I was biking on the Screamin’ Salmon, my fixed gear bike, and think I discovered the answer to the handlebar dilemma: why are lower handlebars more comfortable on my Bianchi and less comfortable on my fixed gear. The answer has less to do with the style of handlebars, as I mentioned previously, but the kind of bike.
You sit a lot more on a fixed gear. On a road bike, when you coast, your legs are supporting a good part of your body, and your ass is supporting the rest. Your legs are often supporting all your weight, as when you go over a bumpy stretch. Then your butt is hovering just over your seat and your hands are barely grasping the handlebars. The bike and your legs take all the bumps. This is why bikes don’t need shock absorbers.
(I have to say, shock absorbers are kind of fun, but that’s for another post. I think shock absorbers can even be dangerous inasmuch as they may make you relaxed about going over bad pavement. You can’t ignore bad pavement because some potholes in this city will eat you and your bike alive, shocks or not.)
As opposed to riding a normal free-wheel bike, you can’t really coast on a fixed gear. You can, but you have to let your legs turn with the wheel. Because of this, you don’t support yourself with your legs when you “coast” on a fixed gear. Rather than, in effect, standing, you sit on your seat and divide your weight between the seat and the handlebars. Going over bumpy pavement while still peddling is one of the skills you (by default) must learn on a fixed gear. It’s not how you normally ride a bike.
The lower the handlebars, the more weight gets shifted from your bum to your hands. That’s no problem if your legs are holding most of your weight. But if you’re not using your feet for support, low handlebars mean that too much of your weight is on your hands and arms. This hurts.
So raising the handlebars on a fixed gear means your seat takes most of the bumps on the road. And a well-padded seat I have. This also explains why more novice bikers like high handlebars. It’s better for your weight to be on your seat than on your hands. A more racing position, on the other hand, puts most of your weight on your legs, with your seat taking most of the rest and your arms, by pulling and pushing on your grips, primarily give you more peddle power.
I don’t know if all this is right, but at least I think I’ve figured it out.