Q These days we hear a lot about keeping tires properly inflated to get maximum fuel efficiency. Which is the proper pressure: The pressure the car manufacturer recommends on a sticker inside the driver's door, or the maximum tire pressure listed on the sidewall of the tire? The two pressures are nowhere close to each other.

 

A Follow the carmaker's tire pressure recommendations. Or simply make sure the tires on your passenger car are inflated to 30 to 35 pounds per square inch (psi) cold -- a good balance among wear, steering response, temperature control and ride quality.

 

The pressure listed on the tire's sidewall is not a recommended inflation pressure. If you look carefully, you'll see something like "max load 1,190 pounds at 44 psi." This defines the maximum load the tire can carry at its maximum inflation pressure. This is a description of its load-bearing capability.

 

Check your tires at least once a month.

 

Q I have a '99 Chevy Blazer 2WD, and I'm trying to replace the front brake rotors. They seem to be rusted to the wheel bearing hubs. I tried pounding with a 5-pound sledgehammer with no luck. Any ideas on how to remove the rotors?

 

A GM used two different front rotor/hub setups on these trucks, so make sure you're trying to remove a rotor that slides over the wheel studs rather than an integrated hub/rotor assembly that requires removal of the wheel bearing/hub assembly.

 

I've never seen a separate rotor that wouldn't slide off the wheel studs with just a moderate amount of persuasion. You could try penetrating lubricants such as Deep Creep on the wheel studs and around the center flange, and you could try a little help from the "smoke wrench" -- an oxy-acetylene torch. But, as I said, I've never seen a rotor require this much effort to remove. Worst-case scenario? Unbolt the entire hub-and-rotor assembly and take it to a machine shop.