Hello,I bought a set of 15x7 rallye wheels and have cooper cobra tires mounted on them.I love the look of the Goodyear Polyglas but tires are very expensive and they say ride quality is not so great so I went with the modern radial. A couple of weeks ago I was able to buy a new complete set of four new repo Goodyear Polyglas and another set of 15x7 rallyes and was wondering if alignment would be different for the different type of tires. I will run the modern radial most of the time but will put on the Goodyears for certain car shows.Any thoughts? Anybody else switch back and forth? Thanks,Mike.
I would say that the alignment would be different. I have PolyGlas on all my cars, and the guy that does my alignment says that the old style tires are susceptible to wondering to the right because of the roadway being crowned in the middle. He has to adjust the alignment to compensate for that crown.
technically..... yes, all the alignment should be set differently.
when running radial verses bias ply (polyglas) tires.
not just a toe'n'go but caster and chamber as well
possibly even the "ride height" if you run out of adjustment when setting caster and chamber.
of course you can find a "happy medium" and leave it no matter what tires you run, and some will say set it the same either way but to have the correct contact patch, front end geometry ,handing (slow to fast MPH) cornering and track correctly, each type of tire should have an alignment and will be set differently.
so, I would say if you are only putting on the poly's for shows for that look, and not for driving, and doing 99 percent of the driving on radials, then set alignment for radials.
I agree set it with max castor 1/2* of - camber & 1/16" toe , live with it when the bias ply tires are on the car
Part of the improvement of the handling achieved by radials is they tolerate a wider range of angles without showing unusual wear, thus allowing much more aggressive specifications. A bias-ply will not. I agree with others to use radial figures if that is where most your driving is done. Just understand that while the bias tires can be bolted to that, they may protest by eith squealing on turns, wearing quickly on shoulders and tread face or all of the above.