Archive for April 2011

Bike Fitting

Tuesday, April 19th, 2011

I get asked on a pretty regular basis how I go about fitting someone on a bike. Its certainly a fair enough question. Cruisin’ the Net, one can soon see that there are hundreds if not thousands of ‘expert’ bicycle fitters on this continent alone. Its easy to see why it would be so confusing for those recently coming to the sport….or even the uneducated who have been drifting around in it for a while. Super laser-assisted, intergalactic double espresso, latte equipped, endothermic equipment with capabilities only just short of being able to rid the world of all known diseases surely must do a fab job, no? Throw in the dough it seems to cost to get this all happening and you’ve gotta be the first one to the top of the Alpe.

I still have my doubts, largely because with the hundreds of folks I see in all the gear, riding bikes right out of the adverts, only one in about ten (not including real racers)  look half way good on his/her bike. That means only one in ten is going to be able to get the best out of themselves in a comfortable, efficient fashion.

How hard can this be? In our our eg0- infested western world we seem to make a big deal out of almost everything so that many that even think they have any knowledge soon become bloated on self importance, perhaps to mask their own dubious worth, then miss the point by not really having a common sense look.

All that said, let’s be simple about this. One of my favourite bits of advice is to suggest that those that want to observe what good positioning on a bike should look like, is to simply acquire a DVD of some Euro pro racing. Whilst playing the disc, take the opportunity to slow or even stop the PLAY. Observe to what extent the legs extend at the bottom of the stroke, see how relaxed the arms appear and note where the riders hips may be in relation to the bottom bracket area. Granted some of the pro riders tend to have a significant vertical drop to the bars that is not suitable for many but the long relaxed reach should remain…..just higher up. The arms are your suspension, the triceps the springs.

So that’s what I set people up to ride like. That’s the goal. To begin that little journey, I use four anatomic measurements. These are the tickets for a family of four to get into the ballpark. They are inseam, femur length, body length and arm length. Of these I feel that the relative length of the femur compared the inseam is paramount. The long or short of it is what determines where you sit in relation to the cranks, that bit of the bike that receives the energy for ahead motion. If the cranks get weak signals guess what?…you go slow(er).

The business end of the femur is the area where it attaches to the pelvis/hip zone. This is anatomic ground zero for power production. No matter how strong are the quads, if your glutes and all their little surrounding buddies can’t give full foundational support, your cranks will be short changed. If that bit of your body is too far back, too far forward or too high in relation to those cranks, the foundation is weak.

Once we’ve got the basic measurements, I can get the riders position pretty close, at least ‘on paper’ close. While we’re at least in the park, without the vital refinements we’ll never make it out of the dugout. This is where we need to see the rider actually pedaling. As you can easily imagine, riding the bicycle locked onto a training rig is not the ultimate method to observe this. The bike is not flowing underneath the rider. Any naturally occurring upper body movements that most of us have when we ride will get snubbed by the stationary position of the bike.

Whenever I can, I ride with the customer on the road. This is the best way to determine what is the natural pedaling style for the individual. Its where I can see if and what effect one leg shorter than the other is having (always set saddle height to the shorter leg…unless its really radical and then a lift should be employed). Too much tension in the arms and shoulders usually effects the steering (wobble-matic).  Some folks have a natural and unavoidable heel up style and on the road is where it can really show up ( not the greatest thing and it should be cured if excessive as it decreases the effectiveness of the hamstrings in getting a longer more powerful stroke). This is often the result of too many miles with the saddle being too high…by far the most common malaise of people’s cycling positions.

Muscle attachment points can also make something of a difference which can show up in ‘on the road’ style. For some reason God decided my quads would attach further away from the knee area than most folks of my femur length. Therefore, I need to be slightly further ahead to compromise for the reduced leverage.

So in a bit of a nutshell….that’s what I do. Not every rider is going to be a ground-pounder like Cancellara, but an awful lot more folks could be sitting on their bikes in a similar fashion.

Common sense and observation….in cycling and life.