One of our first business lessons came a long time ago when a couple
came to return two bikes they had bought the previous day, because one
of them got a flat on the first ride. Naturally, we offered to fix it,
but the woman was so disappointed, she just wanted her money back.
After removing the tire from the rim, we discovered that the flat was caused by a low-quality rim strip. A rim strip is a piece of tape, which can be rubber, plastic or cloth, that lines the inside of the rim to protect the inner tube from protruding spoke nipples on a standard rim, or from edges of holes drilled in a double-walled rim. Hardly anyone ever thinks about rim strips, and yet a good one can prevent a lot of unnecessary flats.
Because we assemble hundreds of bikes annually, we've discovered that quite a few bike manufacturers use sub-standard rim strips, causing many new bike owners frustration and disappointment. This problem is by no means limited to cheap bikes. In fact, manufacturers tend to use basic rubber rim strips on entry-level bikes. They can sometimes cause problems, but are not the main culprit.
For some reason, higher-priced bikes come equipped with thin plastic rim strips, which fold over and don't protect the tube, or have sharp edges or seams, which actually cut into the tube, as shown at left.
The experience with the disgruntled customer was a blessing in diguise. Since we cannot possibly check rim strips on every bike, we began to offer free, unconditional, one-year flat repair service with each new bike we sell. This gives us the opportunity to replace those rim strips which cause problems, and gives the customer peace of mind.
If you are getting a lot of mystery flats on your bike, worn, loose, folded-over or excessively stiff rim strips could be the problem. We suggest you replace them with high-quality cotton rim tape, and start enjoying riding.