Would you mix radial and bias ply tires?

S

stevej

New member
Becoming a little disgruntled with Les Schwab’s these days. On my last trip to Newport one of my Continental bias ply tires (less than 2000 miles on it) had the tread separate from the casing on I-5. The tire had been running a little hotter than the other three at about 114 degrees as opposed to 102 – 106 for the others when checked 40 miles earlier. Things started vibrating noticeably looked in the mirror and see the tread flailing around at 62 MPH.

Schwab would not give any credit for the tire and for what ever reason mounted a radial as the replacement for 96 bucks. When I questioned the radial replacement for a bias ply tire I was told that it would not be a problem even though the other 3 are bias ply…..

Always thought you should not mix the two types. Anyone run with mixed tires and is this going to be a problem?

Thanks
stevej
 
If I recall correctly, you are never supposed to mix radial and bias ply tires on the same axle.

I am not a tire expert though. :)
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mike
 
Mixing bias and radial tires isn't as critical on a trailer as on powered applications. That said I wouldn't do it except to get to the tire store.
As far as Les Schwab? They're usually OK but I've seen them pull too many shenanigans to go back. I suspect they didn't have a bias tire in your size and rather than refer you to a store that had one they just took your money. After all, out of town clients don't have to be treated as well as potential repeat customers.
 
You can mix them if you want to crash. Never mix them and here's why. Radials and Ply break and slow at different speeds. a car with radials in the front and ply in the back will swap ends if you get on the break heavy. If you have them on the axle you break a axle as one tire stops before the other.

Now all that said if you have a two tire trailer with out a common axle you can mix tires. Just what i was always taught.
 
Plagiery from THT follows:

Here is a quote from the Michelin web site --

" If two radial and two non-radial tires are installed on a vehicle, the two radials MUST be installed on the rear axle and the two non-radials on the front axle."

and the RMA web site ---
"When two radial tires are used with two non-radials, put the radials on the rear axle."

from Dunlop website
"When radial tires are used with bias or bias belted tires on the same car, the radials must always be placed on the rear axle"

This is for vehicles, not trailers, but the info is good info. Those of us living where brakes are only required on one trailer axle would have zero problems just following the recommendations.

End Plagiary

Don't listen to Tom. Marines know little about brakes and besides, they pride themselves in only going in one direction and never stopping for anything....

Don
 
We pulled our boat cross country when we bought it...Lake Tahoe to Alabama. The four years we lived in AL we made mulitple trips to Florida and pretty much every weekend a 40 minute drive to the lake. Never realised we had 3 bias plys and one radial on our tandem axle Pacific trailer. I simply checked the tire pressure and kept an eye on tread wear. One tire had a slightly different tread pattern, but was the same make as the other three. The previous owner had replaced that tire for us prior to our cross country trip. Turns out it was a radial.

I wanted 4 new tires before we moved to Washington, so I replaced them all with radials and it is slightly better handling at highway speeds. I, too, had always heard mixing was a no-no. Based only on my experience, your mileage may vary, but I wouldn't sweat it too much until you get all new rubber.

Rick
 
Stevej - Sorry to hear about your problems with Les Schwab. Dealt with them for 18 years in Oregon and the last 4 years in Montana without a hitch. John
 
Thanks for the input everyone. Looks like the safe route is to not mix the types.
Pulling the boat to Newport today so I will run with the spare on this trip and deal with it later.

stevej
 
Not that I am a complete expert, but as a former auto tech, and a person that worked in the parts and service department at Camping World for a number of years, I have never heard of an axle breaking because of the type of tire that was put on it. Nor have I seen an axle break when only one brake works on one side of it which you would think would really try to twist them. In reality, they really are pretty stong and durable and the stresses that one can put on them during normal braking is often far less than the stresses that are on them during their normal dynamic load bearing operations that they have going down the road.

As far as having a radial or a bias on a trailer? I would not mix them on the same axle as Tom says. In fact, I generally hate bias tires, so it wouldn't take much for me to get rid of the other 3 on the trailer if it were mine.
 
Hey, I'm no tire expert, but....

I'm guessing that the problem exists because the radial and bias ply tires are quite different animals.

The big advantage of radial tires are that the plies are arranged in the sidewalls radiating out from the axle center with the majority of the tire cords spun around the outside circumference of the tire. This allows the sidewalls to flex greatly, keeping the contact surface (or patch) of the tire in greater contact with the ground, providing better cornering and stopping power.

The older, bias tires have their sidewalls made up of cloth fibers arranged with their threads on their bias (diagonal to the weave and radius of the wheel/tire, and are much more rigid in their sidewall action. This makes the tire behave like it's taller and stiffer, reducing the contact patch and thus cornering and stopping power.

If you were to mix them on an axle, the two would not be working synergistically together, but instead the radial would have more traction and work to scrub down the stiffer bias tire which has less grip and cannot work with the radial in coordination.

At least that's my guess!

Joe. :teeth :thup
 
To continue what I was saying above, but in shorter form, the tires also simply behave differently, in term of ride, accommodation to the road, steering, traction, handling, and much more. They're really very different, even the ride height would be different.

Having a radial and a bias ply tire on opposite ends of the same axle would be like pairing a radial piston engine under the port side wing of an aircraft with a liquid fuel rocket engine on the of the starboard side.

Speaking of such miss-matched marriages, remember the B-36's, JATO bottles, and hybrid powered aircraft of the early and mid 50's? At least they were symetrical.

Reminds me of the blond joke where the blonde is speaking about her dual language fluency in French and English where she says, "Why, yes, I've been bilateral since I was five."

Joe. :teeth :thup
 
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