MTB rear derailleur shifting problem



J

J.M. Rudder

Guest
Hi,

I have a mountain bike which shifts gear smoothly, but the rear derailleur
drops the chain back down to the small cog from all other cogs unless I keep
the shifter in place with my thumb, an obvious inconvenience. I can remove
it from its handlebar mount, but the mechanism itself appears to be
contained, un-dismantlable.

Josh
Ithaca, NY
 
S

Sheldon Brown

Guest
J.M. Rudder wrote:

> I have a mountain bike which shifts gear smoothly, but the rear derailleur
> drops the chain back down to the small cog from all other cogs unless I keep
> the shifter in place with my thumb, an obvious inconvenience. I can remove
> it from its handlebar mount, but the mechanism itself appears to be
> contained, un-dismantlable.


If it's an old-style friction type shifter (doesn't click into gear) the
should be a friction regulating screw rignt in the middle of the pivot
where the lever turns. Tighten this screw until the friction is
sufficient to keep it in position. If you make it too tight, it will be
hard to move the shift lever. The screw might require a screwdriver, or
it might have a little "D" handle on it so you can turn it without tools.

If it's a modern indexed shifter, it's probalby not fixable, and you'll
need to buy a new shift lever.

Sheldon "Insufficient Data" Brown
+-----------------------------------------------------+
| Life is the art of drawing sufficient conclusions |
| from insufficient premises. --Samuel Butler |
+-----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
 

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