Tires, Bias Ply or Radials

[Guest imported_scotties1]

On our 53 Special 45R that we just purchased, we have bias ply tires (H78-15 )with the wide (3 1/2" )white walls. The car tended to follow the ruts ( grooves )in the road so we took it in and had alignment done.....cars still wants to follow ruts but not as bad.

Our question is do these tires seem to be the correct size and if switching over to radials will straighten the ride ?

We know you can't get the same look as the bias ply but we are more concerned with safety.

Thank you.......Scotties1

[our51super]

By all means get the radials. Teresa and I had a '57 Cadillac that had bias ply on it and we had to anticipate turns 3 miles in advance and if there was a groove in the road we just went in that general direction - it was bad. We have used nothing but radials and the control and ride improves dramatcally. So, unless this is a 400 pt car that you trailer to shows for trophies only, I would strongly suggest you put on some radial tires and enjoy a nice safe drive.

You can go to www.coker.com for more tire info. They have a bias-to-radial conversion table which really helps out.

Cheers!

[our51super]

The H78-15, according to the coker site, is equivalent to a P235/70R15. The white wall is 2 3/4 inches.

Hope this helps!

[Ron Green]

My 55 Pontiac did the same wandering as your 53. It was almost impossible and very dangerous to drive. It had a older set of bias tires of which I replaced with a new set of bias tires from Universal Tires from Hershey. It now goes straight as an arrow even with a heavy continental kit hanging over the rear end. It seems that the newer bias tires are made from a better compound then ones that were made not to long ago?

If you keep the maximum amount of air (less roll) in a new bias tire it will keep the vehicle from wandering all over the road if everything else (steering, etc) is properly adjusted. Tires that started with a letter such as your H-78 I think are for a 60's vehicle? My bias are 7:10-15.

[Dave@Moon]

This is one of the oldest and most contentious subjects on the forums. Here are just a few of the comments on this subject I've posted in the last few years:

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Novaman's diagrams <span style="font-style: italic">(note--this thread comntained a diagram, now lost, showing how bias ply treads are squeezed together under the stress of the car's weight--radials remain in contact with the road surface regardless of direct or angular stress)</span> are a great explanation of the relative unsafeness of bias ply tires. There needs to be a few things further pointed out, however.

First, the diagram showing the shifting of the tread pattern off of the ground in a turn, while illustrative of that problem, also illuminates what I feel is the bias ply tires' greatest weakness. The sideways force on the tire from turning that results in the lifting of tread from the road also occurs when you use these tires on uneven surfaces. Anyone old enough and unfortunate enough to have experience driving with these design tires over street car tracks or worn brick roads (especially in the wet) can testify to how squirrelly a car's handling can be.

I know I've personally been in cars with bias ply tires thrown several feet sideways when suprised by poor road conditions (they do change both over time and space) at highway speeds. The last time that happened to me (in 1989 Pittsburgh's Fort Pitt Tunnel's then worn bricks in the wet @ 55 mph) I swore I'd never drive bias plys again. The only bias ply I've owned since the day after that incident has been hanging from a tree in my back yard for my kids.

Another very important consideration is illustrated in the bottom of Novaman's posting. It shows how, even when sitting still on a perfect level surface, the treads of a bias ply tire are squished together by the forces applied to them from the diagonally biased cords. Has anybody out there ever seen a Goodyear Aquatread advertisment? Can you imagine what happens to the water channelling capacity of the tread pattern when the treads are compressed and deformed in this way? It is not a cooincidence that tread design technology essentially stalled for 50 years while the bias ply tire was the standard of the day!

Incidentally, this deformation of the tread under load is widely believed to be the reason why bias plys do not have the tread life of radial tires.

I'd love for this to be a simple academic argument for me. I don't own a trailer, either to pull the car or for the car to pull 5 extra wheels around with me to shows. My cars occasionally do encounter situations that would compromise my and my family's saftey if they were driving on bias plys, sometimes by very small degrees and sometimes by quite large degrees. I'm not willing to do that, f%&@ the 15 points!

Especially when there are radial alternatives that require very close examination to determine that they're in fact not original equipment. (Here's a simple question: if it were legal to produce a "B.F. Goodrich Silvertown" that looked 100% original but was in fact of radial construction, who'd know and who'd care? )

There was a time when seat belts, sealed beams, external mirrors, turn signals and the like were also considered to be nice but unnecessary for a "reasonable" degree of saftey. And cigarettes used to aid digestion, too.

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The only advantage of reporduction bias plys is the precise physical similarity the original equipment tires (lettering, tread pattern, etc.). They are made of materials that differ substantially from the originals in composition (usually for the better) and are rarely the product of the manufacturer named on the sidewall.

If it were legal to produce a radial construction tire from the reproduction/original molds used by Coker and others, so that perfectly servicable radials were available that exactly mimicked the external appearance of the old bias plys (i,e, B.F. Goodrich Silvertowns, etc.), who'd notice or care?

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We have available today from numerous sources radials that duplicate the external appearance of older model bias-plys in every aspect. You can get wide-whitewalls, red/blue/gold lines and the like from Coker Tire, Universal, and most of the other antique tire marketers.

My final thought on the matter is that the reproduction tires purchased from these outlets are immitations, anyway. They may be made from the original molds, as some are. But (I believe) none of them duplicate the original composition of the rubber material, or use vintage sources for the cord and belt materials in the tires. To do either would make for an even less safe product. Why are they preferable to correct appearing radials in any way?

To say that these reproduction bias-ply tires are the best/most authentic pieces resonably available is very little different from saying the same thing about modern-fiber carpeting or plastic reproduction taillight lenses. (Neither of which I advocate accepting, by the way.) Therefore, where is the import of their use? Is this the best argument that can be presented on behalf of a less than ideally safe component being employed in a car that is expected to be driven?

Tires are a saftey related wear item. They deserve to be treated differently than batteries or seat fabric.

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These are links to three of the largest discussions on this subject we've had (two here, one on the AACA side) that have survived the numerous format revisions the forum has had:

http://www.aaca.org/ubbthreads/showflat.php?Cat=&Board=UBB2&Number=36802&Forum=UBB2&

http://www.aaca.org/ubbthreads/showflat.php?Cat=&Board=UBB2&Number=35207&Forum=UBB2&

http://www.aaca.org/ubbthreads/showflat....=UBB1&Words

Research these, and most sides of this issue will be apparent.

[jerryacheson]

I have a 59 Impala with bias tires and it scares me to death. I feel like I need 2 blocks to stop it and it follows 'the groove' as well. I'm orderning my radial WWW tires from Diamond Back Classic Tires at www.widewhitewalltires.com

They custom made my 1" WW radials for our 62 Electra and they look and ride very nicely. They're a little cheaper than Coker too. I'm ordering the radials for my 59 today. The Impala takes 2 1/4" ww which is not listed on their website. Email or call them and they'll make exactly what you need. Enjoy!

[Guest brh]

When I was getting my 65 back in shape to drive to shows I went out and bought new radials. I know its not right for the car but if I'm going to drive it I want the traction. I showed the car and lost 4 points (spare is correct). When some idiot slammed on his brakes at 55 mph and I had to hit mine, I stopped. Left a lot of rubber on the road but my prize was not damaged. To me safety is the biggest issue and that includes protection of my car.

[Jyrki]

There was a thread on the HAMB board regarding radial WWW's. People claim that the Cokers and Silvertowns turn brown or grey rather quick, and you cannot keep them white. However, everyone seemed to agree the Diamondbacks are of high quality, and cost less than the others. The Silvertowns are actually not made by Goodrich, but a Mexican brand. Diamondback uses Dayton radials and vulcanize a separate whitewall on it.

[our51super]

I don't have any experience with Coker but Teresa and I bought Diamondback tires about 2 years ago and they balanced well, no shimmies, etc., and the white walls are still as white as they were when we first got them. I would recommend them.

[our51super]

Here's their web site if anyone is interested:

http://www.widewhitewalltires.com/widewhite.htm

In other news: Teresa and I are about 4 weeks away from having a little Crin or Teresa JR. Great! A helping hand around the garage. I've been practicing: "Go get daddy the 9/16".

Cheers!

[Guest imported_scotties1]

Hello & thanks to everyone for all of the the information.

From all of the posts to this subject both public and private I have decided to go with radials. Will keep you and the forum informed as to manufacturer.

Thanks also to the Buick Club for making this site available.

Many Blessings and A Happy Holiday Season...........Al

[Guest Shaffer]

My grandfather's 55 Buick had bais-ply WWW tires, and while they looked great on the car, it also "followed the grooves", or crowns in the pavement. On the interstate they was fine even @ 80 mph. I think a 50s or very early 60s car has to have WWW's in order to look original. Not only the WWW's, but the look of the tire and tread itself look good on the cars. I think some cars used bais-ply cars until the late 70s. We had a 1977 Plymouth station wagon back in the late 1980s-early 1990s, and I remember the original spare in the spare tire well, being a "belted bais-ply" tire. I think Lincoln was the first to offer radial ply tires in about 1970-1971.

[NTX5467]

Radials were optional equipment as early as about '68 on Buicks and probably other GM uplevel cars. Ford was deep into Michelin as a radial tire supplier for the full size LTDs and others in '69.

Chrysler kept belted bias ply tires longer than anyone although radials were an option in many cases in the early '70s, but made the Goodyear PolySteel (a.k.a. "Bigfoot") radials pretty much standard in '74 on everything. The alternative for them was the PolyGlas belted tire back then in some cases as the dealers had alignment problems with some radials they didn't have with the previous bias belted tires and declined to order radials as optional equipment as a result. As with GM and Ford, the higher level car lines had radials as standard and the smaller cars had them as options, but that changed about '74 when everyone had radials on everything.

Enjoy!

NTX5467

[Stripgear]

My 2 cents.

1) Radials are superior to bias ply.

2) Bias ply are more sensitive to misalignment problems than radials

3) I find the bias ply tires work just fine in my '48 Super. The problem is

finding someone who KNOWS OLD CARS AND BIAS PLY TIRES! I had the same

problems as everyone else until a found an older gentlemen to align my car.

Most shops today just are just not familar with bias plys and old cars.

[Guest my3buicks]

Radials first became available on Buicks in 1967, although there was a brief period in the early 70's (1972 for sure, not sure of 71) that radials where not available from Buick. Can't say why they dropped them in 72(and possibly 71), but maybe it stemmed back to the alignment problems. Anyone have this answer?

[NTX5467]

Thanks for verifying the "earliest model year" on that, Keith. I was hedging a little when I said it was about '68 as I didn't have a judging handbook close by.

Now that you mention it, I don't recall seeing where radials were available in the early 1970s years you mentioned or that many GM cars with them back then. At that time, everyone was still leaning toward fiberglass belted bias ply tires for most vehicles. Might have been a price issue or possibly that radials were perceived to be too expensive for the added benefits when compared to the "hybrid" belted bias ply tires.

Pontiac did their "Radial Tuned Suspension" in about '73 or so and that probably started the radial tire push that culminated with the new GM Spec Radials being standard equipment on all GM vehicles starting with the 1975 model year (along with catalytic converter emission systems), touted as the "GM Efficiency Package" as I recall.

Enjoy!

NTX5467

[old-tank]

The earliest radials made for American cars were terrible! In 1972 I bought a set of Gates radials for my 1971 Olds 88...never could balance those suckers and the over-steer and "tail wag" took some getting used to. I then put on a set of Firestones and still could not balance even after truing and spin balance on the car. Happily went back to bias-belted.

Later I bought a 76 Olds 88 that came with the GM spec radials (BFG) and still balance problems (but the oversteer was better) until I put on MichelinX.

Now I buy a set of quality radials and computer balance and forget until replacement.

If you bought quality bias ply tires when they were all you could buy (1960?) they were probably better than any that are currently available. All of the technology(?) and manufactuing effort was focused on making good tires. Also the roads 30-40-50....years ago were much wore than those that we drive our collector cars on today. Coker tire BFG's are probably the best that are current available.

If I could I would change the slow ratio steering and the puny sway bar on my 55's before changing to radials. A few years ago the radial tires on my 76 Olds were "ice-picked" on the side walls and while waiting for my insurance company to investigate and pay I put on a set of 7.60 www intended for one of my 55's and the ride and handling were not much if any changed.(that car did look like a pimp-mobile with www)

A few more observations:

Bias ply are still common on large trucks

If you want radials, put them on after you rebuild the suspension, not instead of rebuilding.

Willie

[Guest]

Radials were introduced by Michelin in the mid-50's, so were around for much longer than some posters think. GM did not use them as OEM equipment until 15-20 years later, but that's not surprising.

[Guest Shaffer]

My old 72 Electra still had the original spare tire in the trunk. I think it had something like "poly-glass" on it somewhere, but not 100%. It was definetly a bais-ply tire. Also, my parents old 1976 Lincoln Town Car they had back in the 1980s, also had the original spare tire, and it was a radial. I would say you are right about Chrysler keeping bais-ply longer than anyone else. As I mentioned before, our old 1977 Plymouth stationwagon had the original spare tire and it was a bais-ply.

[NTX5467]

PolyGlas was the name that Goodyear put on their fiberglass belted bias ply tires. This construction was a hybrid which combined the beneficial zero degree belt to stabilize the tread (from the radial) with the more conventional bias ply casing. It stabilized the tread for better handling and traction and longer tread life while keeping the more conventional manufacturing machines around for a bit longer. As I mentioned, they were a transition tire.

When the P-Meteric radials came online, they were lighter weight tires than the previous radials. The P-Metrics were designed to run higher pressure (35psi instead of 32psi) and do so without a severe penalty in ride smoothness and impact harshness compared to the previous radials. In those earlier times, a typical H78-15 or HR78-15 would weigh about 29-30 pounds. Now, a P225/75R-15 will probably weigh about 25 pounds. Comparing the two tires, most of the weight removal has resulted in thinner sidewall areas. Also, by my observation, the tread of the current radials is not as stiff as the earlier ones. Lean on a current unmounted radial and the tread on the flat surface will probably buckle upward from the force. With the earlier radials, the tread flattened out and didn't buckle upward, letting the sidewals take the flex as they were designed to do in earlier versions. Bias-belteds acted like the later radials did, but pure bias ply tires would let the tread buckle inward.

Therefore, Willie, it doesn't surprise me that you had the results you did while using your vintage tires on a late model vehicle, with respect to ride and handling on probably dry pavement conditions.

In those earlier times, using the bias ply as a baseline, the bias-belted tires rode smoother and rolled easier than the bias ply tires did, with the glass belt radials (as opposed to steel belt radials) being a little smoother with better handling due to the stiffer tread and softer sidewall that seemed to be what a radial was all about. The Michelin steel belt radials were the primo tire, with Michelin's history going back into the earlier parts of the 1900s in France.

The earlier radials had "belt" issues too. You could have a car that would align and drive straight with a set of bias ply or bias-belted tires and when a new set of radials was installed, it suddenly would pull one way of the other. Alignment would be to spec, but to get them to drive straight again you had to alter the caster to make it drive straight again. This drove the alignment guys crazy and caused many bad words to be said about lower quality radial tires of any brand. When rotated, you weren't supposed to change the direction of rotation that the belt originally turned when put on the car.

Now, the current radials seemingly are not nearly as crtical to live with as the earlier versions. Even the older "X" style rotation is acceptable again. Whether it's due to higher quality manufacturing techniques or what, living with modern radials is no worse than the older bias ply or bias-belted tires. Keeping the inflation pressure above the 30psi mark on cars is also something that I'd also advocate, just as with the earlier bias ply and bias-belteds.

I also concur, Willie, with your remark to not use radials as a band aid fix for a suspension that needs to be freshened or rebuilt.

Enjoy!

NTX5467

[Jyrki]

Just one more thing. If you change your bias-ply tires to radial tires on your manual steering car, will that increase of decrease turning effort, or affect at all?

[Guest Skyking]

I just replaced the tires on my 62 Invicta. I had bought a set of Michelins in 97. They road very hard and where quite expensive. I just replaced them with a set of Demension IV's. Both brands being radials. The Demensions ride and handle like the car should, far better than the Michelins ever did. And they were half the price..........plus the whitewall is the correct size.

[Guest]

Many years ago,we had a conplaint on a 51 Special(unstable) We put the tires AND wheels from his 49 trade-in on his brand-new 51 Special,and that cured the complaint.Buick had gone to a narrower rim on lower series car that year.The then-new narrower rims were painted grey on the inside,(probably for identification at the assembly plant)the wider wre black on the inside.I traveled some with a tire branch manager,and he put older Buick 6.5 inch wide rims on his road car. His theory was the wider the rim the better !

[Guest brh]

Jyki,

If its noticeable at all radias will increase your effort required to turn. They have more traction than bias.

[our51super]

I wanted to add that Diamondback Classic Tires (see link in previous post) will work with any brand tire (major manufacturers). We like Michelins so in effect one could buy four tires of your choice and send them to Diamondback and for about $80 per tire, they will add on the white wall.

Happy Thanksgiving!