P
Peter Clinch
Guest
Pyromancer wrote:
> Speaking of epicyclic gearboxen, does it do any harm if you forget to
> stop peddaling when you change, or does it just not change till you
> take the load off?
It varies with how much pressure you have on them. Lots of pressure,
nothing happens until it's released, a little pressure and it will often
change okay anyway, somewhere in between it will come out of the first
gear but not really get into the next and leave you flailing in neutral,
which is a bit of a pain at times but usually a brief back-pedal will
sort things. Generally I just ease off the pressure on the SRAM 3 on my
Brom and that's fine. Stopped at lights a little back pedal often
helps, and is usually necessary to switch more than 1 gear.
The Rohloff has a unique push-pull twin cable, I think partly to allow
more positive changes that don't suffer that "spinning in neutral"
effect. It's internally a 7 speed with a step down so all the gears can
be used twice and there can be a Gotcha changing from 7-8 under load,
where you come out of the step down as well as changing the main gear
back to the lowest so it's mechanically far more complex than the other
changes. To prevent you getting in a "neutral" with no resistance it's
been deliberately fettled to go from 7-14 if there's too much load to
get properly into 8 which can be disconcerting, but not as disconcerting
as going from 7 to [undefined] with no resistance!
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 protected] http://www.dundee.ac.uk/~pjclinch/
> Speaking of epicyclic gearboxen, does it do any harm if you forget to
> stop peddaling when you change, or does it just not change till you
> take the load off?
It varies with how much pressure you have on them. Lots of pressure,
nothing happens until it's released, a little pressure and it will often
change okay anyway, somewhere in between it will come out of the first
gear but not really get into the next and leave you flailing in neutral,
which is a bit of a pain at times but usually a brief back-pedal will
sort things. Generally I just ease off the pressure on the SRAM 3 on my
Brom and that's fine. Stopped at lights a little back pedal often
helps, and is usually necessary to switch more than 1 gear.
The Rohloff has a unique push-pull twin cable, I think partly to allow
more positive changes that don't suffer that "spinning in neutral"
effect. It's internally a 7 speed with a step down so all the gears can
be used twice and there can be a Gotcha changing from 7-8 under load,
where you come out of the step down as well as changing the main gear
back to the lowest so it's mechanically far more complex than the other
changes. To prevent you getting in a "neutral" with no resistance it's
been deliberately fettled to go from 7-14 if there's too much load to
get properly into 8 which can be disconcerting, but not as disconcerting
as going from 7 to [undefined] with no resistance!
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 protected] http://www.dundee.ac.uk/~pjclinch/