As with all touring designs, ATB wheels must emphasize strength. Quick-release hubs can be used in the lighter pair. Sport and Racing Racing, sport riding, and fast touring can be done on narrow, 20-mm rims unless you weigh more than 200 lbs. This robust setup makes perfect sense with a 20-mm rim, especially if you plan to commute, ride in foul weather, or do some touring. Since fast recreational rides frequently include the speed and excitement of competition, we can take some design lessons from racers.
Recent evidence confirms that their rolling resistance is about the same as tubulars'.
At 440 to 470 grams the lightest clincher rims do weigh more, but it's a slight penalty considering that the tubular rims most teams use weigh a hefty 400 to 420 grams. On the other hand, the weight saved by using a tubular tire and a lightweight tubular rim can give you a substantial advantage if your weight or riding style doesn't endanger the wheels. If you choose tubulars, the next important decision is between 28 and 32 spokes. In top-level racing, the vote runs about 80 percent in favor of 32 spokes. During the next few years the ratio will tip toward 28 spokes, perhaps to as much as 50 percent.