Shifting help needed

rflook

Hoping someone can help me with a very annoying problem. A few months ago I had a rather comical crash at slow speed which damaged my rear derailleur and front shifter connected to the same derailleur. The shifter still shifts but is rather stiff at the far end of the lowest gear.

I replaced the rear derailleur but have been having some problems shifting. The shifter still clicks as expected but I am damned if I can make the rear derailleur shift properly. I can get the gears into the highest and lowest sprockets no problems, but getting back out of them is an issue. If I get myself into a situation where I can get into and out of the largest sprocket smoothly to the next one down, then getting out of the smallest sprocket to the second smallest sprocket is a problem. If I get myself into a situation where I can get into and out of the smallest and second smallest sprocket perfectly, then moving into the second largest sprocket from the largest is a problem (it does nothing and another gear changes makes it jump over the second largest sprocket)

No matter how much playing around the with the barrel adjuster I do it either jumps around at the top or bottom end of the sprockets. The middle gears seem absolutely fine. I am certain that the limits have been set correctly.

Can anyone give me any suggestions - would the fact that the shifter is damaged a bit be a possible cause?

chris_bass

could be a bent mech hanger?

did you change the gear cable when you changed the mech? could be a kink in the cable or sticky cable housing.

Sirius631

It could be something as simple as damage to the cable outer between the frame and the derailleur, or a kink in the cable itself. Anything which introduces friction into the movement of the cable is a doozie for diagnosing unreliable shifting.

Rightarmbad

Just check that you replaced the rear derailleur with a unit with the correct cable pull.
9 and ten road are not compatible.

rflook

OK so, got myself a new cable as the old one was a bit frayed in places, but that doesn't seem to have done it. Rear derailleur is a nine speed - I have 8 speed shifters (I checked online and at local shop and this seemed ok).

After playing around with the bike a little more, I can give a little more detail. Shifting into the lowest gear (biggest sprocket) is really tough, you have to squeeze the shifters a lot for the change to happen. Once you have shifted into the biggest sprocket, a single shift (to a smaller sprocket) does nothing. All clicks thereafter drop down a gear until the third to smallest sprocket where one more shift jumps over the second smallest sprockets and straight into the highest gear (smallest sprocket). Shifting into larger sprockets seems to be ok, but dropping down into smaller ones seems to be where the problems occur.

penguin_of_death

Sounds like a bent mech hanger

rflook

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19674935#p19674935]Penguin of Death[/url] wrote:

Sounds like a bent mech hanger

Arse - I fear you are probably right. A trip to the LBS is coming up I think

Rightarmbad

You have the wrong derailleur.

rflook

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19675280#p19675280]Rightarmbad[/url] wrote:

You have the wrong derailleur.

I don't believe this is a problem. A quick search of numerous forums about using an 8 speed shifter with a 9 speed derailleur seems to show that there is no problem with this as the cable pull ratio is the same for 8/8/9 derailleurs. Since the cassette is an 8 speed then all should be good

jermas

The derailleur is definitely correct.
If it isn't a bent hanger, then check the actual mounting of the derailleur to the hanger. Make sure the rear B screw is sitting in the correct position (behind lug) and not being crushed by the hanger. Also check that the cable is attached to the clamp bolt on the derailleur correctly-in a straight line.