Tire pressure [Reifendruck]

[q_FTS_p]

if I lower pressure will not i get contact with rim and obstacle? when riding on high speed when you hit bump or on big jump or on flats? :| even when going fast on stairs ?

I have pressure this high because I think it will protect rims

That's right.
But it doesn't make sense when you run that high pressures in your tires, because you will lose to much grip. Usually DH-Tires have pretty stiff side walls and the possibility of flats is even at low tyre pressures (1,5-2,5 Bars e.g.) not high.