The tires on my new to me 26 coupe are really nice looking made in New Zealand 21' 4.5-4.75. Tread wear is practically none. HOWEVER, they do have some very minor cracking in the sidewalls, not a lot of it and not at all pronounced. Is there any way I can help to soften up/revitalize the tires some? It would be a shame to toss these when they're barely used.
I have been running tires with slight cracking on the sidewalls for years with no issues. I am not a speed demon and rarely go over 30 mph. I am sure others will disagree but it has worked for me.
No way to restore tires that I know of. If sidewalls are cracked they need to go. Tire properties degrade with age. Normally 5 years is considered the life expectancy of performance tires (fast car/motorcycle) as the rubber composition degrades to the point that available traction is reduced. You could do what Bert Monroe did to qualify at Bonneville Salt Flats (rub on black shoe polish) but I wouldn't advise that.
In the motor home world, tires are recommended to be replaced every 7 years. These are very expensive tires that usually have almost new tread left on them. Our cars are not as heavy as a motor home but as a rule I have found that the clincher tires are not as well made as the motor home tires.
If they were mine I would replace them just for safety. Cracking can show a weakness in the sidewall.
If nothing else, be sure you have a good spare with you.
As long as you go slow - I'm with Val on this.
I too agree with Val. A light car at low speeds can get a lot more out of a set of tires than a heavy car at high speeds. However, if you plan to drive it regularly at much over 35 MPH then perhaps you should replace them.
I purchased a rolling chassis just because the tires and wheels looked great for my War Wagon. The tires still had nibs on them, but were turning brown with age and few minor cracks.
I had a product that I purchased for dressing up a spare combat tire on my WWII jeep that would never get run on. It is a tire black paint that is water based. It's pretty thick out of the bottle and you can cut it with water for a light top coat. Out of the bottle, it will fill cmall cracks and lasts a full season at least.
I looked for it in tire and auto parts stores because I remember tire dressing in the 7o's, but could only find it on line.
Won't soften rubber or make old tires new, but will make them look like new.
I'd run them too. My understanding is that when they are cracked, the cord will be exposed to the elements and can rot if it stays damp, but if it's parked indoors.....
The tractor guys like this stuff. Antique tractors go real slow and the rear tires for tractors are very expensive.
My first set of new tires started to accumulate minor cracks within a year. 10 years later, with modest miles on them, they are slightly worse at 10 years old than at 1 year old. Every tire I've worn out from touring was new during my ownership, cracked early on and ran fine until they wore out. My main touring car is a 1919 roadster and I cannot, repeat, cannot wear out the ca. 1968 Wards Riversides. My guess is that they are harder on the pavement than the pavement is on them. They exhibit cracks, as well. Probably first showed up in 1969...who knows?
If the cracks are cracks and not spread open at all and are not in the tread, but side walls, I'm with Val and others... I'd keep the speeds to 30 MPH and forget about it.
The most important question regarding this issue, is what are the casing cord fibers made of?
I have nylon cord tires that are about fifty years old that I wouldn't hesitate to put on a car and drive across the country with. Be advised, that tires that old will have a slightly reduced coefficient of friction which in turn does slightly reduce the braking ability.
For nylon (and most other synthetic) cord tires. In every other sense, tires for antique automobiles made more than twenty years ago, are better made, and used better materials, than anything you can get new today in the same size. If they are not stronger and safer than the new tire is today? Give them about five years. The old tire should not be much different in five years than it is today. The new tire today in five years may be half way to failure just sitting in the garage (judging from some I have seen).
HOWEVER! If the old tire is cotton cord (and some antique auto replacement tires did use cotton cord well into the 1970s)? Everything changes. Cotton rots and disintegrates due to water and microbiological infection. Microscopic cracking can allow water to invade the rubber casing surface. Microbiological infestation can result from spores left in the cotton from before the tire was made, or carried in with the water. Either way, the microbes eat at the cotton fibers, taking away most of its strength.
Unfortunately, there is not a lot that can be done to test an old cotton cord tire to determine how strong or weak it is. Like our Babbitt thrust washers, as they age, they become more and more likely to have degraded beyond any probable safety.
Other than a static display (wall hanger), I would not trust any cotton cord tire to be driven on.
Nylon cord, gotta be pretty bad before I wouldn't use it.
Mathew, Just FYI, they stopped making tires of that size here in New Zealand in the late 1960s. There was still stock about to be bought into the 1970s but yours would have been made at least 47/48/49 years ago and possibly longer.
I've got 40 year old 20x5:00 New Zealand Olympic tires on my speedster and they have tiny checkmarks in the sidewalls that do not concern me in the least. On a modern vehicle driven at highway speeds it may be a reason for concern, but on an antique- run em!
It seems like the new tires crack fast. I bought a front tire about 7 years ago and within 4 it started cracking. I've got 2 I bought in the middle 90s that aren't cracked as bad and one rear tire that's probably 50 years old and it looks as good as either of the other 3. I just drive, but 30 is about as fast as I go, but I don't drive enough to wear them out faster than they crack and don't have enough money to buy more every few years. Then again, I don't replace tires on my modern car that goes 70 until 2 layers of wire are showing through or it just won't hold air.
Worlds Fastest Indian used shoe polish to remove tire sidewall cracks. Just sayin.
Thanks for all the responses guys. It sounds like I'm going to try and use them. I'll keep an eye on them as I do. I thought they'd probably be OK since my grandfather is running 50+ year old Ward's Riversides 30X3 1/2 on his roadster and has had no issues with them either despite years of use and minor cracking as well.
Unfortunately, they don't make tires like they used to. I purchased a set of four 21" Universal tires from Mark Auto in 1971 for my '26 coupe and 46 years later, all four are still on the car. I periodically rub them down with brake fluid. Jim Patrick
??? Jim, The old Dot 2,3,4 brake fluids are vegetable oil mixed with alcohol. That is to keep petroleum away from the seals & raise flash point but also why it is hydrophilic (takes water in from the atmosphere).