Cycling comfort and efficiency begin with a bicycle that fits right. This article, which includes video advice from REI Outdoor School instructors, explains the basics of bike fitting.
The checklist for evaluating the fit of a road bike also applies to many urban, touring and commuting bikes. Note, however, that the aerodynamic riding position of road biking is not necessarily the most comfortable for extended bike touring or for heavily loaded bikes.
As our video shows:
Check the frame's standover height. This ensures your chosen model is correctly sized for your leg length and flexibility. (See diagram below.)
Adjust seat (saddle) height.
Adjust seat position. Your knee should be aligned over your forefoot for greatest efficiency.
Check the stem. Your stem length and angle determine how far you reach and bend at the waist to reach the handlebars. If you need to increase or decrease the stem length for a comfortable reach to the bars, you will most likely need to have a bike shop change out the stem to one that is the correct length and angle. A few road-bike stems have adjustable angles that allow you to raise the handlebars by changing the stem angle.
To gauge the fit of your stem:
First, check the frame's standover height.
Check the distance from the seat to the handlebar.
Check the seat (saddle) height.
Adjust seat position. Your knee should be aligned over your forefoot to pedal most efficiently. This step is not discussed in our video in fitting a mountain bike, but this guidance (also described in our road-bike section) is valuable advice that should be followed.
Check the stem. This is to comfortably position your arms and torso. (As with point 4, this advice is visually demonstrated only in our road-bike video, but it is true for mountain bikes as well, so we repeat it here.)
Your stem length and angle will determine how far you reach and bend at the waist to reach the handlebars. Some stems have adjustable angles that allow you to raise the handlebars by changing the stem angle. However, if your stem is not adjustable or you need to increase or decrease the stem length for a comfortable reach to the bars, you will need to have your bike shop change the stem to one that offers the correct length and angle.
To gauge the fit of your stem:
A note about standover height.
Adjust the seat (saddle) height.
Check the standover height.
Adjust the seat height.
Whatever style of bike appeals to you, ideally you can visit an REI store and consult with one of our bike mechanics to help you sort through the fit issues involved with a bike selection.
Happily, choosing the correct frame size can be achieved without a visit to a store.
REI includes a sizing chart with each bike we feature online. The chart includes the standover height for each frame size of that particular bike. The distance between your inseam and the standover height should fall within the ranges discussed in the sections above.
For example, if you have an inseam of 30", and you're buying a mountain, urban/commuting or touring bike, you will want a standover height between 25" and 28", depending on how aggressively you ride. For a road bike, your preferred standover height would be 28" or 29". For a comfort bike, the right standover height would be in the vicinity of 27" or 28".
To measure your inseam:
Children, especially girls, tend to have long legs and short torsos. When buying a bike for children, the most important factor is that the bike should not be too large. Do not choose an exaggerated standover height hoping your child will "grow into it." A too-large bike can become unwieldy in a child's hands and lead to a loss of control as well as confidence.
Saddles, handlebar tilt, some stem angles, flat bar shifters and brake levers can all be adjusted to create a more comfortable fit. To understand where you need to fine-tune your ride, do 2 things first:
After getting acquainted with a new bike, REI encourages riders to make a return visit to a store for follow-up consultation on fit-related topics with a bike mechanic.
The following general guidance provides some self-evaluation/self-service suggestions.
Saddle position should align the knee over the forefoot/pedal spindle. Resist any inclination to adjust your saddle to achieve the proper reach to the handlebars.
Seat height: When extended in a downstroke position, does each leg retain enough bend so that it falls just short of being fully straight? If so, your seat is properly positioned.
To move your saddle up or down, loosen the seatpost binder bolt (or quick-release lever, if equipped) located at the top of your seat tube. Slide the seatpost up or down in the seat tube as needed, being careful not to raise it beyond the "minimum insertion mark" etched into its side. Retighten the binder bolt or quick-release lever before riding.
Seat tilt: REI recommends starting with the saddle parallel to the ground to get a rider acquainted with this traditional setup. Some cyclists in time may prefer a forward tilt. Others might want a backward tilt. Yet a no-tilt alignment is often the best approach. To find a tilt position that suits you, experiment with different setups. To make saddle tilt adjustments, simply loosen the saddle binder bolt (or bolts) at the top of your seatpost (directly underneath your saddle) and adjust as needed. (Note: The saddle binder bolt (or bolts) is different from the seatpost binder bolt.) Retighten the saddle bolt(s) before riding.
Seat fore/aft position: In the ideal pedaling position on any style of bike, riders will pedal with their shins angled forward just slightly. A line could be drawn from the bottom of your kneecap to the ball of your foot. If your shin is too vertical, that line would be pointing at your heel. (Review our road-bike fit video for a demonstration.) To achieve the correct shin tilt, loosen the seatpost binder bolt and slide the saddle forward or backward as needed.
Seat style: Saddle technology has flourished in recent years. A wide variety of saddle widths and styles can be purchased your individual fit and comfort preferences.
Most bikes are now equipped with fixed-positioned stems. To adjust the position of your handlebar, you may have to choose a new stem, a different handlebar or both. Step risers and other components allow stem heights, angles and lengths (plus handlebar height and width) to be modified.
By T.D. Wood
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Last updated: Tue Apr 09 11:31:41 PDT 2013
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