Wide Tire Effect on Suspension Components

jerryp58 · 01-04-2003, 09:41 AM

Is there any detrimental effect to the suspension components caused by having wider than stock tires on my car?

I'm hoping the answer would be "No, as long as the car is aligned correctly".

I have a very stock '77 with the 8" rallye wheels. I currently have 245/60-15's on it (versus the 225/70-15 stock size) and I'm thinking of putting 255/60-15's since they're closer to the original diameter.

I'm currently dealing with worn side yokes (stub axles) and, even though this is a fairly common problem with these rears, I was wondering if the wider tires contribute to the problem (or any other suspension problems).

Thanks.

tommelton · 01-04-2003, 04:02 PM

Tire width alone should not cause extra wear. What accelerates wear on the suspension parts is incorrect offset. If you keep the same wheels, and just go to a different width tire (assuming ok for rim width), then there would be no extra suspension wear.

But, if you change wheels, and go from lets say, a zero offset wheel (equal front and backspacing) to a positive (?) offset wheel with higher frontspacing and shallower backspacing, then you will wear components out quicker, due to higher stress levels. But, it would be on the rear control arm bearings and the outer spindles, not the inner stub axles.

Tom Melton
82 CE
86 Z51 Coupe with 17x11.5" all the way around and bearing wear!

jerryp58 · 01-05-2003, 11:55 AM

"Tire width alone should not cause extra wear" -- That's what I was hoping to hear :)

I'll be keeping my stock rallyes so my offset will not change.

Guess I'll start looking around for a 255 tire that has a reasonable section width so that I don't have to move e-brake cables or anything.

Thanks for the info,

Jerry

c4cruiser · 01-06-2003, 09:01 PM

255/60's were an optional tire size on the 78 and I don't believe that they did anything different to the bearings or suspension components just for the tire. You may have some clearance problems at the lower sides of the front wheel wells. There should be no clearance problems in the back.

When these tires were fitted to '78 cars on the assembly line in St. Louis, the workers had to clearance the lips of the fenderwells to keep the tire from rubbing on the fenders at full lock. Not a lot of material had to be removed, and not all cars had to have this done because of differences in the way the fenders were molded.

Just make sure to check when you have them mounted. Something like a Dremel tool should be all that is needed to provide any clearance.

If you are replacing the side yokes, it would be a good idea to do the bearings at the same time. Replace the control arm bushings and the link bolt bushings, too. Then if you replace the strut rod bushings, you pretty much have a complete rear suspension rebuild. Then have a good front and rear alignment done.

SWCDuke · 01-07-2003, 02:14 PM

As long as wheel offset remains the same, suspension component loading won't change very much, depending on how much grip the tires have.

If you are looking for maximum grip you won't find it in a 255/60. The best currently available tires for Sharks are 225/70 or 235/70R- 15 V-rated police pursuit tires - GY Eagle RSA, General XP2000V, and Firestone PV41.

Duke

Darkness · 01-07-2003, 06:32 PM

Actually 295/50-15 wont be a bad choice for grip either. There are several forum members that use them on the stock 8" rims (in the rear)

Later :cheers: