Originally Posted by
Six jours
I regularly ride on dirt paths in the mountains. The roads are often steep, but usually quite smooth, so a mountain bike is overkill. But if you don't ride the brakes on the way down, you go 70 MPH. So I usually find my valve stems going crooked at the end of a long day, and I won't be at all surprised if one gets torn right off someday. Disk brakes would be a welcome addition, at least for me.
Crooked valve stems are usually an indicator of
low tire pressure which allows the tube to move around in the tire rather than high pressure you'd expect from over heated tires.
Secondly, it's damned difficult to go 70mph on a bike. I've tried.