Why does my bike tire pop ALL the time?

Is there any cracking in your tread? Is there any cracking/protrusions in the rim? Are the spokes flush (or slightly recessed) in the rim?

do you have a 'rim strip'? that protects tire from ends of the spokes? looks like a big rubber band but not rubber goes around rim on inside spokes cannot touch the tube at all all it takes is one sharp spoke end touching the tube == I used to do a lot of bike riding around town and I would get a popped tire seriously every couple of weeks. Now I might need my bike to get to work so I really have to fix this problem. Both the front and back tires popped frequently. I replaced the innertubes myself every time. ==you could fix them for about 5p each time Then I would walk the bike to the gas station to fill the new tube with air. ==get a pump! seriously with a gauge this may be the problem not enough air, inaccurate gauge, hit something hard , a hold, presto a flat When I looked, I could find a small hole in the popped tubing. ==do you ever see 2 holes? that is from low pressure It can't be from running over something sharp, not that often! ==beg to differ I checked carefully in the rim and tire and did not find any objects that could have popped the tubing. There must be something wrong with my bike or something I'm doing wrong, but what could it be? ==sharp edge or something, if so the holes will always be in same place Additional Details I just checked and now I remember I just bought a new tire for the one that's currently popped, so it must not be the tire. I do have a rim strip. The spokes look OK to my untrained eye.... ==rim strip must be perfectly in place 40 minutes ago There are bumps in the rim strip where the spokes are but nothing sharp. Is that normal or could it be a problem? Doesn't seem likely to make a tiny hole though. ==not unless metal is poking through =could be around the valve stem, sometimes there are burrs and sharp edges there but all the holes would be there or most would be wle