If you ride, you should carry the basic repair tools and be prepared to fix a mechanical on the trail. Besides tube and air, I put together a small plastic box or bag of the following goodies. The idea with this list was small light weight but critical items. Others can probably add to the list. chain link / chain pins shift cable chain ring bolts deraileur hanger patch kit (in case run out of tubes) brake pads duck tape or electrical tape multi tool It works pretty good. You never know what is going to happen, but these items can usually get you off the mountian.