"Tom Young" wrote in message
...
[...]
I read somewhere recently (can't remember where now -- magazine article?)
that braking once off the ground with the wheels spinning can make the
tires slip around and possibly shear off the valve stems. Maybe that's an
aviation urban legend, but it seems like it would be an unpleasant little
surprise upon landing. I'd be curious to know if that's actually happened
to anyone.

If that were true, braking while on the ground would cause the same problem.
If anything, the difference between the inertial and friction forces are
much greater in that situation than braking after takeoff.

If it does concern you, apply the brakes gently. It shouldn't take much
force to stop the wheels anyway.

One thing to note: the vibration on a 172 (and similar issues on other
airplanes) isn't the same as noisy bearings (not that I know that's the
issue on the tailwheel that started this line of discussion...that was just
the assertion we started with ). The vibration is because the wheels
aren't balanced, a common problem with training airplanes, due to students
and their poor braking habits.

Pete