Hmmm...
I wonder if this is part of the reason why Teledyne Titan frames frequently break the rear derailleur hanger or vertical dropout... too thin a metal reinforcement dropout and a mis-calculation of drive force that causes pre-mature metal fatigue?
Thanks, for the explanation!
Regards, Steve Neago
Cincinnati, OH
> 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