I mixed radials and bias plies (and need to change my shorts)

I know this has been touched on before and the discussion goes back and forth, with opinions and theories but here's my first-hand results.

I bought a pretty well built 29 Model A on a new 32 frame.
It has new WWW bias ply 6.00-15's in the front, and in the rear it had some ancient recapped Firestone racing tires. They were rock hard, and totally petrified. One had a hole in the tube but is so hard it ran fine with 0 PSI in the tire. I guess they were the first run-flats.
They are cool looking but when doing a burn out, they just made rubber dust, not smoke.

Anyway, I had a pair of Coker WWW RADIALS mounted on Ford wheels sitting around waiting to go on my Edsel.
So, I decided to put them on the back of the '29.

Wow, it's squirrely. It feels like the rear wants to p*** the front and the car is all over the place. Especially when taking a slight curve, it reminds me of one of those driver training cars on casters. In a straight line, it requires constant correction and uses the whole lane. It must look like I must be drunk. It's pretty scary.

Gotta get some bias ply cheater slicks this week.

 

I found out the same thing many years ago.
Nice to know that you're okay. Can get real
interesting, real sudden like.

 

I added my 2 cents to a couple posts asking about it. Seemed the guy debunking the story always got listened to more. Glad you shared your experience, I have done this one myself too, and it is an experience.

 

its a trip isnt i had a guy tell me on day to put bias on one side of the axle and radial on the other for him that it would be fine he came back and said that it was all over the road shaken and **** ....told ya so....

ive ran bias up front and radials in the rear vis-versa adn never had any problems but the tires i had in the rear where woren out lite truck tires

 

I ran into a lot of that when I worked in a tire shop and guys would try to run their old bias snow tires with radials. More than one needed a laundry change after trying that.

 

If I have to do this, I run radials on front and bias on the rear. This way the car go's where I point the front wheels.

 

I have radials on the front and Bias plys on the back also, and I can agree, running them switched would be scary, with just the few scares I have gotten.

 

I had a flat one day in my 60 Chevy and i had to use an old Biasply spare that i had on one side of the front and a Radial on the other to get somewhere .I tell you i had gray hair when i got home.It would drive okay for a minute or two and then it felt like someone jurked the steering wheel (sometimes towards the oncoming traffic and sometimes to the shoulder).I thought the pitman arm was loose or something .I wish i would have just walked instead that day.Everything bad you have heard about mixing radials and bias tires is absolutly ****ing true...

 

Yeh, anyone who says it doesn't make a difference hasn't been there and wrecked that yet.
30 years experience in the automtive trade says otherwise.
Radials on the front with bias on the rear = OK.
Bias on the front with radials on the rear = a new carnival ride.
I could guess as to why, but I am settling with "it is what it is". Would be cool to really know why though.

 

I seen a fella do it on a paved oval stockcar (streetstock) before,I guess I don't have to tell you the out come of that one.....Lots of bent sheet metal

 

I've run big trucks with radial rear/bias front with no problem. That said, I blew a tire on a VW Bug, and put a radial on the left rear to get home, 4 miles on a gravel road. That ****er tried to kill me every hundred feet! At 15 mph, it went sideways out through the ditch as soon as I hit Second. Idling along in first gear the rest of the way, it felt like it was gonna flip over and die right in the middle of the road. Never again!

 

Over here it is illegal to run radials on the front with bias/crossplies on the rear (unless the rear tread is at least 12" wide). It was common to use 155x15 Michelins or Firestone radials on the front with Mickey Thomson Sportsman on the rear, and I had no problems with that format on my Pop. Well, unless it was a bit wet out!

I think it is legal to use radials on the back with 'plies up front, on the basis that the car would tend to understeer in corners, which is better under most cir***stances than oversteer. Not sure that this ties up with what some of you are saying? Bottom line is that it is probably best to use the same type all round.

 

Yes, it felt like like something broke and the rear axle housing had come loose and was ready to fall out.

 

maybe it's just the weight of the car. Mine is really lite (about 1900 lbs) I run 5" X 16 bias on the front and recapped Hursts 8" X 15 on the back for several years without a problem.

 

I am not really sure what would happen if you had radials on the front and bias on the back ,or viseversa .I do know from expierence that its a widowmaker to mix them from side to side on the front.My 60 drove like a dream with radials all the way around ,but like i said before dont do it from side to side.It takes alot to scare me in a car ,and i have drove some **** in my day that others wouldnt go around the block in ,but driving with a radial on one side of the front and a Bias on the other is terrifying .When it would dart from side to side without warning (and you never knew which way it was going to dart) ,it took all i had to try and get it under control at 45 mph...

 

I tried the "bias on the front; radials on the rear" on my '40 Ford Tudor when I was in high school.
And like the rest of you have stated; "It WAS FUN!!" (especially in a slow turn!)

But like Skip says, "It would be cool to really know why though."
You have to wonder why; RADIALS on all FOUR wheels; work just fine - BUT, they get "squirmy" mixed with bias ply.

My "peanut brain" tends to think; FOUR RADIALS would be even WORSE!
Anyone got an explanation??

 

The side walls on radial tires flex alot more than the sidewalls on bias tires, hence the brown racing stripe you get in your underwear.

 

Ive had bias ft/radial rear on my shoebox and its been fine.
Mind you i dont expect it to handle well anyway so i take it kinda easy, but ive never had any type of problem.

 

"bias on the front and recapped Hursts 8" X 15 on the back " Just did a hundred miles in a car today with that setup, no problem. Even hit some rain.

 

So outside of that Mr. Lincoln, how was the play?

 

I think the recap part mellows out the disparity between bias and radials. I am the third person on this thread with radial recaps on back and bias in front with no squirrelly issues.

 

I received and installed my Coker Firestone Dragster belted cheater slicks today.

MUCH better! -- No more squirming, twitching and wanting to swap ends a lot less burn-out too.

 

I have had two pro street type cars over the years, ran radials on the front with M/T bias on the back. You could run 75 on the interstates, no problems till it rained then you just park or wreck. I DONE BOTH.

 

I had bias plys on the rear and radials on the front of a 1972 Lincoln town car one summer, and it was FUN to drive! The rear kept wanting to come around, which as a teenager I thought was really cool. HOWEVER, that was a very heavy, long-wheelbase car with a very soft suspension.
A year or two later I had bias plys on the front and radials on the rear of a 1971 Skylark, and it was not fun. It didn't dart around like your light, short little roadster, but it took a lot of steering to keep it straight. I put the radials on the front a week later (when I had the money to do it) and the car drove and handled sooooo much better.

 

I bought a 1965 Mercury back in 1983 (when I was a young pup), unbeknownst to me it had radials and bias tires mixed together. Only took it for a couple of blocks on the test drive and bought it. Started driving home and thought "what the F did I just buy?!". Took it to the tire shop and they looked at me like I was a dumb****. Hey, at least I learned something that day!

 

Ive been driving all kind of cars and motorcycles for over 40 years, (yes I'm old). About the mid 70s I put 4 new radials on my 70 Camaro SS, that I bought brand new with belted wide ovals. It was like the feeling of having *** with a REAL FEMALE compared to your right hand.


Ago

 

Also, don't run stagger(too poor or lazy to buy the right size) in icy weather. I did a tour of 2 bridges without a scratch! How I don't know.

 

As a "tire guy" for 35 years, maybe I can answer "why".

If I recall correctly the engineering term is "slip factor" or "slip angle" and can be measured. The difference in "slip factor" is inherent due to the body ply angles in bias versus radial.

The radial ply runs "radially" straight from one bead to the other, and allows the sidewall to flex and roll over further from side force until it reaches its "slip factor/angle" and the tread breaks loose and slides. The added belt package on a radial tire is there to keep the tread flat, letting just the sidewalls flex.

The "bias" body ply runs bead to bead on a bias or angle, and the body plies overlap at intersecting angles, giving a more rigid sidewall, and more resistance to roll. The bias tire reaches it's "slip factor/angle" faster than the radial and will lose lateral tread traction sooner.

Weight bias, tread width, aspect ratio and compound obviously play a influence, but basically that's it.

 

I used to run raider m/t rear slicks 10'' wide and bias ply front radials with out a problem. now run coker firestone bias ply fronts without any problems also

 

i tired bias on the rear with radials o nthe front of my mustnag, it was horrible. never again. i guess each car is different, but that was not a fun ride.