tire change problems-help!

[orthos68]

Hi Guys,

I have a 1994 Chevy K Blazer- 4wd- 2 door, tires were 245/75-16 purchased Yokohama Geolandar from tire rack 285/60-18. They look great but now the car wanders to either side, seems to follow the crown of the road. Air pressure checked, wheel alignment done twice, shock abosrbers changed, idler arm changed still wandering. Don't know what to do next? Spoke to Yokohama reps recommended 35psi front, 45psi rear, this sounded wrong to me I always thought the front had higher air pressure than rear??? No change in wander.

Does anyone have any suggestions?

Thanks for your help!

Rob

[Grant@Tirerack]

Going from a 245/75-16 to a 285/60-18 will give you quite a bit more tread width and a more elongated contact patch. That combined with a shorter sidewall which will flex less will make the steering very responsive. The problem comes in on older vehicles that may have worn bushings in the suspension. The flexing from an older suspension will be amplified when going to a lower profile wider tire. It will place more demands on the bushings than the narrower, taller sidewall tires. I would start by having the bushings looked at. Even a well maintained '94 is going to be subjected to wear in the bushings as they age.

[CapriRacer]

Were the original tires P metric or LT metric?

It is unfortunate that GM choose to use both of these sizes and create all this confusion.

THESE TIRES ARE NOT INTERCHANGEABLE!!!

But to answer your question. NO, ABSOLUTELY NOT! The rear tire pressures are, if anything, HIGHER.

But the 35 / 45 answer leaves me cold as well. What does your placard say the pressures are supposed to be for the original tires?

And the 18" tires are either P metric or Euro metric, not LT metric, right?