9. Inside Of The Rim
How To: Also inspect the inside of the rim. The rim strip that protects the tube from spokes often moves or stops functioning. If all of this still hasn't helped you figure out why you got a flat, you may want to inflate the old tube to see if you can match up its puncture to where it happened on the tire. You may also want to inflate the old tube to see the size of the hole. If it's a small one, it may be a candidate for a patch.