The Stovebolt Site Forums The Shop Area General Truck Talk Another radial vs bias wheel thread.

Below is a verbatum copy of a letter in the December 6 issue of Old Cars Weekly magazine. I don't know the author or if his claims of being an "expert" are valid but it's info we need when we decide whether to run radial tires on original rims or not. He starts out by referring to a letter publised earlier.

"Bob Brooks' letter citing Sears selling radial tires raises deadly issues. As an accident investigator and an expert court winess on this issue, I remain extrememly concerned that the right information is getting to hobbyists. Rims for bias-ply tires, radial tires and disc brakes are made out of different alloys. Rims for bias-ply tires cannot use radials, and bias- and simply radial-ply rims cannot be used for disc brakes. The forces exerted by bial-ply versus radial-ply (as well disc brakes) are different and need rims made for them. Otherwise, there is over-flexing leading to rim metal fatique and breakage (commonly rim bead edge separation) with deadly results. The rim separations generally give no warning and are almost always catastrophic at speed. One can tell bias-ply, radial-ply and disc brake rims by their marking. An easier way is to make sure the rims come from a car year (1965 and newer) where radial tires were stardard or optional equipment. Disc brake-rated rims can run any tire. Many will disagree, touting their successful usage, some even offering advice with little knowledge of physics and metal fatique. But as a fatal accident investigator and veteran of 62 court cases on this issue, I'm warning everybody: Old bias-ply rims simply cannot continue to take radial tire sidewall forces. The Coker Tire Co. vintage tire catalog commendably gives much the same warning. There is help for Mr. Brooks and everyone else wanting to use radil tires on pre-1965 cars. The Hollander and Mitchell interchange manuals, used by practically every salvage yard, show rims with the same bolt pattern. Just check to make sure everything clears or check out any hot rod magazine for modern, safe rims. If you cannot find the right rims, please continue to use bias-ply tires."
Sam Egan, via e-mail

This makes little sense to me. Force is force, acceleration is acceleration, torque is torque.

While I am sure there are some issues with older rims being used with newer tires, these issues are not adequately explained in this persons letter. They dropped lots of names, and quoted themselves as being an expert, but they did not give one bit of scientific explanation of why this is an issue. Maybe what is actually happening is that people are driving old trucks like they are new trucks, and the old trucks can't take it? How many 70 year olds can run like a 16 year old boy?

I used my old rims (8R19.5) that had tubeless, bias ply tires on them, and installed radial tires on them. These rims are at least from 1958. If I have a major malfunction, that doesn't kill me, I'll let the rest of you know.

When disk brakes were optional, do you think the factory use different wheels for each option? It all comes down to how you use them, maybe the writer of the letter could describe a few of the Fatal accidents and let us decide weather or not it was a wheel issue. Joe

never heard of such foolishness, even back in the day when radials were the 'new wave' nobody talked of "different alloys" for different tire types - considering Michelin has been making radial tires since 1948, maybe we should just use rims from old European trucks

I'd say someone at Old Cars Weekly should call this guy on his 'eggspurt' court cases, there seems to be conflicting views .... and these folks would have the definitive answer, or maybe the Stockton Wheel folks

the primary problem with radials on older rims is a dimensional issue, most use modern car tires designed for wider rims than pre-60s were, and some tire makers will specify rim dimensions acceptable for various tire sizes

Bill

I find it hard to believe that rims that bolt to a disc brake hub vs. a rim that bolts to a drum brake makes any difference as far as rim strength.
I can understand if the tires are slightly different in size, but what difference can it make to the rim when the contact points of the rim to the hub (disc or drum) are the same?
I'm sure that rims are stronger as time goes on, but I need more information for me to swallow that morsel.

In the early days of radial tires, one of the car manufacturers, I don't remember which one, described the difference between bias-ply and radial-ply rims as having a different radius at the base of the bead seat. I don't remember which rim has a larger radius at that location, but a bias-ply rim allows more flexing at the bead when used with a radial tire, so the idea of metal fatigue makes sense in that case. I have seen a few cracked rims in the past, but at the time I didn't associate those with radial tires, and I couldn't say at this time if those wheels even had radial tires. But cracked rims at the base of the bead seat were a fact of life in the past. Beyond that, my experience with radial-ply tires on rims made for bias-ply tires is that full wheel covers need constant tightening and re-setting or they either come off and get lost, or they work around the circumference of the wheel and cut off the valve stem. It seemed to take only a few thousand miles for one or the other of those events to happen.

Harvester

My raw horsepower producing 216 aint gettin fast enough to fatigue anything but me.

I sent the following message to Coker. We'll see what they have to say if anything.

There is a discussion going on about the safety of mounting radial tires on wheels made for bias-ply tires. There is a reference to your company having a warning about the issue in your catalog. I don't see such a warning on your site. Do you have such a warning in your catalog? Any information you can provide on the subject will help. Thank you.

I haven't heard from the Coker folks yet but I when down to the local hotrod shop & took a look at their Coker catalog. It seems this guy is correct in that respect anyway. On page 5 of the Coker 2006 catalog they say "Rims designed and manufactured years ago for bias ply tires used on vehicles without radial tuned suspensions now using radials can cause cracks in old rims." Gramarically it doesn't read well but it's an exact quote.

Also Bill, the newsweek story you link to doesn't address the wheel cracking issue, basicaly ride and tube vs tubeless. The second link is only some organization's main page. Where on it do you want me to look?

im gunna make my old 49 a daily driver and switchin to radials,just in case thier is a problom i think im going to go with new rims as well,what rims would you guys reccommend,and what rims will fit ok with the ol 49 1/2ton truck

Tiny - the organization linked is the Tire and Rim Association, the group that sets the standards that the US govt refers to in setting it's rules ... having checked the govt regs, no mention is made of rim type other than reference to the "dimensions", and every other discussion I've seen refers to the width of the rim being appropriate for the tire size

note here where the TRA standards are discussed, there's no mention of alloys or age of rims, but a lot about width and aspect ratio

the TRA charges $80 for the full book on the subject, but according to the reg you should be able to see a list of "approved" rims at any tire dealer!!!

find the relevent following govt requirements here
"S4. Tire and rim matching information.
S4.1. Each manufacturer of tires must ensure that a listing of the rims that may be used with each tire that it produces is provided to the public in accordance with S4.1.1 and S4.1.2.
S4.1.1 Each rim listing for a tire must include dimensional specifications and a diagram of the rim and must be in one of the
following forms:
(a) Listed by manufacturer name or brand name in a document furnished to dealers of the manufacturer's tires, to any person upon request, and in duplicate to: Docket Section, National Highway Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 20590; [.....] "

no the the Business Week discussion doesn't address cracking, but it seems to discredit it when it states:
"MYTH AND FACT. The supposed hazards of using radial tires on vehicles that were originally equipped with bias-ply tires are some of the hardest myths to dispel, partly because, as in most myths, some truths can be found. For instance, it's true that many older vehicles were not engineered to take advantage of radial tire designs. But that does not make using radial tires on older vehicles unsafe or a waste of money.
When combing through the myths to get to the facts, four areas emerge. Three deal with physical characteristics: tire size, contact area, and tire weight. The fourth deals with load-carrying capabilities, and is the concern of least importance."

how about if the cracking isn't a result of the tire type, but because of an inappropriate size? or even just metal fatigue due to age and abuse?

and I noted that Coker seems to think using radials is a cosmetic question

I've been using radials since the 70s and have never had a vehicle newer than 67 - I've worn out sets of radials on old rims, city and highway driving - never had a rim crack

Bill

In January of 1968 I made a deal to swap my '65 Cadillac Convertible de Ville on a '68 Chrysler 300 Convertible. I wanted all the performance I could get but I also wanted the best looking car I could get. Agonized for days whether to get a red car with a tan top or a white car with a dark olive green top. Finally chose the white with green combo. Wheel choices were a standard 14" wheel, a styled, chrome 14" wheel, or a 15" wheel with disk brakes. Wanted the chrome wheels badly so ordered them with heavy-duty drum brakes. Ordered the 440 engine, the most powerful engine available in a Chrysler.

Got the car and tire wear was pitiful; partly because I drove very fast through turns and partly because no one seemed able to set the torsion bar suspension up correctly. 5,000 miles to a set of tires was about normal, 6,000 was extra good. As you can imagine I was far from pleased. Finally bought Michelin radials from Sears. Of course they were mounted on the wheels I had. Tire mileage increased to about 14,000-15,000 miles. I continued to run the car very hard. Not only did the tire wear improve but handling became immensely better. I ran the car that way for 4-years with no wheel problems. Traded it to my brother and he drove it maybe two years more. Were my original wheels manufactured for radial tires? I doubt it because I don't think Chrysler even offered radials as an option then. Would I do it again? Absolutely! Was there any danger involved? I have no way of knowing.

working many years in mobile equipment, we had a variety of rims crack under use. Most were due to a manufacturing flaw acknowledged by the manufacturer.

I have split and cracked wheels / rims when auto crossing. This is a problem along with chording tires and losing ball joints. I have not come across any cracked rims in some time on a non-race situation. I have seen wheels crack by improper torque of the lug nuts (people using impact wrenches). I have seen wheels crack around the bead on a really old set of wheels, however the material was thin and corroded. I have seen split rims let loose. Could this be a root cause?

I believe that this Sam Egan person to have his facts confused. Also, if he truly is a veteran of "62 court cases", wouldn't we find evidence of this on the internet? I have found a writer, surfer and producer. Then again, I get a speeding ticket, and you can find my name, address, car make, model, license plate and issuing officers name.

Just my $0.02

Scott

Sam Egan, general manager, Automotive Information Clearinghouse, La Mesa, Calif

ya didn't look far enuff Scott seems to be a business that sells "automotive manuals" but doesn't have a web presence

Bill

This is probably not exactly related to this thread but I thought I would add my experience. I have a stock 49 half ton with 4" wide rims. When my Cooper 650-16 needed replacing I bought a set of 215-85R16 Uniroyals. When I got the truck to the tire dealer he did not want to install them on the narrow rims. His spec book needed a 6.5" rim width and he also said my rims did not have a safety bead.
This whole story is covered quite extensively in another post many months ago so I won't dwell on it here. Rather than trying to find a correct set of rims, ones which would also take my stock hub caps, I decided to buy Firestone 650-16 bias-ply tires. I have had them on now for over 6 months and I love them. Yes they sometimes track funny if you get in a rut but they are smooth running. Even when sitting for a few days they do not have that cold tire thump. I also like the way they look versus radials.
I do not drive freeways or often above 40 mph and I do about 2000 miles a year. Steering is lighter than radials (I had 15" radials on my 53 so I can compare). I am not saying they are better than radials, merely that I was very pleasantly surprised by everything with them and would not hesitate to use that type of tire on any old vehicle I owned.

Isn't it cool when there is a discussion & disagreement without people calling each other names. Maybe we should arrange to get Mr. Welch & Mr. Egan together to discuss the issue.

Personally I feel the warning against running radials on pre 65 rims has some merit. If there weren't cases of wheel failure Coker wouldn't put the warning in their catalog. Add to that the anicdotal experiences of other drivers who've experienced wheel failure and there is a good case that it does happen, albeit infrequently. Obviously there are those here who have run radials without wheel failure and I hope that continues. I don't want to wish bad luck on anyone. It does, and should, provide food for thought.

One last post from me on the subject. I just got a reply from Coker to my querry. It's posted below verbatum:

Vehicles designed for bias ply tires may drive considerable different with radial tires. Older wheels that were designed for bias ply tires may crack if used with modern radials. Use caution by inspecting your wheels on a regular basis. Radial tires exert more force on the wheels than bias ply tires and can cause them to flex. The flexing can lead to metal fatigue, cracks and breakage. However, the most common effect of the rim flexing we see is the wheel cover sliding on the rim or popping off. We suggest a detailed inspection of your rims and that you replace any suspect rims with modern reproductions if you plan on using radial tires.

Sincerely,

Jess Hoodenpyle





Jess Hoodenpyle

Customer Service Manager

Coker Tire Co.

1-800-251-6336

All the above postings contain good advice and links to good information.

My radials are Cooper LT215/85R16 that are supposed to fit a 5.5 (and a little larger) rim. My rims are 4.5, so I have been careful to inspect the wheels regularly.

The 215-85 is a relatively tall and narrow tire and this puts less stress on the rims than do wider/lower radials. It should also be noted that LT-designated tires are supposedly higher "ply rated" than passenger style tires

My high speed is about 65 mph (3.55 rear end) and speeds above 50 mph would only be on an Interstate Highway (lower speed turning, most of the time). My trucks never run fully loaded. Better safe and pre-warned than sorry.

Tim

Well, here we go in that same old circle again.

I just replaced my Michelin radials that I bought gently used and put 40k on them with a brand new set of Michelin 215 85R 16 LTX model. I have been running 50 psi but will run these at 45 psi for the winter. I am a daily driver year round and have logged several long distance trips at 70 mph. I drive safely, do not fool with the rice rocket children, have no radio and stop at the next rest stop to handle calls. Your results may vary.

What follows was lifted from the Didiamondback tire site - dbtires.com

Wives tale or fact…
Are radial tires safe for my stock rims?

It is a common question for us to offer proof that Diamond Back Classic radials can be installed tubeless on older rims. I do not know how I can offer physical proof, however, I can offer an opinion based on my 35 years of experience.
The issue that needs to be discussed- can a radial tire be installed tubeless on an older rim, and will radial tires cause older rims to split? Let's look at our answers to these two questions.
The first radials were imported to the US in the late 1960's by Sears. These tires were manufactured by Michelin. Because of the improvement in ride, handling and safety these radials became immensely popular. These tires were sold by the hundreds of thousands by Sears nationwide. Neither Sears or Michelin ever specified that these tires had to be mounted on different rims—these tires were sold in numerous sizes for every make of American car and most were mounted tubeless.
The first American company to build radial tires was BF Goodrich in the late 1960's. BF Goodrich spent millions on the development and advertising of modern radial tires. Again, BF Goodrich never said that radial tires had to be mounted on specialized rims. Radial tires were installed on the stock, OE, rims. Were there any problems? Not to my knowledge.
Let's step back a few years to 1957. This was the first year of the tubeless tires developed and manufactured by BF Goodrich. These tires were built to work on existing rims. There were no rim modifications to accept their new tires.
The point to be made is: throughout the development of the tubeless tire and the radial tire, there was no parallel development in rim technology.
In my years in the tire industry, I have not seen a tubeless radial tire that has caused an original rim to split or malfunction.

Bill Chapman
President CEO

Tubeless tires were standard equipment on '55 Fords and Chevrolets and on '56 Dodges and Plymouths. Also on 1956 light-duty Ford trucks. This can be verified in "Standard Catalog of American Cars, 1946-1975" and in "Standard Catalog of American Light Duty Trucks." A former neighbor of mine purchased a new 1956 Ford F-600 (2-Ton rated) log truck and it came with tubeless tires. I remember people were concerned about having them on cars because they thought they might not hold air and Ford put them on trucks.