Current Projects chat and miscellany

It's indeed fascinating that my poor girlfriend was the victim of my experimentation of adjusting the bicycle and listening to her complaining (not that I did it on purpose), I also learnt that many fitting like the KOPS, handlebar in line with axles, etc. are about as useful as the BMI.

It's even more interesting when you're looking at very tall or small bicycle where the modern day geometry aren't always sufficent, Lennard Zinn's an example of trying to get the geometry right for those who's over average height;

What’s one major misconception of bicycles built for taller people, or in the construction of them?

Once you get to be an adult—at least with road bikes—basically everybody has the same length crank: 170-175mm, or even 165-180mm. With certain cranks, you can get that much range, but that’s still no kind of range relative to the difference in proportions of people. And then with wheel size, other than a few people riding 650B...smaller people can get away with smaller wheels... there’s no bigger wheels. Everyone’s got the same wheel size.

Now with mountain bikes you have a big range of wheel sizes, which is wonderful. I’m really happy about that.

One of the problems then, if you take someone as tall as me, and you’re going to fit them on a road bike with a 175mm crank, and you want to do the standard knee-over- pedal positioning, the seat has got to be way, way back over the bottom bracket in order to get the knee over the pedal. What you end up with really makes the bike terrible, in my estimation. You have a super-shallow seat angle in order to get the seat back far enough to get the rider’s knee over the pedal.

And what you end up with is the rider cantilevered way back over the rear wheel—weight distribution is awful. You have very little weight on the front wheel, and tons on the rear. It tends to wheelie the bike riding up steep climbs, and it doesn’t really have good weight distribution for handling on the descent.

And I think those bikes just generally do a disservice to tall riders and tend to discourage them from riding, because most tall bikes are too flimsy and too flexible. They just shimmy. And then with this positioning problem, the rider winds up super folded up at the hip angle because the seat is pushed so far back, and then the handlebars are not far enough forward and way too low. They’re just uncomfortable.

And that’s for a skinny tall guy! For a tall guy with a beer belly, it’s even worse! The shimmy is worse the heavier the rider gets. Those guys are the ones that really need to be riding a bike, and are the ones least comfortable and least safe on the thing.