Mtb tires on road rim I got a mountainbike from wich the back wheel completely bent. I can't fix it with a spoke wrench. The tire is a v-brake tire and I had a spare v-brake rim laying in my shed only problem is that it had a road tire on it.
So my question is: could I just put a mtb outer tire on that v-brake rim with the road tire on it and succesfully use it on the trails?
Assuming the new rim is about the same width as the bent one, then the tyre and tube should transfer over okay.
You need to check the valve hole in the rim - there are two common sizes, and the wrong one won't fit or risks punctures at the base of the valve.
I suggest you fit the tyre, and inflate it to a relatively high pressure, whatever's maximum on the sidewall.  Then leave it overnight and check again in the morning.  If it holds air and hasn't blown off the rim then deflate a little to riding pressure, and go for a test ride