Originally Posted by
DallasSoxFan
Makes it harder to puncture. Don't beleive me, think of this...
Inflate a plain old latex party balloon about halfway. Push a pin into it. You have to press decently firm to pop it. Inflate the balloon to capacity. Take the same pin and the balloon pops easy.
Same thing with tubes.
You have to be careful though. Too low a pressure increases the likelihood of pinch flats.