Replying to Road Bike Issue

Hey guys,

I'm looking for some serious advice here. I've been riding my bike into work lately (about 21 km each way), and for the last 3 days, at some point in the morning, my front tire goes completely flat. I'll do a quick tube change, ride home, get the PSI up to 115-120, ride to work the next day, then have the same problem all over again.

I check my tire for sharps and debris at each change, am careful on my rides to stay on the nice part of the road (no bumps/potholes) yet have this problem. The only thing I can think of is it is sitting on the south side of the building in the sun, and over the day it gets too hot. Anyway - I'm running out of money for tubes and patch kits..

Any thoughts on what causes this/what I can do to stop it from happening?

Thanks