How do I stop punctures for good? Last night I came out of work to a flat tire. This is the second time I've got a puncture with less than 100km done on a brand new set of schwalbe smart sam tires. needless to say I was quite annoyed. The first puncture happened after about 40km and the second was after 95km, last night. It was the same wheel both times. After the first puncture, I checked and double checked for any foreign objects in the tire and rim and I found nothing. I pumped the tire and kept it at about 55psi because I read this is good for avoiding punctures. All this to no avail.

I'm just wonder what can I do to stop punctures for good? I'm a heavy guy (about 110kg) so maybe this just isn't possible? I've tried slime before and that was useless. I currently ride on Smart Sam 26" x 2.25
There are a few things to do. I'd start by reading this link from Sheldon Brown.


First determine how the flats are occurring.


Inspect the tube. Is the rim tape on the rim properly? (if not, you'll see a puncture on the wheel side)
Is the tube being pinch flatted? (a snakebite flat, two very closely placed punctures - usually a sign of too low pressure)
When you re-install the tube, are you pinching it between the tire bead and the rim? (You can make a rolling motion over the rim with the tire after its seated to prevent this from happening).
If you can't find the puncture easily, pull the tube out of the tire, give it some air and then try to find the hissing. If you can't find the hissing, try passing the tube around your lips or dunk the inflated inner tube into water.

Check the inside and outside of the tire for any embedded debris, carefully. If you find some, remove it. 
If the tube doesn't have any punctures, is the valve good? Sometimes a faulty valve causes pressure loss. You can either re-core the valve in some cases, or more easily just buy a new tube.


Many manufacturers make kevlar belted tires which have stronger puncture resistance (such as the Schwalbe Marathon Plus), but if your punctures are happening due to rim tape or something, then its not going to help.

If you are running such big tires at 55 psi though, I don't think it's low tire pressure -- I've had about 300 pounds of stuff (bicycle, rider, cargo) on a bike with 26x1.9" tires at around those pressures without any problems on some pretty shabby roads.  

If the first flat was indeed a puncture due to debris, my guess is that you didn't actually get all the debris out.