Thread: Why cant you mix bias ply and radial tires?

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I hear that you cant (or not supposed to) use radials in the front and bias ply in the rear, or vice versa. What happens when you mix tire type and why? Thanks

The basic concept is that the tire sidewalls deflect differently, the radials tend to "roll" more than the bias ply in general. The concern is that you'll get unequal turning dynamics front to rear, or side to side, that may make it difficult to control.

Bias ply tires flex more in a turn, a radial pretty much stays true, it can cause issues with handeling around turns.

Biggest problem I've found with radials on the front and bias on the rear is the front end will stick and the back end will get loose real easy. This problem gets to be about 10 times worse if there's a little bit of rain on the road. Hard braking can get to be down right scary!!!!!

Sask. laws allow radials rear, bias front, but not the other way around. I had a VW that had bias, put a radial (spare) on the back, and it tried to kill me the first time I took it over 20 mph! Absolutely uncontrollable. It felt like the back end was on caster wheels!

Radials on back and bias on front will cause understeer. Comversely bias on rear and radials on front will cause oversteer. This goes for wider tires on back and/or wider offset wheels than those on the front even if all are radials. Wider tires/wheels on front are a recipe for oversteer too which is more dangerous than understeer.

To get really technical, it will handle like crap! You need to stay with like tires on all four corners to get the best handle possible out of the vehicle.

I wonder why some school busses and big rigs run bias on the front and radial on the rear, and then there the 1's that run all bias or all radial. anyone know? I don't see the point behind it. almost every full size buss ( International Chassis, bodied by bluebird ) that my school has, runs ither all bias or bias on the front, radial on the back

Originally Posted by Matt167

I wonder why some school busses and big rigs run bias on the front and radial on the rear, and then there the 1's that run all bias or all radial. anyone know? I don't see the point behind it. almost every full size buss ( International Chassis, bodied by bluebird ) that my school has, runs ither all bias or bias on the front, radial on the back

Bias tires for trucks are almost impossible to purchase new any more. All our trucks since 1993 have come with tubeless radials,and 1990 with tube type radial. Also ,it's radial side walls that flex more, thats why they look soft when fully inflated, and require diffrent tubes if installed. Hank

Little off the subject but, I noticed last weekend when we pushed the "Z" into it's parking spot it didn't like to turn too well. Front end as it sits is still light enough to pick up by hand and has skinnies. Rear end is heavier, tires are sticky and it's got a spool. When finished the rear wheels will do the spinnin'/slidin'. Just was funny seein' the front tires slide N' squeal.




Thanks to Dennis Holas for pic #2..

As a temporary measure, I've been running bias front and radial rear. Other than looking pretty bad, I've had no handling issues what-so-ever.

Originally Posted by pharaohchris

As a temporary measure, I've been running bias front and radial rear. Other than looking pretty bad, I've had no handling issues what-so-ever.

Probably won't have any issues in normal driving, stuff in into a corner really hard and you'll understand why it's not good to mix radials and bias tires.....

Hey ProZ, probably would help to get some weight in that front end, Hum ? Man that thing looks wicked!

Somwday

Originally Posted by pro70z28

Little off the subject but, I noticed last weekend when we pushed the "Z" into it's parking spot it didn't like to turn too well. Front end as it sits is still light enough to pick up by hand and has skinnies. Rear end is heavier, tires are sticky and it's got a spool. When finished the rear wheels will do the spinnin'/slidin'. Just was funny seein' the front tires slide N' squeal.
Thanks to Dennis Holas for pic #2..

It will still turn the same when finished.The rear end with the spool will push the front end.