S
Simon Brooke
Guest
in message <[email protected]>, emma
('[email protected]') wrote:
> I now have a very nice ladies Raleigh Clubman 531 frame and a shimano
> triple. So I have the new wheels and drops I can canibalise the dawes
> for, a new £12 ebay brooks leather saddle to go on it, but no front or
> rear mech. (lovely shiny suntour downshifters though So what mechs
> should I look for, and the bottom bracket is dead anyway - so how do I
> figure out what I need?
Excellent! OK, all deraileur mechanisms work in much the same way, and
the only significant improvement in deraileurs in the past twenty years
is the 'slant parallelogram' (in pre-slant-parallelogram deraileurs the
parallelogram pivots are at right angles to the projected line of the
wheel axle, in slant parallelogram deraileurs they are twisted off by
about 22 degrees. This is subtle but does help changing.)
Indexing mechanisms are all in the hand controls, not in the deraileur
mechanisms. Consequently if you're not worried about indexing you can
use any mechanism that will fit and will accommodate enough gear range.
Deraileurs fail in two ways: they get bent, and the pivots get sloppy.
If the pivots are sloppy the deraileur is a write off. If the mechanism
is bent it may be hard to straighten but will work fine if
straightened. If it's just cruddy and filthy it will clean up overnight
in a bath of parafin, followed by the gently application of a
toothbrush (but do remember to relubricate it afterwards). The jockey
wheels can be replaced cheaply if worn.
What all this is saying is that there is in principle no reason to pay
the price of new deraileur mechanisms. Good old ones, with a bit of a
clean and some TLC, will be very nearly as good as good new ones and a
lot better than cheap new ones. Obviously if you can afford good new
ones they are very nice.
--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; Want to know what SCO stands for?
;; http://ars.userfriendly.org/cartoons/?id=20030605
('[email protected]') wrote:
> I now have a very nice ladies Raleigh Clubman 531 frame and a shimano
> triple. So I have the new wheels and drops I can canibalise the dawes
> for, a new £12 ebay brooks leather saddle to go on it, but no front or
> rear mech. (lovely shiny suntour downshifters though So what mechs
> should I look for, and the bottom bracket is dead anyway - so how do I
> figure out what I need?
Excellent! OK, all deraileur mechanisms work in much the same way, and
the only significant improvement in deraileurs in the past twenty years
is the 'slant parallelogram' (in pre-slant-parallelogram deraileurs the
parallelogram pivots are at right angles to the projected line of the
wheel axle, in slant parallelogram deraileurs they are twisted off by
about 22 degrees. This is subtle but does help changing.)
Indexing mechanisms are all in the hand controls, not in the deraileur
mechanisms. Consequently if you're not worried about indexing you can
use any mechanism that will fit and will accommodate enough gear range.
Deraileurs fail in two ways: they get bent, and the pivots get sloppy.
If the pivots are sloppy the deraileur is a write off. If the mechanism
is bent it may be hard to straighten but will work fine if
straightened. If it's just cruddy and filthy it will clean up overnight
in a bath of parafin, followed by the gently application of a
toothbrush (but do remember to relubricate it afterwards). The jockey
wheels can be replaced cheaply if worn.
What all this is saying is that there is in principle no reason to pay
the price of new deraileur mechanisms. Good old ones, with a bit of a
clean and some TLC, will be very nearly as good as good new ones and a
lot better than cheap new ones. Obviously if you can afford good new
ones they are very nice.
--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; Want to know what SCO stands for?
;; http://ars.userfriendly.org/cartoons/?id=20030605