They Don’t Make Tires Like They Used To: The Forgotten World Of Bias Ply
I’m writing this article to talk about tires for the trailer queen. The owner that wants tires that can sit in a garage for decades without being driven. This is not about daily driving or road handling ratings.
It’s common today, even government law in some areas to recommend that you replace your tires every three or four years when they lose their tread. What if I told you this is a modern phenomena?
Beginnings Of Tire History:
The rubber tire was first used practically by John Body Dunlop and made for the first bicycles. Hence the name Dunlop tires we used to hear. Prior to this we used wooden wheels.
It wasn’t brought over to American on cars though until the year 1911 when Alexander Strauss invented the inner tube tire. For the first time a rubber tire was able to support the weight of a vehicle. This my friends would become known as the Bias Ply Tire, and we used bias ply tires for the first 60 years of automobiles. This was back when you had to know how to change a tire, because bias ply tires are more prone to going flat while you’re driving. This wasn’t a big deal for anyone.
Bias ply tires used organic rubber and nylon technology. Nylon cords were wrapped at a 30–38 degree angle providing structure for the tire. These tires were made with nothing but organic rubber and nylon fibers, and a host of chemical compounds that would probably be illegal today including asbestos but worked well on the road.
What if I told these tires had an indefinite longevity? What do I mean by longevity? I don’t mean tread performance or tread wear. In fact radials handle much better in terms of performance by itself and last much longer on the road I will explain down further in the article. By longevity I am referring to the tire’s ability to maintain its original structure.
Want some photos? Want some proof? Here are classic car owners who proudly wrote in to me for this story from across the country.
“I am still on the original 1940 tires on our museums Seagrave Fire Truck. They have 6300 miles on them. Looking for donation to buy new ones and looking for a spare rim for a spare tire.” — Ken Evans (Sunset, AZ)
“1970 Bias plys I bought when they were new. I still have the receipt. But not driven much or over 45mph” — Tim Hoffman (Los Angeles, CA)
“These bias plys were on the car when I bought it in ’98. Still going strong today. No plans on replacing them.” — Diz Dean (Youngstown, OH)
“Original tires on my 66' with 18K original miles.” — Jim McCarthy (Brighton, MI)
“This 1959 had 13K original miles and all 6 original date coded tires on it. I had to replaced the fronts a few years ago as they started chunking apart.” — Wayne Trent (Hudson, FL)
It was once not uncommon to see trucks, tractors, and yes cars keep their tires for thirty or forty years. We simply drove less than we do today. Tires received less wear, but bottom dollar is they maintained their integrity.
More proof? Look at this YouTube video where Jay Leno drives a Volga with original USSR tires on them from 1966. Jay Leno keeps a lot of original tires on his collection. Modern tires would not have held up that long. Now let me explain why bias ply tires actually provided superior performance.
The thing about bias ply technology is that today there are almost no tire shops that know how to handle them. In order to get the best performance out of a bias ply tire they have to be controlled. Most car owners back in those times did not eve bother doing this and it shows.
It was calling tire shaping or tire truing, and this was back when it was considered a high skillset. Tire technicians were the doctors of the automobile industry, and you can think of that scene from Mad Mad Mad World. See those white round tubes in the background? That is what used to go inside of a tire. I always think of that scene. There used to be service shops suits and all that would trim your tires and tune your carb as they refilled your gas tank.
You see one of the downsides of bias ply is that they touch the road less often if not maintained. The tire is all one unit, sidewall flex is transferred to the tread. However it was possible to get even wear out of bias ply tires. Just ask my friends over at K&T Vintage Sports Cars in Bethlehem Pennsylvania, and no I am not getting paid to plug them. They truly do great work and are one of the few “real” tire shops left in the country.
“One of the problems with the modern tire shop unless they deal with bias ply wire wheels, they align tires on an untrue surface. They only use counterweights.” — Ken Beck
I’ll get to modern tires below, but you can see that a bias ply tire does not have to wear unevenly. Uneven tread is not why the industry switched to radial tires. A true surface is much more important than tread wear.
Modern Tire Age:
Sometime in the mid 1970’s belted tires started taking over. That was belted bias ply and radials. The first actual use of a belted tire was actually by Goodyear in 1967 and it wasn’t bad at first. The first belted tires were bias ply tires that used fiberglass belts instead of steel at a 90 degree angle. Trademarked as the Polyglas Tire and these in my opinion were the absolute best of both worlds. It provided a means of avoiding the common occurrence of flat tires and superior traction control with the road.
However Americans started wanting even more strength and became lazier you could say. The average teenager was no longer expected to learn how to change a tire on the side of the road or make roadside patches, and tire shops wanted an easier and cheaper way to service tires. The old tire shop was a thing of the past and lifetime tires would now dissapere.
So in the consumers’s quest for a stronger tire we switched to steel. Steel reinforced tires. Introducing the Radial Tire that blew up in the mid 70’s. Radial tires are made with steel chords running at a 90 degree angle. Purely steel, with a much thinner layer of rubber surrounding it. It gave much improved traction control without the need for truing, and strength to prevent flats. We now use weights on our tires with less tread wear. The industry gave itself a high five, and consumers were never happier or so they thought. Starting the drum beats.
Did we trade convenience for longevity? Again I have to point out that my reference to longevity means an object’s ability to maintain its original structure. To understand why modern tires are inferior for longevity we can use a bridge or highway as an example. Or even concrete building. Reinforced concrete is made by running steel rebars through the concrete. This gives a reinforced structure that is stronger at the surface. It can handle more weight and vibration, but the problem shows up when it ages down the road. We often forget about this.
The concrete will literally rust from the inside out, because the steel rebars will corrode over time as moisture gets inside. Steel bars will corrode, and it will lead to buildings and roads cracking because of a cancer below the surface. That is exactly what happens with modern tires. However we can’t even call it rubber anymore its silicone, and silicone the industry uses today and it’s great at absorbing moisture. So when you drive tires down the road, moisture reaches the steel in the tire and it begins to rust from the inside out the second you drive it off the lot. It will even corrode just in storage.
Pretty soon within four or five years a radial tire will experience two phenomenons. Sidewall Cracking and Separation. On radials the steel bars are your only layer of support. The rubber is a lot less firm than on a bias ply tire. Once your steel structure falls apart the tire itself implodes. If you’re lucky it will show sidewall cracking first. Other times it simply explodes when it gives way. You usually run into exploding tires on museum cars because the rubber never sees rain. It’s never driven so it shows no visible signs of corrosion. However inside is a different story.
To appease classic car enthusiasts the industry started developing steel belted bias ply tires, but those too suffer from the same problems. However they are a little better because you have a nylon structure that is also support the tire. It does not solely rely on steel. That is why many classic car enthusiasts endorse buying conventional bias ply tires over radials. If your car is going to sit in a garage for most of its future life, your radials are not going to stand the test of time. Bias ply tires can outlast the life of the car. It’s really not uncommon to keep bias ply tires for many decades if not more. Remember we’re not talking about treadwear here. Radial tires have longer treadwear. We’re talking about longevity of the original structure.
I like to compare the two tire technologies to single stage and clear coat paint. Clear coat paint is more durable to the outside world but will eventually crack and fail after less than a decade. Single stage paint will outlast the life of the car for a century, but will fade with age if not maintained. The same can be said about old fashioned tires.
It’s also the source of the rubber. In large part we switched to cheaper synthetic rubber. When your source is cheap it is more prone to dry rotting. A good example is weather seals. I know this because I spent $1400 on rubber seals for my classic Mercedes. Mercedes brand sources rubber from Germany that will last the lifetime of the car. You can buy aftermarket weather seals made in Croatia that will last five years they crack.
American tires are simply not manufactured in America anymore. Michelin, Pirelli, Continental, Bridgestone, Yokohama, Goodyear, and Cooper all have plants in Mexico and China. Goodyear and Cooper are the only two American companies left in the tire business. However you can still buy American made tires from all seven companies. There is an art to buying good quality tires. It still can be done but it’s tricky.
You have to walk into a tire shop and before you go to buy your tires, you have to demand to see the plant codes stamped onto the rubber. It’s called a DOT code, and you can read about the tricks to transcoding it below.
Even if some tires are assembled in America, does that mean they were manufactured in America? Where is the rubber sourced? Where are the raw materials sourced? Are Americans growing rubber trees in their backyard?
My Take / Opinion:
Tire manufactures will now tell you that tires are meant to dry rot. That tires naturally will dry rot and crack after less than three years. Nonsense. This is the reason we no longer sell white walls anymore. You see that used to be a selling point on cars. You would commonly see ads that stated, “comes with the original tires”. That used to be a wanted option from used car dealerships and ads in the white pages of the local newspaper.
One company that is prone to dry rotting from the inside is believe it or not, Michelin. I have heard more horror stories from Michelin owners complaining about letting their tires sit for two years on their restoration, and then going to drive it only to find out the rubber is cracked.
So yes the radial technology we use in tires today makes it better for daily driving and easier maintenance for technicians, but tire manufactures have switched to cheaper synthetic materials that do not hold up sitting in somebody’s garage as a collector.
“A BFG engineer once told me if they still made their tires out of the compounds that used to be used they would not be affordable to anyone driving on the road today.” — Jon Davis (Hesperia, CA)
I truly believe that. We have made one trade off for another. A tire could be manufactured with very thick high quality rubber that would hold up sitting in a garage for decades without steel. Why not make tires with stainless steel? Cost may be the obvious first reason. Why can Mercedes rubber weather seals last fifty years, but rubber on a tire will crack in less than four? I really don’t buy that argument, and the proof is in the pudding in regards to why this happens. That is corrosion from an inferior design.
As a classic car collector, I would always consider buying a tire that may not last as long tread wise, but does not to dry rot. I only use regular bias ply tires on all my cars. Airplanes are a good example. Jet airline tires are made to withstand 300 ton falling onto the ground for landing, also bias ply.
”The tires I put on my light weight plane decades ago are fairly thick and heavy, but they’re meant to go on trainers and take a beating. I’ve never seen one wear down to the cords even though I do beat them up sometimes.” — Anonymous Flight Instructor
So that’s the final point I conclude with. Tires only last two or three years today before self destructing because that is what they are designed to do. Modern tires are engineered to provide a mode of transportation on modern vehicles with drivers who don’t know how to change a flat tire, at an economical price we can all afford. Tires don’t have to be made this way, and I hope the next generation of car enthusiasts continue to keep bias ply tires alive and tire truing alive for future classic car collectors.