What size tires for 72 RR?

[72sspJeff]

Hi Friends:

Our 72 RR came with 15" Magnum 500 wheels and wide tires that rub the wheel wells when we make a hard turn.

I'd like to get the correct size tires for the car and put them on the existing Magnum 500 rims, but don't know what size to get. We want some nice smooth riding radials.

Any help/suggestions are appreciated! Thanks!

[Eric]

I think you're going to have to clarify your question a little in order for us to give you a correct answer.
Are you asking about the factory correct tire size for your car? To the best of my knowledge, no 72 came from the factory with 15" road wheels (magnum 500) only 14". Do you know the offset of the wheels? What is the tire size you have now?

[72Rdrnner]

To the best of my knowledge, no 72 came from the factory with 15" road wheels (magnum 500) only 14"

FWIW my car came with 15" wheels. Not the "Magnum 500" but the "Rallye Road Wheels" (W21) and the G60x15 raised letter Goodyear Polyglas tires. (U86)

I have 15x7 US Indy mags now with P235/60R15 Goodyear Eagle #1 tires, complete with the NASCAR logo. (woo hoo) Have no problems with fender clearance.

[72Rdrnner]

Hi Friends:

Our 72 RR came with 15" Magnum 500 wheels and wide tires that rub the wheel wells when we make a hard turn.

I'd like to get the correct size tires for the car and put them on the existing Magnum 500 rims, but don't know what size to get. We want some nice smooth riding radials.

Any help/suggestions are appreciated! Thanks!

You might want to check the ride height. If it's too low the tires will definitely rub when they are turned.

If you have a FSM it’s all spelled out…if not here’s the Readers Digest version.

You measure from the bottom of the ball joint (which is set by the tire/wheel size you have) and from the bottom of the torsion bar adjuster blade where the torsion bar is attached to it. The FSM spec is 1 5/8 inch difference, with max of +/- 1/8 inch difference from side to side. On my car the ball joint measurement is 9 1/4 inch and the adjuster blade is 10 7/8 inch. Make sure you are on a flat surface (garage floor for instance).

The FSM says you should have "...the recommended tire pressures, a full tank of fuel, no passengers or luggage compartment load and on a level floor or alignment rack."

Jostle the car up and down a few times then take the measurement. I repeated the jostle & measure routine several times until I started getting the same measurement consistently. If you have to make and adjustment do the jostle & measure again on BOTH sides, even if you only adjust one. Took me several tries to get it right. Then after I drove the car some I checked it again and had to make some more adjustments.

I made a couple of shade tree mechanic measuring tools out of plain 'ol pieces of a wire coat hanger. Bend one end over about 1/4 inch (need that so it will fit up in the lower control arm and touch the torsion bar adjuster blade) then cut the other end it to make it equal to the ball joint to floor measurement. Do the same with another piece except cut it so it is 1 5/8 longer than the ball joint one. (the torsion bar end will always be the higher measurement)

After you’re all done keep those fancy tools as they come in handy for checking/adjusting the ride height. Remember if you change your tires to a different size you have to go back to square one and make new measuring tools as the ball joint to floor distance will change due to the tire size change. But hey! Coat hanger wire is cheap and easy to find!

With all this the tires may stil rub due to being too wide, but that's a separate problem. You will still have to check ride height from time to time.