Bike won't shift into 7th gear

[Das Chicken]

Hi all, i have a specialized rockhopper (7 rear speeds) with a 48cc ht and the awesome SBP shift kit. Well, i noticed the massive amount of grime building up on the guide sprockets (the plastic ones), and that they didn't spin very well either, so i decided to take the rear shifter (Shimano STX) apart and clean it. So i did. I never knew how painstakingly long (and painful) putting a derailleur back together is, but i got it done anyway. So i got it all together and tested it out: The gear selector was completely off. Adjusted that so now its accurate, all good up until 6th gear. 1-5 work fine, but when i put the selector in 6, it doesn't shift, and the selector suddenly acquires a large amount of freeplay. When i put the selector in 7 however, it goes into 6th gear. I have also noticed that the sprockets are not aligned. is this a problem?

Adjustments i have tried:
1. Pulling the derailleur cable taut then re-tightening the nut that holds it down
2. Adjusting the black knob that the wire goes through on the derailleur
3. Adjusting the black tube thingy coming out of the shift selector (on the handlebar)
4. Adjusting the two screws on the back of the derailleur

Any suggestions?

 

[2door]

Derailers (English spelling) can be a chore to adjust if you're not familiar with them. The little adjustments it requires are small and critical. However your problem sounds like possibly the cable needs to be just a little tighter.

How far did you disassemble the 'derailer'? Did you change the position of either of the adjustment screws? I'd check Sheldon Brown's website for help. There are some great tutorials on shifter adjustments. http://www.sheldonbrown.com/derailer-adjustment.html


Tom

 

[Das Chicken]

Derailers (English spelling) can be a chore to adjust if you're not familiar with them. The little adjustments it requires are small and critical. However your problem sounds like possibly the cable needs to be just a little tighter.

How far did you disassemble the 'derailer'? Did you change the position of either of the adjustment screws? I'd check Sheldon Brown's website for help. There are some great tutorials on shifter adjustments. http://www.sheldonbrown.com/derailer-adjustment.html


Tom

As far as dissassembly, i just took off the screw holding the derailer on, removed the derailer from the bike (as far as the cable would allow at least.), and separated the guide sprockets from the derailer. Regarding the adjustment screws, i tweaked both of them, but put them back to what i remembered their position was after they didn't change anything.

 

[timboellner]

It sounds like you need to adjust the high limit stop on the rear derailer. It's one of the 2 small screws on the derailer. One is labelled "L" , the other is labelled "H".Often times hard to read so look carefully.

It limits the travel of the derailer.

If it's too tight it stops the derailer from going down all the way to the smallest rear sprocket.

If it's too loose it will overshoot the bottom sprocket and wedge the chain between the sprocket and frame and that's where you can do serious damage to you and your bike., particularly with the shift kit while you are hauling butt under power.

It will munch the chain and rip your derailer to shreds. I know, I've been using a shift kit for almost 4 years now.

Another possibility is that you have bent the cage on your derailer. If you pried it apart to remove the 2 idler wheels you have more than likely ruined it. If you ever hit the curb, or laid the bike over onto the derailer it could also be bent. These things are sensitive and require careful and knowledgeable adjustment to operate correctly .

As Tom said previously, PLEASE, for your own safety read the link to Sheldon Browns site on adjusting the rear derailer. If you can't get it right, any local bike shop can do it for you. It takes about 15 minutes once you get good at it.

Get it right and test it by riding around and running through the gears many times before you fire it up. It's critical that it is indexed correctly and both high and low limit stops are on the money when you use the shift kit.

Good luck and have fun but be sure it's right before you go out riding....

TiM

 

[Das Chicken]

Finally got it working! Thanks for the help.