Do you get flat tires on your bike and don’t know why?

This week’s “Ask the Expert Bike Tech (and Professional Bicycle Fitter)” comes from Bill who asks:

My son’s hybrid bike that he rides around campus is flatting on just about every ride.  It seems to be always flatting around the valve stem.

It is an older hybrid bike, with 700 x 35c tires on it (somewhat knobby tires).  Recommended tire pressure on the tire is 50-75PSI, I suggested he run at the low end (~50psi) of this in case impacts are causing flats, but the flats continue.

This past weekend we ran a new rim tape around, replaced tire, got it back together, his first ride to campus – flat again.  We cannot find any burrs or edges on the wheel itself, and the tire seems fine.

Our resident Bike Guru, Victor, had this to recommend:

If you have any questions about the mechanics of your bike or improving the fit between you and your bike, please be sure to send them in to Ask the Bike Tech. Consider Victor your own private bicycle expert and professional bike fitter.  Send your questions to: darryl@lovingthebike.com.