Rich Grise said:I have an idea for a different pedal arrangement, but I want to know if
it's worth it to pursue, and it hinges on the question in the subject
line: Do typical trikes have a gearshift?
Almost always, yes, though there are plenty of possibilities /how/.
Quoted message said:10-speed bikes, of course, have the derailleurs; but if you make an
emergency stop in high gear, you have to screw around with it to get
it back to low gear so that you can get going again. Are trikes like
that?
My invention is a pedal-power transmission system that doesn't depend on
derailleurs, and you can shift from high to low without having to be
in motion.
So, if there are trikes with a gearshift that's _not_ derailleurs, I'd
like to hear about it.
Epicyclic hub gear systems are nothing new, but often have limited
range. The Rohloff Speedhub is a notable exception, and is
available as a standard option on several recumbent trikes from the
factory, and could be fitted to many others. It gives a 520%
overall gearing range, and can be changed while stood still as well
as while you're going. The catch is they have a very big price
tag, but since recumbent trikes tend not to be cheap to start with,
and tend to be ridden by folks willing to spend $$$s on cycling,
they're more common in the recumbent world than you might think.
Another way used to overcome the changing when stopped problem is
the DualDrive, which mounts a rear derailleur on a 3 speed hub
rather than use it in conjunction with a front derailleur. So
while the rear sprockets can't be changed when moved, you can still
change the hub epicyclic. Another advantage is it maintains a
smoother chainline than a front derailleur, with all the rear
sprockets easily available in each of the 3 hub-selected gears.
And another way would be a Schlumpf bottom bracket mounted over or
under drive, which is a twin speed system changed with a heel
button at the crank centre. The Mountain Drive gears you down 2.5
times, the Super Speed Drive gears you up 2.5 times, so if you're
on the "big" range you can gear down quite dramatically at standstill.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/