Mixing bias plys & Radials ???

After 30 years in the tire business, here's my input.
The construction of the tire and how it responds to side loads during cornering is the major reason not to mix. The more compliant raidal sidewall construction allows the tire to "lean" more in response to the load shift before the tread reaches its side tractive capability and lifts or scrubs. If the same side load is applied to a bias ply tire, the LESS compliant sidewalls will lift the tread contact patch sooner and begin the scrub or slip. Other factors enter in, i.e. weight distribution and contact patch size, obviously. The fact remains that with the SAME size tire, the bias will break loose before the radial. If the bias are on the rear, it will come around; if on the front, understeer or plowing. It's all in the "slip angle" of the two totally differant constructions.

 

That makes sense, hrA.

 

The real reason the tire manufacturers don't make radials for Bonneville is simple- MONEY

It cost lots of money to design and set up a radial tire manufacturing line- my SWAG is several hundred thousand to a million for small production runs - so how would they ever get their investment back by selling to a couple hundred (at most) teams who use maybe one set of tires a year at Boneville- the economics just don't make sense

In areas where tire companies spend lots of money designing and building tires and want reliable high performance tires- (F1, CART, IRL NASCAR) radials are used solely- there hasn't been bias ply tires used in those series in almost 10 years

and since the molds already exist for the bias ply tires they keep making small batches of tires when they run out of tires to sell - (they're really just repops)

 

[ QUOTE ]
Mixing radial and bias IS a bad idea. It's not something dreamed up by the tire companies or lawyers in their leather chairs. It true that people mix tires and have no problem at all, that's purely luck.

Typically you always want to put the lowest grip tires on the front, no matter what type they are. In all but the most extreme cases this means the bias up front. This holds true when replacing only two tires on your car. Always put the new ones on the rear. I realize that some people may think they need less performance on one axle to balance a car. This is far from the truth. In orer to balance a vehicle for handling you should always improve the axle you feel needs more grip.

As far as handling at the limit, radial tires win here for sure. Radial tires will give you a much more controlable limit than bias tires. They will communicate with you better and let you pass the limit then reel it back in much easier than bias tires which tend to rely heavily on compound only instead of the whole tire for it's limit performance.

In fact in all performance matters radial tires will win.

Now does this mean that everyone should run out and buy new radial tires, of course not. Performance isn't the only factor, in fact sometimes it isn't a factor at all.

[/ QUOTE ]

I know this guy, he's made his living roadtesting for a very large tire manufacturer, now he's roadtesting for one of the big US automakers.

knows what he's talking about.

 

Just for the record, are we talking about mixing bias SLICKS with normal radials...???

Or standard-sized bias-plys with normal radials...???

or both...???

Isn't there something like "diamond-ply" tires...??? i remember seeing a THIRD kind... I want a variety on my car...

And i have skinny-assed 40 year old x-plys on the rear, and newer radials on the front... How will my demise come about, again...???

And all this wouldn't be an issue if radials didn't look like shit....

 

There´s a huge different in bias ply´s, dont bye the chepest ones, and there´s really bad radials too, a cheep hard radial will last forever but gives no warning at all before it let go...
The tires with dimensions like G78 and such (called belt tires here) are a mix between bias and radials and handels worse than both of them...
I use bias plys becouse there quiter,give softer ride, better for the steering/suspension parts, better looking, and more fun to drive on gravel roads (wich there was made for)

Bias plys is for driving and radials is for riding, i like to drive...

 

its good to look back

 

I have driven ONCE on radial front/bias rear.....bad, just didn't know what it was going to do next.
The same car ('60 Impala) with 4 radials was fine.

 

I've been driving for years with radials in front and bias in the rear. The rear are hoosier Quick time pro tires, and are run at 15psi. Yes it likes to wander, but you get used to it. Around town it's fine. If I was to go on the highway I'd choose a Radial, but mind you the sidewalls are super soft on these tires, far softer than a standard replacement bias ply tire.

 

I was going to ask WHO brings up a thread from 2003 but I noticed you are from North Dakota...........................

 

FNG's, it dont matter where, just FNG's

 

Famous last words?