Rear shifting problem

[Wesley Cole]

I'm trying to help a friend who has an MB-2 mt bike (sorry, I don't know the year) with a Suntour
rear derailer and indexed shifting. She complaints that when climbing, she has to continue to apply
force to the rear thumb shifter in order to prevent the bike from shifting to the next smaller rear
sprocket. She has been given a new Shimano rear thumb shifter and I have offered to help her install
it, but before we do, does anyone have an idea of what else might be causing the problem?

If we do end up needing to replace the rear shifter, will a Shimano rear shifter index properly to
work with a Suntour rear derailer? Sorry if I'm not giving you enough information (neither she nor
the bike is here), but I can find out more if need be.

Sheldon, any help?

Thanks, Wes

 

[Chris Zacho "Th]

Look on the top of the shifter, there should be a "D" ring. Lift it and screw clockwise. It sounds
like the retention has gotten loose.

If that doesn't work, then something's brobably broke. Since Shimano cmponents aren't generally
"user serviceable (one of the advantages of Campagnolo), you will have to replace the shift unit.

May you have the wind at your back. And a really low gear for the hills! Chris

Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner

 

[James Cassatt]

I had the same problem and took it to my LBS and told the guy to fix
it. He checked my chain and said it was worn (true). He replaced the chain cleaned up the drive
train and said it would work fine, but might skoip a bit and I might have to replace the
cluster. Took it home and it skipped a lot. Replaced the cluster and it still skipped. Turned
out the middle chain ring was badly worn. Replaced the middle chain ring and the skipping
stopped, but the shifting problem was still there.

The fix:

When you move to larger gears, you are pulling the derailleur. When you go down to the smaller gears
you depend on a spring to pull the derailleur down. If there is anything that interfers with that
movement you will have trouble. The main culprit seems to be dirty cable housings. My solution was
to take the cable off pull the housings off the bike and squirt some paint thinner through them with
a syringe. Then I put the whole thing back together with some thin grease on the cables.

Result, it shifts like brand new.

[email protected] (Chris Zacho "The Wheelman") wrote in message
news:<[email protected]>...
> Look on the top of the shifter, there should be a "D" ring. Lift it and screw clockwise. It sounds
> like the retention has gotten loose.
>
> If that doesn't work, then something's brobably broke. Since Shimano cmponents aren't generally
> "user serviceable (one of the advantages of Campagnolo), you will have to replace the shift unit.
>
> May you have the wind at your back. And a really low gear for the hills! Chris
>
> Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner

 

[Phil Brown]

>I'm trying to help a friend who has an MB-2 mt bike (sorry, I don't know the year) with a Suntour
>rear derailer and indexed shifting. She complaints that when climbing, she has to continue to apply
>force to the rear thumb shifter in order to prevent the bike from shifting to the next smaller rear
>sprocket. She has been given a new Shimano rear thumb shifter and I have offered to help her
>install it, but before we do, does anyone have an idea of what else might be causing the problem?
>
>If we do end up needing to replace the rear shifter, will a Shimano rear shifter index properly to
>work with a Suntour rear derailer? Sorry if I'm not giving you enough information (neither she nor
>the bike is here), but I can find out more if need be.

You just need a little adjustment. Thisten the D ring ion the shifter a bit or unscrew the RD
adjuster a turn or so you'll be fine. The Shimano shifters will not work with your Suntour
derailleurs. If you're determined to replace them (don't know why) I have a pair. Phil Brown