TIRE WON'T SEAT

PROBLEM: You install a tire, pump it up, and a section bulges or dips.

SOLUTION: Bulging is urgent. Quick, let out some air! A section of tube is under the tire bead (the inner edge around each side). If you continue to add air or try to ride, chances are real good that the tube will pooch between the tire and rim and explode.

Once the tube is deflated, work on the problem area. Lift, squeeze and massage the tire until the tube no long appears under the bead. Then cautiously add air, watching to make sure all is well.

On a properly seated tire, the bead line -- the thin line molded low on each sidewall -- will be just above the rim all the way around on both sides.

If the bead line dips below the rim, the tire will feel lumpy as you ride. To correct this when you have a high-pressure floor pump, keep adding air beyond maximum inflation. This extra pressure may pop the bead into place with a snap you can hear (then let out the excess air).

No luck? Deflate the tire and massage the dippy section. Pull it up to the same position on the rim as the rest of the tire. Inflate and all should be well.

Still no luck? Deflate again and rub something slippery on that bad bead. Lots of things can work, but don't use bike grease, which could harm the rubber and get on the rim. Try a little liquid soap, bar soap or saddle soap. Good old spit can work, too, and might be the only choice if this is happening during a flat repair out on the road.

Pump up the tire again. OK? Good! Now skip today's upper-body workout because you just had it.