originals, but they have the advantage of modern-day rubber compounds (NO ONE can tell this difference by looking at the tire, though). Also, the tires are DOT-approved (that's why they have to have that annoying-to-some little facet on the sidewalls). The originals were not DOT-approved so, from the standpoint of conformance to governmental safety standards, they have that advantage over the originals, too.

Notwithstanding the above, our EXPECTATIONS of how tires should perform have changed DRAMATICALLY since the 60s. So, the ride and handling characteristics of these tires is TERRIBLE by TODAY'S STANDARDS. Even those of us who once rode on 60s tires when they were new (and thought that they were just fine then), would think that they are lousy today.

As far as safety is concerned, they're as safe or safer than the tires we used in the 60s. Is that as safe as the tires we have today? No, it isn't. But, 60s cars aren't as safe as the cars we drive today, either. When was the last time you saw an SIR ("air bag"), anti-lock brakes, or a bladder-type fuel tank on a 60s car?

As a last statement of opinion here: I think that 1960s and 1970s fiberglass belted, bias ply tires were some of the best handling tires ever. They rode hard, but they handled like a dream. These are available in reproduction, too. They were NEVER originally used on a Corvette, but they are "period-correct".

[Dennis C.]

Joe - Thanks for answering the question asked...

I have radials on all 4 of my '62's so this question was not asked to help make a decision on what to put on my cars. However, was curious about opinions on the current bias ply tires from a safety or other (?) standpoint. I drove my '57 way too many miles back and forth across the country w/bias repro tires and am aware of their limitations and charactaristics - which, by the way, are not quite as bad as some would have me believe. Again, thanks Joe.

[Mike Cobine]

Re: Duke, et al. Bias Ply Tires...

As a last statement of opinion here: I think that 1960s and 1970s fiberglass belted, bias ply tires were some of the best handling tires ever. They rode hard, but they handled like a dream. These are available in reproduction, too. They were NEVER originally used on a Corvette, but they are "period-correct".
[i]

Joe, without a yardstick to measure by, many could say that. But in that time period, I was heavily autocrossing (usually every weekend) and some high speed track time. With each improvement in tires (from belted to glass belted to radials and up), the performance did improve. Lap times don't lie. The weight of a steel belted radial made for the general public (most Goodyears and Firestones) compared to a nylon or polyglas radial hurt performance at the limits and was an exception, but was much better in normal driving.

The misconception is caused by the fact that bias-ply belted tires tend to have a flatter curve of the lateral forces to break-away and are a bit more forgiving. A radial, especially the earlier ones, had a harsh break-away at its limits. However, the curve is much steeper on a radial and it gives much higher limits. As such, when it breaks, it has farther to fall. This gave many the impression that a bias-ply tire was much better handling and that radials were unsafe and unpredictable. It wasn't until the '80s that the break-away was much more forgiving and less likely to cause severe problems for the average driver.

Much of that came as people were pushing the radials to the limits in lateral acceleration and demanded an improved tire.

But to compare something like the old Wide Oval to the PolyGlas to a Radial TA is not going to cut it. The Radial TA was so much better. An exception was the Hoosier Street TD in G60 and L60 but then, these were essentially purpose-made tires for autocrossing.

And by today's standards, a Radial TA is a cosmetic performance tire, not a handling performance tire.

Duke has continued to give good advice on good handling tires. If you are going to drive one of these old cars, you should go for the best handling tire you can get. The first reason is that it may just save you and your car one day in a situation your insurance would rather not see. The second reason is you will enjoy it much more in how it handles.

Those old NOS tires, those old survivor tires, and even those reproduction tires are great for the shows. But if tires hadn't improved so much, why isn't the C5 riding on F60-15 Firestone Wide Ovals? For that matter, why wasn't any Corvette after 1973?

[Duke W.]

Re: Duke, et al. Bias Ply Tires...

The current DOT tire standards were written over 30 years ago. A non-speed rated tire only has to be tested to 85 MPH at design load and pressure. It's tough to tell whether today's repro bias plies are better or worse than the originals, but my take is that the repros only meet the absolute minimum DOT standards, which were inadequate even 30 years ago IMO.

My recommendation to anyone who wants to minimize the points loss is to go ahead and buy a set of repro bias plys for the OE wheels, but buy another set of wheels and mount radials with AT LEAST a "H" speed rating so you get the spiral wound nylon cap belt that will keep the tire from disintegrating if there is an internal structural failure. Use the modern radials for driving.

A set of repro 6" Rallys is a good bet for a C2 because you can mount a 215/70 and install the OE wheelcovers. I think you can mount 7" Rallys on a C1 with 225/70s and they will clear the wheel wells. The C1 wheel covers should also snap right on.

Duke

[Loren L.]

Great for hydroplaning.... *NM*

[Loren L.]

This SHOULD be under Dennis' question.... *NM*

[Mike L.]

Re: Duke, et al. Bias Ply Tires...

I purchased NOS 670x15 BSW Firestone for my 64 Coupe about a year ago, and mounted them on my orig. 64 KO wheels. The tires are only good for judging purpose, I wouldn't drive safely on the strees with 40 year old tires.

[Joe C.]

Re: Joe - Thanks for answering the question asked.

Dennis:

I will agree fully with Joe's statement above. In my talks with John Kelsey (the licensed reproducer of Goodyear rubber), he stated, and I am paraphrasing here : 'the reproduction tires are manufactured as good as they were originally, with the exception of the use of modern rubber compounds, which is not scrutinized by the judges'. I think, that he said that the belts are different also (despite what it says on the sidewall), but I could be mistaken here. Albeit, a better tire than original.

Joe

[Joe L.]

Re: Joe - Thanks for answering the question asked.

Joe------

I've been told that new judging standards will include a requirement that a small sample of the rubber from the tires of each judged car will need to be submitted for chemical analysis. Infidels trying to pass off reproduction tires as "original" will have their cars "black-listed" and forever banished from consideration for Top Flight or Duntov award.

[Joe L.]

Re: Duke, et al. Bias Ply Tires...

Duke-----

How do we know that the pre-1968 tires even met the MINIMUM DOT standard applied after 1-1-68 and what guarantee or assurance did we have then that the pre-1968 tires were even safe at a sustained speed of 85 mph?

One other thing that needs to be realized here is that most folks use their tires for STREET operation. For STREET operation, a tire that performs adequately and is safe at speeds up to 85 mph satisfies the needs of about 99% of the drivers, including Corvette drivers. 85 mph is 10 mph over the highest posted speed limit in ANY state that I am aware of. In California, getting caught at over 100 mph gets you taken straight to jail and booked for a misdemeanor (not an infraction as are most traffic citations). It's also a "2 pointer" which automatically takes one out of the category of "safe driver" for at least 3 years (with commensurate effect on insurance rates for ALL the cars one drives).

It's true that higher performance tires will provide better handling at lower speeds than the rated speed and will usually provide much better traction than lower-rated tires. However, once again, most folks never use it if they drive their cars only on the street. I "love" my 1969 WAY too much to expose it (and myself) to the risks associated with "taking it to the limit" (or, even, anywhere near the limit).

My 1992 has Goodyear GSC's, the original tires. These are Z-rated tires that are rated to 149+ mph. Believe me, I've never used them at anywhere NEAR that, and I've never really used much of their "ultra high performance" capabilities, at all in the 40,000 miles that I've put on them. In another 5 to 10 thousand miles they'll need to be replaced and the cost for an equivalent set of Goodyears (the only brand of tire that I use on my Corvettes) will be about $1,000. To be honest, I won't really have gotten that much value from the tires, but I'll replace them with equivalent tires, anyway.

For my 1969, I've used Eagle ST's for years. They're only an "S" rated tire but I like the looks of them. I've been 100% satisfied with them for all the driving that I do with the car and they've never failed me in any situation, at all. I think that they would satisfy the needs of about 99% of the Corvette owners (they're discontinued, though, but there are other similar Goodyear tires available). Of course, these wouldn't be very good tires for someone racing their Corvette at a competitive event. But, how many owners of classic Corvettes do that anyway?