I have a mountain bike and recently the rear wheel has gone flat and every time i pump air into it up to 50 psi it deflates after a few minutes I also hear air coming out a certain part of the wheel but i'm not sure what to do since this is my first time that I have gotten a flat wheel
Edit: I took apart the wheel and found a tiny hole in the tube, should i replace the tube or patch it?
Find what caused the hole and fix the issue. Remove the thorn or glass, etc.
Check this answer for how to find the flat cause.
Patching is cheaper but requires a little skill.
New tube is easier and more expensive.
Check this answer for how to fix a puncture.
Flats are part of owning a bike. Fixing a flat is a key skill.
There are right ways and wrong ways of putting a tube in a tire.
Sheldon Brown has a complete write up on tires, flats, and installation.
