How close to the chainstays is the rear tire? You do have the option of getting an MTB front fork. As another poster mentioned, you really don't want a tire rubbing against a part of the bike for any length of time as it'll quickly wear the tire or cause a lot of heat to build up on the tire and/or tube.

Also, please do check that stem to see if it's above the minimum insertion mark. If it is it could snap off if you hit a big bump, hit a pothole, or simple because it became fatigued.

Cheers