old wheels with radial tires

[mastertech]

I am needing to replace the tires on my 51 desoto since one blew out on saterday. They were bias tires about 15 years old (wonder why they went bad) The question is and i should really know this answer but have heard diffrent things on this is it safe to put radial tires on old type wheels? I have heard that the older wheels for bias tires wont handle the flex of radial tires and eventually break. I have been working in a chrysler dealership for 30 years anf havent had or heard of any problems. But i do rember a service bullten around 1976-78 NOT to put radial tires on anything but wheels rated for radial tires. Now since the car sits quit a bit and when i do drive it dosent go very far and usually not out on the highway very far i dont thing I will have any problems. any advice would be helpful

thanks Melvin Schwentner

[ted sweet]

my 66 newport has had radials for the past 20+ years.

[Barry Wolk]

My reply is anecdotal, not scientific.

I had to buy new wheels to get rid of the spacers the previous owner had put behind the front wheels to make the wider cross section of a radial tire clear the top ball joint. I ordered custom new wheels from Coker with a 3/4" shallower back set. This pushed the wheels outboard and widened the wheelbase, leaving lots of clearance for the wider tires.

The new wheels weigh 5 lbs more than the OE wheels. This extra weight is in metal thickness. This extra thickness is what stopped me from constantly loosing hubcaps after installing radial tires. The hubcaps no loger make a cacaphony when I pull in the garage. The flex was eliminated by thicker metal. All I see is cause and effect.

Also, old wheels don't have the inner seating bead. I think this is designed to keep a radial tire from moving too far when the tire is flat.

[Guest De Soto Frank]

another annecdotal reply...

I have been running radials on my '60 and '64 Chryslers with no ill effects... they originally wore 8.00 x 14 bias-ply tires. I have not experienced "wheel-cover creaking" with the '60 Windsor. On the other hand, I always had wheel-cover creaking with my '61 Plymouth, and I always had bias-ply tires on that car, so go figure...

However, an early '50s De Soto still probably has a fairly narrow rim section, which may be too narrow for modern lower-profile radial tires ( 65-70-75 aspect ratio; our old bias-plies had an aspect ratio of about 83%).

Outfits like Coker and Universal are now selling radials for antiques that have about an 80 % aspect radial, so they are more like the original bias-plys in profile and fitment.

I believe MoPar steel rims of the 1950's still had the rim sections rivetted to the center section, and may not be entirely air-tight for tubeless applications...

The "rim-humps" that Barry was referring to are an inner-shoulder on each bead seat, designed to keep the tire from being thrown from the rim during a tire failure; Chrysler referred to these as "Safety-Rims", and most Chrysler Corp vehicles used them after about 1940.

There are stories out there about guys who experience rim-failure after mounting radial tires to their OEM "bias-ply" rims; I do personally know of one individual who experienced this on the Mass Tpke with his '53 Chevy sedan delivery... apparently the rim "split" right through the center of the rim section. He had mounted radials on his original 15" Chevy rims.

I've seem some cars at the Scranton Region show running the 16" "antique" radials, and the owners seem very happy with them.

I cannot afford to spend $200/tire for "antique" radials, so I just keep bias-plys on my '41 De Soto...

One thing is fairly certain: our old cars were engineered for bias ply tires, and will run for hundreds of thousands of miles on them w/o rim-failure issues...

With radial tires on OEM "bias-rims", there always seems to be a question... ?

[Guest imported_PackardV8]

In some cases (but not all) the pre 60's wheels were stamped out of very thin sheet metal. Especialy on 4 cylinder and 6 cylinder applications. HOWEVER, the same car if offered with a V8 might have had heavier wheels. I've ran into this from time to time especialy on Jeep 48 - 65 depending on application.

However, i sincerely doubt that radials mounted on a wheel and driven relative to the original expectations of the car would ever split or damage the wheel.

During the late 60's when radials were offered as an option, and many people went to tire stores for replacements, such radials were mounted on the same wheels that originaly came with bias.

I have radials on my 56 Packard rims and have often ran upwards of or a little in excess of 100 mph as well as hard cornering here in these Tennessee hills.

We need a technical and rigorous explanation as to WHY this is an issue with older wheels. I doubt that there is such an explanation. OR to put it another way: Never ask an encyclopedia salesman as to wheather or not u should by a set of encyclopedias.

[Amphicar BUYER]

The rims designed for TUBELESS tires are different from TUBE TYPE rims. The lip is there to keep the tire from rolling off the rim in hard turns such as you may experience in an evasive action. You should always install radial tubes when installing radial tires on older style rims to avoid this situation. It has happened!!. There is no difference between radial and bias rims, only tires.

[Fred Zwicker]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The rims designed for TUBELESS tires are different from TUBE TYPE rims. The lip is there to keep the tire from rolling off the rim in hard turns such as you may experience in an evasive action. You should always install radial tubes when installing radial tires on older style rims to avoid this situation. It has happened!!. There is no difference between radial and bias rims, only tires. </div></div>

<img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" /> Please clarify... In your first sentence, you say that the rims are different. In the last sentence, you say that there is no difference between radial and bias rims. Am I missing something?

I have been talking with Diamondback Tires, who say that their radial tires do not require tubes. To be doubly sure, I called them and talked to someone who seemed to be in charge, giving him my make and model car. He repeated again that their tires positively do not require tubes if used on my 1939 LaSalle. Accordingly, I ordered a set this week. My plan is to sandblast the wheels and fill any minor rust imperfections (if any) and then primer and repaint the wheels first. I will then ask my local tire company to make the final decision as to whether radial tubes are necessary with my new radial tires. I am banking on the fact that the wheels on my car are probably very heavy steel and should not flex like on some other cars. There is a long thread on this on the Cadillac-LaSalle Forum and many say they have no trouble at all with radials and no tubes. Others say there could be problems.

Also on the same forum, some say (when using radials) they are losing a hubcap on occasion, while others are not. I have large wheel covers and have installed a set of 16" beauty rings on the wheels as well. The 16" beauty rings slightly overlap the outside edge of the wheel cover and I am hoping that this will help hold the wheel cover on, after I make the change to radial tires. Click on above Attachment to see photo of the wheel cover with beauty ring. Any other ideas? Thanks!

Fred

[Guest imported_PackardV8]

Wheel flexxing is a WHEEL AND WHEEL only characteristic. During (about) the late 70's or early 80's i believe it was Chevrolet that had wheel flexxing troubles due to light gauge wheel material.

If u can keep (anything) from bending (flexing) then u can keep it from breaking.

[Guest imported_PackardV8]

Tip: I'll have to double check my wheels but if i remeber right the ca. 1973 chevy (FUL SIZE CAR) wheels have a small pimple stamped into the wheel just in front of where the gripper tabs of the wheel cover grip the wheel. U mite consider using an arc welder or some other suitable method to create similar pimples on your Cadillac wheels to retain the wheel covers.

I'll look at the wheel collection i have today or tomorrow for more details.

[Guest Randy Berger]

I run radial TUBELESS tires on my 56 400 which has original wire wheels. Normally they require an inner flap and tubes, but the fellow that rebuilt them also sealed them for tubeless tires. I have driven them for several years and only had one problem and that was with the tire itself. PackardV8 gives good advice when he says not to ask the salesman whether you need his product or not. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Guest De Soto Frank]

John,

Chrysler Corporation developed their "Safety Rims" (with the "inner humps")at least ten years before tube-less tires came along. My '41 De Soto has Safety Rims ( humps).

Prior to "Safety Rims", in the event of a blow-out or sudden deflation while the car was travelling at speed, there was a tendency for the tire casing to first ride down in the center well of rim, then crumple-over ( tires had very soft sidewalls then), and frequently get squeegied-sideways, and partially or completely thrown off the rim. This caused very erratic handling to say the least.

This very event happened to Chrysler senior engineer Carl Breer while he was driving "one of the new Airflow cars at over 70 mph" on a Florida highway(c. 1936) - a tire went flat and came part-way off the rim, and made for some scary moments as he was getting the car stopped. When he returned to Detroit, he looked into the matter right away, and the development of the "safety-rim" was the result.

The biggest difference between tube-type and tubless tires is the bead design... tube-type tires are a much looser fit on the rim than a tubeless tire; I speak from experience trying to mount both styles of tire on the same rims, using both manual tire machines, and just tire-irons.

Whether or not there are truly "radial rims" and "bias-ply rims", I cannot say... this is another one of my personal "generalizations", like "12-volt wiring" vs "6-volt wiring"... <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

Trying to get a straight answer from tire dealers/manufacturers about whether or not its "Safe" to put radials on older "bias" rims is difficult, because they're all wary about claims vs liability.

Recently on an antique truck forum, there was a long thread on whether or not 20" multi-piece ( "split-rims") had been banned from public roads... the long and short of it turned-out to be that there were a number of OSHA issues regarding tire mechanics that had been injured while working-on these type rims in the early '70s, and OSHA was pushing for a nation-wide ban on "split-rims"... they didn't get it, so they then placed that liability monkey on the back of the tire dealers, with the result that most tire dealers will no longer work on multi=piece truck wheels...

If there has been a definitive study about mounting radial tires on pre-radial era rims, it would be nice to know what has been found out.

So, at this point I guess I will stop contributing to the "opinion" side of this story and see if any hard facts turn-up...

I do know that my 1941 "bias-ply" rims have run fine for 66 years on bias ply tires, so I'd say that that combination is "proven".

[R W Burgess]

Frnk. A cage was designed to pump up tube type trcuk tires, and most every heavy duty shop has one. They must be put in the cage before pumping them up.

Wayne

[mastertech]

I have mounted many of split rims and they will come apart just driving down the road, or when putting them on the truck. You have to make sure the rim is clean and the lock ring is not deformed. Even at that they will come apart. Had a friend who had just mounted tires and was putting them on the truck and one came apart in his face busted him really bad. I had one come apart just sitting on the floor no one got hurt just a loud noise, had an old time tire man tell to always put the tire upside down on the floor that way if it did come apart the ring wouldnt fly. The other day had a car tire blow apart whe the kid was airing it up, seams he had snaged the bead and when he put air in it the bead blew apart, he didnt get hurt, but it sure smelled funny around the tire machine for awhile. Even used starting fluid to set the beads on had to set tubless tires mostly big truck tires, just spray sone inside the tire leave a trail away from the tire and light itand hit the air when it exlodes setting the bead, too much and the tire will jump into the air if not enought start over.

Put radials on the Desoto wheels usesd the P-size tire but ran into a problem seems the tire baloons out at the side wall causing the tire to rub on the outter tierod end. (only mounted ont to try) Guess i will get the bias tires after all.

[Guest De Soto Frank]

The trouble with modern conventional radials on "real antiques", like most pre-1955 cars, is the modern tires have a much different "aspect ratio", which is the 60-70-75 number expressed in a sizes such as 225-75R-15: this means that the tire section height is 75% of the section width at the widest point of the tire cross-section.

The old-time bias tires had an aspect ratio of about 83%... there are few "modern radial tires"

(that you can buy at Sam's Club or your average tire dealer that have an aspect ratio highger than 75... and the few that do come in 80 or 85 are usually truck tires. ( I am actually going to be going with 235-85R-16" on my '89 Chevy, because I want a really "tall tire" w/o the excess width; but these would be WAY to wide and too tall to think about putting on my '41 De Soto's 16" rims.)

So, usually, when trying to get a modern radial that has enough sidewall profile height, it winds up being either too wide for the rim and/or rubbing the steering components or frame. ( It is also possible to go too large with bias ply and wind up with rubbing too... I discovered that trying to run some L-78's on my '48 NYer...)

That is one of the nice features about tires like Coker's new line "antique radials", that are a true radial tire, but with the taller sidewall, and narrower tread, that is quite close to the old 83% aspect ratio of the the OEM bias-plys. The biggest downside to them ( in my mind, right now), is that they're about $200/tire by the time you include the tax and S&H... ( perhaps if "we all bought them", the price would come down ? <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" /> )

Good luck with your De Soto tire hunting... it's time from some new front skins for my '41... 'nother pair of 6.50 x 16 Lester's for me, for now...

Frank McMullen

[Guest black56hawk]

You can always run a later wheel. AFAIK, a 51 De Soto has a regular Mopar 5 lug, 4.5" bolt circle. I'm running 70s-vintage Mopar 15 x 6.5" inch wide wheels on both my 56 Plymouth and 56 Studebaker Golden Hawk, with 215/75/15 BF Goodrich branded wide whitewall radials sold by Coker. Both cars drive and track much better with radials, and the wider wheels probably help, too.

[Pontiac59]

Even radial wheels flex, I can't keep full size caps on a 1989 Suburban, but I kept them on stock '60 Pontiac rims fine. Pontiac used rims that would have clips for the dog dish caps, through at least '61, an older design.

Some claim that radial tires will cause problems with kingpin suspension cars, although they seem to run them on hot rods with early Ford type axles, no problem. Supposedly they will handle goofy, especially on grooved pavement. While not a kingpin car, I ran them for over 30,000 miles on that '60 Pontiac, no problems.

If you are only driving your car occasionally, stick with the bias plys. Radials will flat spot and especially some of the old-car styles are not made for fast driving; when they sit and age they can come apart on you. My Suburban had like-new tires on it, but had been sitting two years when I got it - about 6 months later, on the interstate at 70 one front tire just let go - it was hard to tell when I stopped but it appeared to have just split apart. I've read of other people having those problems, in one case the tire exploded on the car when it was parked in a garage. I'm sure not all radials will suffer from this problem, but you can run bias plys with tubes until they're so dry-rotted they want to fall apart and are as bald as Telly Savalas - unless you're running the car daily you may as well stick with them.

[1945Dodgeowner]

Check out the Coker Tire web site at www.coker.com

Their prices are good and they have every type and size of tire you could possibly need.

Definately worth a look. Wouldn't want to risk putting on radials and finding out later that they won't work. Not worth the headache.

[ted sweet]

radials dont have nearly the flat spot issues that bias plys do.