Bias to radial--is re alighning nessesary?

Switching from bias tires to radial. Do I have to have front end set up differently? (toe -in)

 

I would say no,the front end doesnt know what kind of tires are on it.

 

You shouldn't have to. I never set cars different in the 70's when I was doing alignments in a Firestone store and we started switching them from bias to radials.

You might want to check the toe in and make sure it's still where you set it though.

 

It used to be slightly less on radials. If it was 1/8" in with bias ply tires, it would be zero with radials. This used to be on the charts that came with alignment machines years back.

Bias ply tires tended to make the toe-in go the other way slightly as they rolled.

Bob

 

Uh...... NO!

 

1/8 for bias, 1/16 for radials.

 

will it drive without it ? yes. will the tire last longer and the car handle better if you do? yes so the answer is YES you should

 

To me, bias-ply tire are for those 100 point show cars. If you want to drive and enjoy your ride, go radial and screw "correctness".

 

yes.. less toe in for the radials. set at 1/16" toe in.

 

Thank You.

I ran my T for 5 years with bias ply and never had a failure. But the ride is OK but not up to even what my old Jeep does as far as smoothness.

so after 5 years of getting it sorted out and getting it as good as I could, I Just went radial. Last week we had a 50* day and I went for a short ride to try them out. The difference is amazing.

I did not change the toe. Just to see what just the tires accomplished. Before the season gets here I will check the toe and maybe close it up a little.

One of my reason for the radials was that I successfully ran the Bias with no failures for 5 years and I felt that the clock was ticking on having a road failure. With the tubeless radials I can at least get a plug in the tire and blow it up with fix-a-flat. We have really ****ty roads here with potholes and debris. A lot of drywall screws on the road falling out of pickup trucks.

Frank

 

I would prefer to have an alignment shop do mine,but they seem to go by degrees -----sooo how many degrees is 1/16 of an inch?????

 

How is the alignment now? Is it "perfect"? How long since you had an alignment done?

You don't have to have an alignment done when you buy new tires. But if the alignment is off, now is the time to correct it before you wear your new tires.

Check the front end, ball joints, king pins etc. How are the shock absorbers? If they have more than 20000 or 25000 miles on them they are due for replacement. They may not be leaking or worn looking but you will feel a difference with new shocks. That soft "new car ride" will come back.

On an old car without power steering you can sharpen up the steering and make it easier, by cutting down the caster to practically nothing. If you do this you should add a steering damper to prevent shimmy. German cars were set up this way for years. If you examine an old Mercedes or BMW or even VW there is nothing special about the steering and suspension except they all have a steering damper and they are all set up with minimum caster.

I know guys who have gone over their front ends, replaced worn parts and shocks, had an alignment done and were totally amazed at how it transformed the car. Doing this took away all the desire to install a new clip or front suspension and of course, it was about 1/4 of the work and expense. This even works on 40s and 50s cars that never came with power steering.

Having the wheels trued up can't hurt either. Most old wheels are at least slightly bent or out of true.

 

No alignment stays perfect for a long time. Pretty damned good gives a good ride coupled with making sure the front end and tires are in good shape.

I used to work with a Bear machine, every morning I set the toe gauges and checked them later in the day as well if I had a lot of alignments going on.

Do the toe on a car, get it right on spec. Drive the car off the rack, go around the block, put the car back up on the rack and the toe won't be where you set it. Just too many variables in how the car sits, how well the steering box is centered, slop (even in new parts) in the components.

Bob

 

Too many variables to even attempt anything angular.

To get cars close, or for use in the pits for stock cars, I would spin each tire and scribe a line on one of the treads on both front tires. Drop it back down level, measure between the scribed lines at the front and back of the tires, the diference is the toe in or out.

Bob

 

With all the other changes we make, this switch is one of the smaller impacts on wheel alignment.

The original specs were designed to give optimum angles while rolling. Since the radial deforms a bit differently they led to small changes in spec as mentioned above.

They usually have a little less toe-in because of they don't naturally toe-out on roll as much.

Also the bias ply contact patch gave you some "pneumatic positive caster" that the radial sidewall prevents.

The older negative caster was two fold, to ease steering effort and to compensate for the contact patch shifting slightly rearward. This low or negative caster will tend to make a radial ply car wander.

So a bit less toe, a bit more positive caster.

That's ***uming that you haven't lowered the car without checking that effect on angles, primarily having the tie rods point upwards causing toe in on bump and generally nasty bump steer habits.

On the degree, rule of thumb on a typical tire size, 0.25 degree = 1/8 inch, 3.0 mm. Degrees are constant, inches go up with tire diameter. SO 1/16 = ~ .12 degree.

jm2c
rh

 

I think when I had it lined up last year they set it at 10*--so might be OK!!

 

I always felt that after a set of new skins I wait about 200 or 300 miles and get it aligned, radial or bias.

 

Which is fine if the alignment isn't atrocious. If a customer was buying tires, I liked to do the alignment with the new tires on the car.

I had one I'll never forget. It was a '67 Nova, it had new tires and I was shaking down the front end prior to the alignment. I found a bad idler arm and a couple of tie rods that were shot. The customer said he would change them and bring the car back next week.

Next week comes around and he's back... the front tires were scuffed like a bomber stock car. He neglected to take a measurement of the tie rod ***emblies before he started.

Bob

 

What kind of front end is under your car Gary, and is it dropped with spindles or springs?

Thanks

Curious Hoop

 

Dropped axle,buggy spring

 

Cool, so Toe is about all you can do easily.

Here is a good article to read.

The radial wants more (more positive) caster and camber if you can get it.

jm2c
Hoop

 

Radial tires need more caster as the tire rolls under more. If possible, add 4 degrees of caster and it will be less touchy and return to straight on it's own. 58-64 Chevy full size will not go that far, not sure on others.

 

I have split bones---not adjustable

 

If it ain't wandering around, pulling, shimmying, or wearing tires, just let it ride



Otherwise we are picking fly poop out of the pepper!!

For the curious sort, if you have an Iphone or an inclinometer

You will need a garbage sack for turning the wheel, a straight edge or short level to use the iphone/inclinometer against the sidewall and my Caster App

And for about 10 bucks you can see where you are.

Hoop

 

Sure they are. It takes a cutting tool, and a welder. That and heavy-truck service facilities have equipment that can align by bending the axle.

 

The article linked here is very good, it lays out the basics in a very understandable manner. It should be required reading for anyone building any sort of ch***is. Yes, minute adjustments do make a difference. Thanks, Hoop.

 

The car steered well and no shimmy,death wobble or anything like that---tires wore evenly----no panhard bar & no stabilizer----that was with bias----All I wanted to know is since I'm switching to radials is if alignment had to be changed

Once I get them on I will check (or maybe have a shop) check toe in----other than that unless I have some sort of problem,I will leave well enough alone

 

I think one of the overlooked deals about Radials is the sidewall deflection in the turn. I think the 70 or so Monte Carlo was one of the first cars to go to the high caster, high camber gain geometry.

Anyways, Caster controls the Camber change in a turn on a beam axle. Each 2.4 degrees of positive caster gives you about .5 degree of "good camber", negative on the outside, positive on the inside of the turn.

Steering Angle, Caster, Camber Change
------- 12 7.2 Deg. 1.5 Pos, 1.5 Neg
------- 12 4.8 Deg. 1.0 Pos, 1.0 Neg
------- 12 2.4 Deg. 0.5 Pos, 0.5 Neg

Obviously Negative caster get's the tires leaning the wrong way in a turn.

So if I had a preference I'd go to about 4 -6 degrees positive in "Theory".

Your mileage may vary.

BTW, about 10 years ago my son was pretty successful in Oval Karting and that is all about caster split, camber split, trail split, and axle lead, we had a lot of fun learning that.

If that's an OEM axle Gary you may want to get a little caster in it, but if it rides good then roll with what you got.

Seems like you asked the time and we got off into the theory of relativity a bit

Hoop

 

I have a set of radials and a set of bias. I change back and forth depending what kind of driving I am doing. I don't believe you will find a need to change alignment. If I want the looks I use the bias ply and if I want something that handles well on a long trip I run the radials. Let us know how you like the Excelciors. I have a couple of friends that run them and they swear by them.

 

Hey! I appreciate all the advice---The main reason I asked is because I bought the Excelsior radials and they about broke my bank They are pricy,and I don't want to have to buy another set in the near future.
I was happy with the bias stones (and they probably look better) but just getting tired of fighting the lines in the road & our roads here aren't the best. And I drive a lot of miles