Anthony Marchand Bicycle Repair And Maintenance information And Tips

Adjusting Bicycle Comfort

Riding is all about comfort and efficiency. Elizabeth Quinn ( "Proper Bike Fit to Prevent Pain and Injury" ) gives a good review of bike fit and a summary video Adjusting Bicycle Comfort  is available from our YouTube channel. Here are some additional details and information (note #3 below):

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Step 1: Level and Center the Seat
  I also use a carpenter's level to adjust the seat angle. I place one end over the highest part of the right or left rear side and the other over the seat nose (i.e., in line with the rails under the seat as shown in figure 1). Most individuals will do fine when you level the seat is level with the ground. However, if you notice numbness in the hands, you may be tilted to far forward and may need to tilt the seat back just a fraction (very small amount). If you notice numbness in the groin area, the seat may be tilted to far back. The correct angle will increase bicycle comfort.

Step 2: Adjust Seat Height
  As shown in figure 2B, when the leg is fully extended, there should be a slight bend in the knee. If there is not enough bend in the knee when fully extended, there is a tendency for one's hips to rock from side to side while cycling and this may result in knee pain (figure 2A). Have a friend watch you while you cycle to advise you on these factors. Incorrect height can lead to knee pain as explained by Kirsten Gleason on bike fit. The correct height will increase bicycle efficiency.
Step 3: Fore/aft Seat Position

  Seat position (fore/aft) is another factor in bike fit. Two methods have been used, KOPS and CG (figure 3). The Performance Cycle video indicates that when the foot is in a "horizontal" position as shown in figure 4, a plumb dropped in front of the knee cap should fall directly through the center of the pedal (so called "KOPS" or knee over pedal spindle). This, however, is probably a myth as explained by John Crook of Crooks Cycle Right. Although KOPS may be a good starting point for bike fit, the key is to have the center of your body mass approximately cm in front of the bottom bracket as shown in figure 5.
  There are many ways to figure out your "Center of Gravity" (CG) on a bike, some using 2 scales, a phone book and angle measurement. The easiest is that described Keith Bontager who also gives the best description of overall bike fitting:
    "Then I determine the rider's CG (center of gravity). For convenience, I use his seated CG which I measure by placing the rider in a full crouch (with his rear end) against the wall (in his socks without his shoes on) and have him back on his feet a bit at a time until he is on the verge of toppling over. Since a human being always balances on his feet. I know his CG will be right over the balls of his feet at the moment he topples over. I measure this distance away from the wall. This becomes the horizontal coordinates for the rider's center of gravity."
    One can also observe where the balls of his feet are in relationship to his navel. The balls of my feet are approximately 4 inches above my navel in the crouched position. This is the point (center of gravity) one desire to have lined up about cm in front of my bottom bracket. You can later try moving the seat fore or aft to get a better bike fit. Some sprinters rather be slightly forward and some recreational rides rather be slightly aft of this position. It is a mater of choice and comfort.

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Anthony Marchand bicycle repair and maintenance information and tips.

Step 4: Handle Bar Height and Reach
  Width: For optimal control and efficiency, drop handlebars should be about the same width as your shoulders. So, if the distance between the bony protrusions on top of your shoulder blades is 42 cm, that's what the width of the handlebar should be (See Jim Langley's Bike Fit)
  Height: As stated by Jim Langley on bike fit, for road riders, the difference between the height of the seat and the height of the bars should be 1 to 4 inches (even lower for racers to gain aerodynamic advantage). For the rest of us recreational riders, comfort is everything. Your back should be at about a 45 degree angle at your hips. Handle bars that are to low may cause back discomfort or straining of the back of the neck as one tries looking forward down the road. As time goes by, bike shops are making that difference between the seat height and handle bar height less and less to give a more upright position and therefore more comfort to the recreational rider.
  The idea that the handle bars should hide the view of the front hub when your hands are on the brake hoods is another myth. Once you've set the seat (see step 3, "Fore/aft Seat Position"), you're ready to set the set the stem length. For recreational riders, with a 45 degree angle at your hips, you want a slight bend in your elbows so as to absorb the road "shock" as you ride (regardless of whether you can see the front hub or not). If your arms are straight when holding on to the hoods, your stem may be to long and/or the bars to low. Racers will want a more stretched out position which is more aerodynamic, i.e., a longer and lower stem.

Step 5: Shoe Cleat Adjustment

  Start with the cleat positioned so the ball of the feet rest over the center of the pedals. If the cleat is to far forward, one may experience discomfort or pain in one's toes during a long ride. Cleats that are to far back may present discomfort in arch of the foot.
  Angular positioning varies with the individual. If you feel stress in the knee, the angle probably needs to be changed. I use my stationary bike to try out the cleat position, changing the cleat angle until I feel comfortable. Many cleat have some float to allow for the natural angling of the foot. When changing a cleat, trace around the position (I use "White Out" from the stationary store), so you can position the new cleat. See Bike Fitting Guidelines - Foot to Pedal.

These bicycle adjustments should increase you comfort, especially on longer rides and will also increase your bicycle and pedaling efficiency.

Other References:
  1. Peter Jon White's How to Fit a Bicycle
  2. How to work with your Center of Gravity
  3. REI Bike Fit
  4. Peter White Cycles
  5. Steve Hogg on Bike Fit
  6. Sports Medicine