Originally Posted by
FBinNY
One trick when mounting tires and tubes is to establish a reference between the two. You can do this any number of ways, such as putting the tire label at the valve, or making a small mark on the tire wall also at the valve. This will save time and help you locate sources of punctures because once you find the leak in the tube, you'll know where on the tire to look for the cause.
A common shop practice is to place the portion of the tire that indicates proper pressure next to the valve stem, on the drive side of the bike. That accomplishes the above goal and makes proper inflation easier as well. If not already mounted that way all you have to do when diagnosing a flat is to leave the tire on the rim and then place the tube back next to the tire/wheel as you reinflate, so that once you find the hole you can find the matching place on the tire/rim.