Healthy Living – Bike Fit Basics

Posted on: July 13, 2009 | ltpetersen | Comments Off | Print Article | Rate Post:

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Brought to you by Lidia T. Petersen D.C., Progressive Chiropractic.

Whether you ride on the bike path along Seward Highway, along the waterfront down Ballaine, or on the trails at Lost Lake, it’s  important  to pay close attention  to how your bicycle fits your body. A properly fitted bike will  allow  you  to  ride  comfortably  and  safely,  avoid injury, and produce more power, so you go faster with the same or less effort.

In general, when fitting a bicycle, there are five basic components to consider:

1. Frame size
2. Saddle (seat) height
3. Saddle position
4. Saddle tilt
5. Handlebar position

Frame Size
Frame size is perhaps the most important of all meas-
urements because once you purchase the bike, there are very few—if any—minor adjustments that can affect the overall frame.

Frame size is not necessarily dependent on your height; rather, it is more a matter of leg length. Simply, the frame should be easily straddled  with  both  feet flat on the ground, and with perhaps an inch or two of clearance.

• For a road or hybrid bike, you should have an inch or two of clearance between your crotch and the top tube.
• For a mountain bike, clearance should be about four inches—especially if you plan to ride in rugged terrain where an unplanned dismount is likely.

Note that frame sizes come in inches or centimeters, depending on the manufacturer. Also, a 21-inch frame from one company may fit very differently from the same size made by another manufacturer. Last, frame size is not the same as wheel size, which is commonly used in sizing kids’ bikes.

Saddle Height
A saddle (seat) set too high or too low can cause pain
and lead to injuries of the back and knees, and it will also affect  the efficiency  of each pedal stroke.  As a starting point, set the saddle height so that your knee is slightly bent when the pedal is at its lowest position and the ball of your foot is on the pedal. It is recommended to make adjustments in very small increments and, if applicable, to wear your cycling shoes during the adjustment process.

Saddle Position
To check the saddle position, sit on your bicycle—using
a friend  or  a stationary  object  to  keep yourself bal- anced—and rotate your pedals until they are horizontal (at the 3 o’clock and 9 o’clock positions). If your saddle is  positioned  properly,  your  forward  knee should  be directly over the respective pedal axle (with the ball of your foot on the pedal). For precise measurement, use a plumb-bob to help you visualize the alignment. If adjust- ments are needed, loosen the seat post and slide the seat  saddle  forward  or  backward,  keeping  the  seat level.

Saddle Tilt and Design
Generally speaking, your saddle should be level. Check
this adjustment by using a carpenter’s level balanced on the saddle while the bike is on level ground. If your sad- dle tips too much in either direction, pressure will be placed on your arms, shoulders, and lower back.

Saddle selection  is a matter  of  personal preference. Saddles come in gender-specific, comfort, and performance models. For example, women-specific saddles are wider at the back, have a shorter nose and usually have a soft  or cut-out  section  in the middle. Men’s saddles may also have cut-outs. When selecting a saddle, try several to find one that fits you well.

In addition to proper bike fit, there are many accessories that will help make your ride more comfortable, such as padded gloves, shorts, and even gel seat cushions.

Handlebar  Position  and Distance
Handlebar  setup  is  a  matter  of  personal  preference
because it will affect shoulder, neck, and back comfort. Generally, handlebars are positioned higher for comfort (a more upright riding position) and lower for improved aerodynamics.

Always Wear  a Helmet!

A bicycle crash can happen at any time; however, according to the National Highway Safety Traffic Administration, a properly fitted bicycle helmet reduces the risk of head injury by as much as
85 percent and the risk of brain injury by as much as
88 percent.  The following are tips to help ensure the correct helmet fit:

• The helmet should be level on the head, and it must cover the forehead.
• The Y of the side straps should meet just below the ear.
• The chin strap should be snug against the chin so that when you open the mouth very wide, the helmet pulls down a little.
• Put your palm on the front of the helmet, and push up and back. If it moves more than an inch, more fit- ting is required.
• Shake your head around. If the helmet dislodges, work on the strap adjustments.
• Do not wear a hat under the helmet.
• All helmets sold in bike shops must be approved by the U.S. Consumer Product Safety Commission (CPSC) and should carry a CPSC sticker.

Consult  a Professional
The above suggestions are general guidelines only. A quality bike shop should make the necessary adjust- ments for you or offer to help you fine-tune the fit of your bike, which is crucial to reduce wear and tear on the body, as well as minimize injuries. If there isn’t a bike pro at the shop you’re using, find one at another shop.

Courtesy of Progressive Chiropractic, 11694 Seward Highway #C.  907-224-8680

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