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The Proper Bike Fit
 
By Ainslie MacEachran
Date: 4/26/2013
The Proper Bike Fit
 
Over the years I have spend a lot of time watching cyclists on their bikes. As a competitor I was among them, as a team director I watched a lot of races from the car where I could see from the side and behind and as a coach I've watched from every conceivable angle. One of my biggest priorities when I work with cyclists is ensuring they have a proper fit on the bike. The thousands of hours watching cyclists has allowed be to really get an eye for:
a. What a good fit looks like.
b. What a poor fit looks like AND what the consequences are.

Corporate America has spent millions of dollars on office ergonomics to ensure employee productivity and minimize their insurance costs. People that sit at a desk and use a computer get overuse injuries like cyclists do. One of the first things I do when I start working with a cyclist is make sure their bike is set up properly. I think of their bike as their office! If, as a coach, I'm going to assign them a lot of “work” I should make sure their “office” is set up right....right?

Between the cyclist and the bicycle there are three key contact points:
1. Saddle
2. Pedals
3. Handlebars

Each of these points needs to be set up so it is in harmony with the other points of contact. If you're out of position in any one, the whole equation can fall apart. Consequently, good bike position will consider all three.

The Saddle:

The primary issues I see with seats are they are either too high, too low, too far forward or too far back. Each presents its own set of issues that can influence performance and the ability to produce power. Each also carries its own set of hazards in regards to injury. A seat that is not properly positioned can create irritation and stress on the tendons of the knee, hip and ankle. There can also be issues with the musculature when you then apply power and tense the fibers.

I like to compare it to a pearl in an oyster. A pearl starts out as a grain of sand. Small and seemingly innocuous. The oyster perceives the grain of sand as an irritation and lays a layer of calcium over it. Then another layer...and another and so on until you have a big pearl. If we use your knee in this example, any irritation starts out fairly small but as you accumulate pedal revs the irritation becomes greater and greater until you're left with pain and swelling.

Proper saddle height and fore/aft position will put your hips, knees and ankles (and to a degree, low spine) in an ergonomically neutral position that will allow you to apply maximal power to the pedals over tens of thousands of revolutions with maximal efficiency and minimal stress on the tendons, ligaments and musculature.

Appropriate saddle height will be somewhere between 15 and 30 degrees of flexion at the knee. This range allows for variations like “ankling” when pedaling, leg length discrepancies and inflexibility of the Achilles tendon or calf muscle.

To pin down the fore/aft adjustment, dropping a plumb line from the base of the patella when your foot is in the forward 3 o-clock or 9 o-clock position. Ideally, the plumb should fall anywhere from the front to the rear of the pedal spindle. (Time trial bikes are a different story) This has some variations that a trained bike fitter can help you sort out.

Saddles are made to be sat on at a particular point between the front and back of the rails. If you're too heavy on the front or back, it will be very uncomfortable and create issues like hot spots or numbness. When the seat is properly placed fore/aft and set at the appropriate angle, sitting on it for extended periods will not be problematic. My biggest pet peeve is people who have their seats extremely “nose down” or “nose up”. Those two items can create problems throughout our 3 contact points AND make riding pretty unpleasant.

The Pedals:

The pedals are where you directly apply pressure to propel the bike. The pedal engages with the cleat on the base of your shoe, which has an almost infinite amount of adjustment. Problems one tends to see are cleat too far forward, too far back, or shoe too close or too far away from the crank arm. In the old days the soles of cycling shoes were made from plastic, wood or leather. Because they were not as rigid the conventional wisdom was place the cleat directly under the ball of the toe to disperse pressure as much as possible and the side-to-side adjustment required was minimal.

Now, shoes are made of highly rigid materials that do a great job of dispersing pressure throughout the sole of the shoe so we have more freedom with cleat placement. Depending on the size of your foot, cleat placement can be directly under or just behind the ball of the toe.

As far as left or right cleat placement, the common thinking is that narrower is better IF it doesn't create alignment issues. What you're ideally looking for is the leg is in a straight line down from the hip. Power is most efficiently applied in a straight line. If there are bends and turns it can diminish power and create misalignment of the knee, hip or ankle.

The Handlebars:

The bars are where you do all your steering and braking. The common placement issues I see are, again, bars too far forward or back (stem length), tilted too far down or drops are too deep or shallow.

Too high or low can have consequences for the low, mid and upper spine (including cervical vertebrae). People often describe pressure in their triceps, shoulders and hands. Additionally, if you're too high, it’s hard to get out of the wind and it can feel like your dragging a parachute down the road because your torso is catching a lot of wind.

Too far forward will give you the sensation of “reaching” for the bars, creating tension in the mid to upper spine, forearms and will adversely influence handling. Too far aft and you can have a “crunched” feeling, handling can be compromised and it can be hard to get enough oxygen since the rib cage or not optimally framed.

My belief is that when you're riding in the drops, you should have to bend your elbows to achieve a flat back. With this in mind, the depth of the drops on the bars should allow you to comfortably ride on the tops without being too high and when in the drops a 15 degree bend in the elbow would nearly achieve a flat back. This will also minimize discomfort in the neck since your not craning your head in an awkward position.

The amount of adjustment of all these elements is nearly unlimited. A trained bike fit person will take into consideration all three contact points (and potentially more!) and help you get your bike set up optimally. Keep in mind that in some cases you can experience soreness after your first ride in the new position. Your body has become familiar with operating in a particular “geometry” so rearranging the angles of your joints and musculature, even slightly, takes some getting used to. I counsel riders to give it 10 days to 2 weeks of riding and if they're experiencing abnormal discomfort, bring the bike back in so we can tweak it more.

Proper bike fit will allow you to sit on the bike for extended periods comfortably and you'll be able to generate maximal power with minimal fatigue and joint stress. In order to be able to train appropriately hard (or easy) over any duration, you'll be glad to not have to deal with irritations and injuries.


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