Just replaced tires on 1999 S10 - dealer said they don't make a truck tire anymore that is size that came on S10 - 205/75R15, so he talked me into putting 225/70R15 on the vehicle - now I hear and or feel a constant bumping that seems to come from the rear - told dealer and he rebalanced after one week, now feeling is worse. What to do? Is there a passenger car tire available in correct size? Have put passenger car tires on other trucks and they have always been fine.

 

Welcome to the forum. I think the tires are too wide and rubbing against something back there. 205/75R15's are readily available in tire shops. The service department should have sent you to a place that has them or sourced the tires for you. Go back and ask them to correct their mistake.

 

My 99 s10 came from the factory with 235 75 15s. Never any clearance issues.
Something else is causing your problem, not the tire size.

 

You probably have different rims (different offset to be exact). Post some pictures of the rear-end of your vehicle and the wheels.

 

My wheels are the factory stock 15 x 7 with 6" backspace teardrop style alloys.
I think it depends if your truck is 4wd or 2wd as what tires are stock.
Mine is 4wd.
Don t know how to post pictures, im a dinosaur.