Outside magazine, March 1995
The last time you bought a bike, the guy at the shop probably had you straddle the top tube to determine the fit. If there were a couple of inches between you and the tube, chances are it's the bike you're riding now. If you're lucky, it fits.
"That measurement alone is meaningless," says Andrew Pruitt, coordinator of sports medicine for U.S. Cycling, who's fitted bikes to the celebrated centimeters of Davis Phinney and Andy Hampsten. "Even more so now that so many mountain bikes have sloping top tubes -- or none at all." Here are his tips for finding a mount that fits.
The saddle and the stem are the two crucial variables that you'll need to experiment with. Start by adjusting the saddle fore and aft. First, coaches Pruitt, "Let your fanny find its natural home." When you're comfy, bring one pedal to three o'clock. Then have the salesperson drop a plumb line from the front of your knee; move the saddle until the line hangs at the tip of the crank arm. Adjust the saddle height so that your knee is slightly bent when the pedal is at six o'clock. You shouldn't have to tilt your pelvis to reach that position.
Now to the stem. "Reach is the most difficult aspect for me to prescribe, because it's so personal," says Pruitt. Generally, though, recreational riders want to bend about 45 degrees from the waist. Either adjust the height or swap stems at the shop until you find a comfortable position.
If you can tinker with the saddle and the stem to meet the above criteria on two different-size frames, opt for the smaller one. "The smaller bike will be stiffer, so that your work transfers more efficiently," explains Pruitt. And you won't have to discuss your inseam with a stranger.