The Stovebolt Site Forums The Shop Area General Truck Talk HELP WITH BUYING RADIAL TIRES 1949 3600

Running Goodyear Bias Ply 7.00 15 whats a Good Match In a Radial I Like Michelin Tires but Open for Suggestions?
Thanks!
Mike 609-698-8706

You can google "tire size converter" and look for a diameter matching. Then, what I did was buy a used tire and mount it on the front and check for fit at the tie-rod ends.

It might be wise to get rims made for radials as the forces of radials are different....some say mounting radials to bias-made rims may cause failure.

I have bought Cragar Smoothie 15 inch rims and mounted 235-75-15 tires....Firestone 380 whitewalls, currently buy 3, get 4...they are about $74 each. My speedo is off by 4MPH at 50 now, but I intend to replace the rear gear later.

A friend is running 215-85-16's on his 1953....probably on the old rims.

Thanks for the Input!
Yes Ive Heard the Stories On Rim Failure but think that happens not all too often.
I plan on Installing Michelins 235/75 R15 with Flaps and Radial Tubes cant Find Radial Rims that enable the Use of the Original "DOG DISH CAP",Put Old Tire Back On Truck and See the Clearance Issue of the Tie Rod Ends will be No Issue as the Sidewall Bulge is well below the Tie Rod End and should be of no concern.
We Shall See Wednesday They are being Changed.

Radials or bias ply tires for your classic?

Some purists think they want bias ply tyres on their classic car because they look like the original style tyres. Just hold on. Unless you don’t intend to drive the car (except maybe to an occassional show near home), you should be driving on radials. Why? Because they’re much safer. Let’s face it, you’ve got a lot rolling on those tyres. I’m not just talking about your investment, but the safety of you and your family. Radial tyres respond much better in an emergency, and that’s critical with all the cars on the road today. In fact, radials just may save your life. In a quick maneuver, the tyre tread stays in full contact with the road because of the tyre’s construction, giving you maximum control. The radial’s sidewalls can flex, which is what keeps the rubber in contact with the road surface. Bias plies can’t do that, so they inherently handle poorly, and in an emergency, you can easily lose control of the car. Here’s a list of advantages over bias ply tyres.You can decide for yourself if they belong on your car.• Faster response and better control• Easier steering effort• Smoother ride• Less road shock is felt• Less wandering, straighter tracking • Much better puncture resistance• Less rolling resistance, better MPG• Better emergency braking • Better traction on wet roads• Longer tread life As you can see, radial tires are a smart decision. Anything else doesn’t make sense. The use of tubes. Never run tubes. That’s like stepping back 40 years in technology. If you still insist on bias ply tyres, just make sure they’re tubeless. The chance of a tube failing is much greater than a tubeless tyre failure. Why? Tubes create heat and friction, and don’t dissipate heatwell...and a tyre’s worst enemy is heat. Also, over time, tubes “grow” and become too large, and they actually develop creases — and then they split. If a tube is punctured or fails, air loss is immediate, giving you little or no time at all to react. They’re dangerous.Often, a tubeless tyre can be driven for a while with a puncture. My advice is to take all tubes to the swimming pool where they belong. Now, there’s one case where you may have absolutely no choice, and that’s with wirewheels, because the inner spokes protrude into the rim. In most cases, there’s a rubber liner covering the spoke ends. Some manufacturers offer tubeless wire wheels, and my advice is to try to get those. If you have to run tubes, just be sure the spoke ends are covered. Remember that if (and when) your tube is punctured by a spoke end, the loss of air is going to be immediate and without warning. Hang on. What about mixing bias ply tires with radials? My first question is, “Why would you want to?” But yes, you can drive the car down the road, but remember...in the event that you must execute a serious emergency maneuver,you can easily lose control of the car and the results could be disastrous. The two different tyres have vastly different handling characterisics, and a loss of adhesion in either the front or rear could mean loss of control. The difference in the performance characteristics of the two types of tyres is enormous. So this is an unsafe practice.

No one has ever identified or explained how a radial tire can actually cause additional stress on a rim. I’ve read and listened to opinions and that’s all they are is opinions unsupported by scientific testing data. I believe this myth is backwards. I believe radials cause less stress on rims than the old rigid bias ply tires.

The Department of Transportation has created the new FMVSS 139 (Tread Act)* for the purpose of “establishing new and more stringent tire performance requirements that apply to all new tires for use on light vehicles.” Here is the DOT’s assessment of the differences in performance characteristics between bias and radial tires.“A bias passenger car tire carcass is typically made up of two or four plies of cord material that run from bead to bead at an angle of approximately 35 degrees to the centerline of the tire. This type of construction provides a very strong, durable carcass for the tire. Because the ply cords criss-cross and all the cords are anchored to the beads, the carcass is stiff and relatively inflexible. This type of construction prevents the different parts of the tire from acting independently of another when forces are applied to the tire. As a result, a bias construction is susceptible to impact breaks because it does not easily absorb road irregularities.” This causes more rim stress.

“By comparison, a radial passenger tire carcass is typically made up of one of more plies of cord material that run from bead at an angle of approximately 90 degrees to centerline of the tire. Because the cords do not criss-cross and because the opposite ends of each cord are anchored to the beads at points that are directly opposite each other, the radial tire carcass is flexible. The radial tire is reinforced and stabilized by a belt that runs circumferentially around the tire under the tread. This construction allows the sidewalls to act independently of the belt and the tread area when forces are applied to the tire. The “independent” action is what allows the sidewalls to readily absorb road irregularities without overstressing the cords. This ‘independent’ action allows two important things to happen (1) the tread of a radial tire remains fully in contact with the road over the entire tread width, and (2) the ply cords and sidewall are able to absorb forces without exerting the twisting force on the beads that are exerted by bias construction.”

Because a radial tire is so flexible, it must have some type of lower sidewall support. Remember the upper third of a radial’s sidewall does all the work. The lower two thirds of the sidewall is supported by the portion of the tire called the Apex. The Apex consists of two stiff, triangular shaped pieces of rubber that extend upward from the bead where the tire sits on the rim. The apex is thickest at the bottom and tapers upwards to a small point. The sole purpose at the apex is stability and support. The apex is a very strong, rigid piece of rubber – so rigid that it becomes the principal component of the run flat tire. How does the apex relate to rim stress? Simple - it transfers road force up to the flex area so that the flexible upper sidewall can do its job of absorbing road forces without “exerting the twisting force on the beads that are exerted by bias constructions.”

Don’t forget about inflation. Radials typically run about 10 psi more than the old bias tires. A poorly inflated radial causes more drag and will create more rim stress. A properly inflated radial with more rigid sidewalls will have less rolling resistance and less
stress on the rim.

The following paragraph is from Old Cars Weekly – 12-6-07 issue. Here’s a condensed version of what someone has written:

“Rims for bias-ply tires and radial tires are made out of different alloys. Rims for bias-ply tires cannot be used on radials. The forces exerted by bias-ply versus radial-ply are different and needs rims made specific for each application. Otherwise there is over flexing leading to rim metal fatigue and breakage. One can tell bias-ply, radial-ply and disc brake rims by their markings.”

I witnessed the transition from bias to radials and I don’t agree with this letter. The letter also says, “ Rims for bias-ply and radial tires are made of different alloys.” Again, I disagree. There were no industry standard markings to identify rims for radial use or rims for bias use, and no alloy changes just to accommodate radial tires.

In summary, all rims are subjected to stress (flex). The stress (flex) point can change its location on the rim (bead seat) depending on many factors – tire size, tire width, inflation, vehicle weight, bias or radial tires. If you have a 50’s or 60’s car, you would be safer with new rims simply because you don’t know the history of the older rims. In the last sentence of the letter someone wrote to Old Cars Weekly he states, “If you cannot find the correct rims you should continue to use bias-ply tires.” This is at best very bad advice, simply because of the safety advantage of radials versus the poor handling characteristics of bias tires. If you are using old rims, you could have a rim failure. The chances are extremely remote, and in my opinion, the cause won’t be whether you’re using radial or bias tires- it’s just an old rim.

I noticed you have a 3600. Do you run an 8-lug rim? If so, have you thought of going to a 16" rim? They are plentiful at the junkyard. They are also now being reproduced and I believe will accept the hubcap you mentioned. I think Classic or Vintage Wheels offers them.

Hey Thanks for the Reply,I will Check www.wheelvintique Offers an 8-Lug Radial Rim however cant Use Stock Caps They Sell a Moon Dish but that just Kills the Original Look of the Truck!
Im Scheduled Wednesday to Have the Bias Plys Removed and the Radials Installed with Flaps and Radial Tubes which should be OK not Ideal but OK willing to deal with Negatives associated with Using Original Rims,Flaps,Tubes.
Thank You!

If you are going to run tubes, the tires MUST be tube type construction. Running tubes in tubless construction tires canlead to prematures tire failure, especially if the truck is loaded and/or running highway speeds. This is due to the chaffing of the tube with the inner layer of rubber in the tires, which causes exsessive heat buildup and rubber degradation. I know there's several guys on here that have done it with no issues, but I, as a tire industry professional, cannot advise doing it.
Another note on tire selction, make sure you get the proper load rating. A P rated tire will not live long on a 3/4 ton truck. You will want at least a C range tire.

Here are the Tyre Specs:
Tubeless
Tyre width : 235 mm
Tyre aspect ratio : 75%
Tyre diameter : 15"
Tyre durability : C
Tyre load index : 104/101
Tyre speed symbol : R 170 km/h
Tyre usage : LT
Tyre season : All season
Michelin X Radial LT
Ideal for pickups, full-size vans, and sport utility vehicles, Michelin® X® Radial LT tires are dual-purpose tires (recreational/commercial) capable of handling all seasons and weather conditions.
- Extra puncture resistance
- Attractive, sporty look
- Dependable, all-season performance
- Long, even wear
Tread-Polyester 2 Ply,Steel-2-Ply,Sidewall-2-Ply Polyester

Why run the tubes, does the rim leak? Ever thought about powder coating the inside of the rims to seal up weep holes? Maybe a rubber-ized coating of some type? We run a few tubes in bus tires when the they get small sidewall holes from wire or small nails and the tread is still deep. It saves trashing a good tire.

Good post on the rim issues, I think this falls in with the harden valve seats. Everyones believes it, but there is no real proof its true!

Joe

One of the best posts I have ever read on my close to ten years here on the board. As a daily driver only vehicle my '49 with radials on stock rims with NO TUBES has performed flawlessly nearing 50 K miles. No flats. My first 40 K miles were on a gently used set of Michelin LTX 235 85R 16's. I liked them so much I bought a brand new pair off the 'net, sent to my house and installed by my locally owned used tire place.

There is a lot of misinformation out there from "tire guys" who have 0 miles and 0 experience running a radial on a stock rim. As I near 50 K on my old truck with several 2k trips @ 70-75 mph I wish you all happy motoring and good luck with your decisions.

The rims in question are the 8 lug 15", which are a multi peice wheel. They are not an airtight design, and must run tubes.

Ok, now I know why all the pieces are needed, I would still go it. We ran tubes in drag slicks for years and I can't think of any tire that flexes more then a slick does.

Joe

That's all well and good, IF the tire is constructed to run tubes. Running tubes in modern tubless construction tires is asking for tire failure. Too much internal friction. Seen them fail with under 100 miles of highway driving.