Here are my notes from a lecture I attended in bike fit on November 19, 2003 at Sports Basement. The speaker was Christoper Kautz of PK Racing. [8/4/04 Update: Per an email from Angie Kautz, "Christopher always goes by his full name as he does not shorten it to Chris"].
- ...I came in late just in time to hear Christopher talk about something being 135 degrees. According to the diagram on the whiteboard, it looked like the angle between your thigh and your calf. Your knee should be slightly bent when you cycle, but not so much that you're squatting.
- When you cycle, your knees should be over the pedals (imagine a plumb line being dropped from your knee). In particular, your knee cap should be over the pedal because levers work best at 90 degrees. Push down straight into the pedal - don't push your knee over/beyond your toes
- A proper bike fit will put you in a position such that you will be in the most balanced and stable position
- Cycle with a straight back (don't hunch), shoulders relaxed and a rotated hip
- Engage your glutes for maximum power and open your abdomen for air (hunching will cause you to compress your internal organs)
- Saddles
- If you've tried a bunch of saddles, and the only way you feel comfortable is to tilt it, be careful - this is sometimes indicative of another fit problem. In other words, you may be tilting your saddle to compensate for another issue.
- Your saddle should be more or less level, tilted at most 1 or 2 degrees
- If the nose of your saddle points down, you'll slide down/off
- If your saddle tips back, your pelvis will pivot and your back will be rounded
- Handlebar height
- The height of your handlebars depend on your trunk strength, flexibility and goals
- Many riders are under the misconception that they need to lower their handlebars for maximum speed. However, if they do not have the torso strength or hamstring flexibility to maintain proper form, they'll end up contorting their body and will end up riding slower.
- Just because you raise the bars up, doesn't mean that you're necessarily bringing your body higher. In fact, your body will probably remain at the same height, but you'll be able to ride with a straight back --> better posture --> increased comfort.
- One of the key measurements for determining handlebar height is the range of motion of the pelvis relative to femur. This is usually measured by laying on your back and seeing how high you can raise your legs.
- Steer from your body, not your hands
- Maintain a slight bend in the elbows since they will act like shock absorbers.
- Ride with a neutral spine
- Cycling shoes
- Your street shoe size may have no correlation with your cycling shoe size!
- Make sure that you take 3 measurements for your cycling shoes: length, width and arch length (distance between back of foot to ball of foot). The third measurement is probably the most important.
- If you buy cycling shoes based primarily on the length of your foot, they'll probably be too small. There is supposed to be more wiggle room in the toes than regular shoes
- The cleat is supposed to be affixed just ahead of the ball of the foot (2nd metatarsal)
- Spenco insoles are recommended to disperse force
- If you have flat feet, orthodics may help
- Clipless pedals/cycling
- The best biomechanics is to point your toes forward. Your hips need to be flexible
- [8/4/04 Update] Be wary of Speedplay clipless pedals. Certain models provide limited stability and can cause tendonitis of knees. Some cyclists like them because they provide more float, but that's because there's probably something wrong with their bike fit &/or posture that requires excessive float in their pedals. This is not to say that they should always be avoided (I saw that Christopher Kautz himself has/uses a pair when I had my bike fit done by him... although I can't remember the model), but like any other piece of equipment, understand the pros and cons. For newer cyclists, I personally recommend dual entry SPDs
- Triathlon bikes
- Saddle height for triathlon bikes 135 (down) 3-5mm [Note: This was in my notes but I have no idea what this means]. But the gist of this discussion is that triathlon bikes are supposed to take the load of your hamstring to make it easier for you to run later on
- Road bikes usually have 60% of the weight distribution in the back. The saddles for tri bikes are usually further forward than road bikes.
- Your tri bike will probably be a couple of frame sizes smaller than your road bike
- Tri bike geometries are more aggressive, harder to ride, and bad for group riding (which is okay for triathlons because most of them don't allow drafting)
- If you have a tri bike, you should spend one day a week riding it (versus your road bike). Some people don't ride their tri bike until race day as though it has special magical powers which they're afraid will be used up through regular riding. This is a big mistake! Tri bikes are more difficult to ride than road bikes, so make sure you get enough practice to ride it comfortably.
- A tri bike starts to make sense if you can cycle at least 18 mph. Most people think that you should get a tri bike for longer races (like Ironmen), but they're probably be more useful for shorter races. This is because you'll be cycling slower in long distance races... possibly <18 mph.
- Aerobars
- With aerobars, your weight is supported by your humerous & skeletal structure
- As you bring your arms closer together (narrower than your shoulders), drag will decrease, but beyond a certain point, drag will start increasing again. It's best to air on the side of getting wider aerobars
- Aerobars should be flat or tilted slightly up for comfort. Your arms should not be sliding off.
- You should be able to rest and dangle your arms, and not "hang onto" your bars to stay on
- The tip of the aerobars should be a couple of inches beyond the hood, not so far forward that you're diving into the bars
- In case you're wondering, aerobars are not used in the Tour de France because they're not allowed (except for time trials). The one year aerobars were allowed there were too many crashes
- Wheels
- When cycling on flat road, you're primarily overcoming wind resistance so aerodynamics is important. Your body is 80% drag!
- 650c wheels will create less wind resistance, and your toe will be less likely to hit the front wheel
- If you are 5'10" or over, get 700c wheels
- If you can choose either 650c or 700c, go with whatever you currently have, &/or what other people in your household use (so you can bum components off them)
- Flexibility is separate from stability
- You will be a much stronger cyclist if you have strong core muscles. Christopher recounted a story where one of his triathlon friends was awesome on a CompuTrainer, but couldn't last five minutes on rollers. After this same friend spent time strengthening his core muscles and practising on rollers, he established all sorts of PB (personal bests) that year.
- Intercostal flexibility is important for cycling. Doing back bends over a stability ball is helpful
- Fixed gear bicycles are only good for track, a very specific application
- Climbing posture: sit back, open abdomen
- Places for good bike fits: himself (!), City Cycle in San Francisco, Cycle Sports in Oakland.
