Bike fit systems
Bike fitters and bike fitting systems.
Bike fitting has become a thing. There are bike fitting schools turning out bike fitters, there are computer based bike fitting systems that promise to put the rider in the perfect position, and there are AI bike fitting apps that let a rider fit themselves. So how do you know what's good and what's not?
My education in bike fitting started with an injury. I compressed L4/L5 so well that I wound up in a wheelchair for a few months. That started my education about the human body. I learned about muscle groups as I remapped my own so I could ride again. My education in biodiversity was coaching the Harvard cycling team. Each September I would get 30 new riders, my task was to fit them to their bikes. Students come in all different shapes and sizes, what works for one doesn't work for the next. What I'm saying is bike fitting requires experience.
Lots of bike fits are now done by computer fitting systems. These systems have some means of measuring, and some way of using that data to make changes. I see a couple of serious problems with these as stand-alone fitting systems. First, step two of my simple fitting method is missing - teaching the rider how to get their body weight on the pedals. Second, these systems use databases from past fittings. That means the changes are made based on a standard distribution. Bike fitting should be done based on the individual, not the average.
I've been to a number of bike fitting schools, I don't think they produce bike fitters. Saying a person can go to a 4 day bike fitting school and start fitting riders is kinda like a 3 week MD program. The mistake most people make is in thinking that bike fitting is a simple subject. More often than not clients show up in my fitting stand thinking their handlebars need to come up, or maybe they need a new saddle. I then spend 2/3rds of the fitting ignoring where the handlebars are. Once they get their body weight on the pedals, where the handlebars need to be is pretty obvious. Even saying that is oversimplifying the process because bars have different bends and widths and amounts of reach and flair and where the brake hoods mounts counts for a lot too... My point here is that most bike fitters have bike fitting certifications and diplomas hanging on the wall. They aren't worth the paper they're printed on.
The question of internet bike fitting comes up often. It doesn't work, but not for the reason you might think. I've heard other bike fitters claim they can't see what they need to from video. It's not that the video quality isn't high enough - I've had clients send me 4K@120FPS videos, and I still couldn't see what I needed to. I then watched myself while I was doing a fitting. I move all over the place. I can't get the point of view I need from a fixed camera position, so I don't do video fittings. Virtual bike fitting systems use a different method, they find key landmarks on the body and create a wire frame digital representation. From there they can calculate joint angles which they base their recommendations on. This frightens me because there is so much information that's not taken into account.