Jobst Brandt once wrote:
> The longitudinal dropout also was a major cause of Campagnolo axle
> failures because the jam nut is unsupported in the fore and aft or chain
> tension direction. Chain tension is about a four times greater force
> than rider weight because it has about a 2:1 ratio at the crank and is
> concentrated on one side of the axle. Those dropouts bugged me from the
> first day I worked with them. I was glad to discover vertical dropouts
> on Diamant bicycles at the 1960 Olympics. That was the end of axle
> adjusting screws for me."
Don't be silly, jobst. The jam nut could be supported on a 3rd side (instead of just topside and downside) by threading the dropout adjuster head through a metal shim. It just isn't done. You could also reverse the adjuster and have the wheel exit the dropout in the rear of the bike, like a track rear fork, allowing the jam nut and axle to be supported by a horizontal dropout. In fact, if you had the dropout adjuster on the front (right bike side), and the back (left back size), then i bet you could ride without tightening the quick releases or axle bolts.
It seems that horizontal dropouts aren't the problems; its the _design_ of today's horizontal dropouts that are a problem.
- Don Gillies
San Diego, CA