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Discussion Starter · #1 ·
I just bought my Specialized Myka Expert about a month ago and for the last 2 weeks it has been shifting horribly. I took it to the LBS that i bought it from and the guy looked at it and told me nothing is wrong. But that can't be right because i have to go down 2 to actually shift down a gear and it is the same when shifting up. Then on top of this it is at times just shifting where ever the hell it likes which is annoying when going up a relatively steep hill and it decides to shift from 5th(my preferred climbing gear) to 9th. I'm not sure whats wrong and the LBS was absolutely no use. Any help that can be given would be much appreciated. Everything in the drive train is shimano too btw. Thanks in advance!
 

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aussiemegs said:
I just bought my Specialized Myka Expert about a month ago and for the last 2 weeks it has been shifting horribly. I took it to the LBS that i bought it from and the guy looked at it and told me nothing is wrong. But that can't be right because i have to go down 2 to actually shift down a gear and it is the same when shifting up. Then on top of this it is at times just shifting where ever the hell it likes which is annoying when going up a relatively steep hill and it decides to shift from 5th(my preferred climbing gear) to 9th.
The auto-shifting from 5th to 9th has me puzzled. That's quite a big jump!

Aside from that, when you need to shift twice to shift one gear, that suggests gummed up cable housing. However, your bike is relatively new. Have you ridden it through water or in muddy conditions? Have you crashed or fallen so that the bike has landed on the drive side?

Anyway, here are some things to check:

1) Dirty or gummed up cable housing. If the cable doesn't slide freely through the housing, it won't shift well.

2) Sharp bends or kinks in the rear derailleur housing. Given that your bike is new, this is a stronger possibility than #1.

3) Bent derailleur hanger. This could have happened if you fell on the drive side, or perhaps even if the bike were laid down on the ground on the drive side.

4) Poorly routed or poorly sized rear derailleur housing. If the derailleur housing is routed under the bottom bracket or in such a way that the housing can be partially pulled out of the housing stops on the frame during suspension compression, then this can be a cause for the auto-shifting that you're experiencing.

5) Frayed rear derailleur cable. A frayed cable create a lot of friction at the point of the fraying, leading to weird shifting problems.
 

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Discussion Starter · #3 ·
Ive ridden in muddy conditions once and only through a couple of puddles here and there. Thanks for the reply, I'll check all those things out today before going for a ride this afternoon. Thanks again :) if i do find any of these problems how do i fix it?
 

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aussiemegs said:
Ive ridden in muddy conditions once and only through a couple of puddles here and there. Thanks for the reply, I'll check all those things out today before going for a ride this afternoon. Thanks again :) if i do find any of these problems how do i fix it?
Dirty, gummed up, or kinked housing: Replace it. It's difficult to rehabilitate dirty housing.

Bent derailleur hanger: Bend it back to where it belongs. However, it helps to have a tool for diagnosing whether it's bent. The same tool may be used to bend the hanger to the correct location. (Park DAG-1.) You'll mostly likely need help from a shop for this job since a special tool is required.

Poorly routed or sized derailleur housing (causing ghost or auto-shifting): Replace the segment responsible with a longer piece of housing. If your housing is routed under the bottom bracket, then the piece that you'll need to replace is that segment (that goes under the BB). You can diagnose this problem by placing the bike in a stand, taking care to support the rear wheel from the bottom. Then, remove the shock and cycle the suspension through its full range of motion. Watch for any place where the cable housing catches on the frame. On my old Specialized Enduro, the housing was routed underneath the BB and the segment running under the BB would get pulled out of its stops when the suspension was compressed deeply enough. Replacing that segment with one that was about an inch longer fixed the problem.

Frayed rear derailleur cable: Replace cable. To diagnose this, shift into your lowest gear while pedaling. Then, without pedaling - get off the bike to do this - move the shift lever repeatedly to put the bike in its highest gear. Since you aren't pedaling the bike, the derailleur won't actually be moving. (If you have a rapid rise or low-normal derailleur, you'll start off shifting to the highest gear and then move the shift lever repeatedly so that the shift indicator shows the lowest gear.) This should create a lot of slack in the cable and will allow you to easily pull the housing out of its stops in order to inspect the places where the cable enters and leaves the housing. Pay particularly close attention to the section of cable going into the shifter and into the derailleur. You'll also be able to slide the housing along the cable to see how freely it slides. Each segment should slide very freely. If it doesn't, then there's a problem with either the cable or the housing. If there's no obvious fray in the cable, then the problem is most likely in the housing.
 
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