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-   -   Derailleur top pulley is not aligning (https://www.bikeforums.net/general-cycling-discussion/1225028-derailleur-top-pulley-not-aligning.html)

alij2018 03-04-21 01:12 AM

Derailleur top pulley is not aligning
 
Hi, I just installed a new brand Deore cassette and rear derailleur. I have noticed that the top pulley is not aligned to the the small sprocket. Thus, this is moving the chain to the second sprocket automatically. In fact, the top pulley is fully aligned with the second sprocket at start.

So, I counter-clockwised the H screw until I reached the limit, where the screw is coming off. I dod not notice the pulley moves to the right to be under the small sprocket.

I left it and continued to adjust the speed. I adjusted the L screw too and successfully aligned the top pulley it under the biggest sprocket.

I left the B screw alone as it does not seem it needs adjustment.

However, my problem for the small sprocket is unsolved. The top pulley is still not aligning under the small sprocket so that my chain can start on the first sprocket.

My derailleur hanger is not bent.

How to solve this?

base2 03-04-21 01:33 AM

It sounds like with what you have done, the shift cable is now holding the derailleur off the limit screw. This is a common mistake. You probably installed the cable before setting the limits.

You need to relax the tension on the shift cable to allow the derailleur to move further to the small cog direction. Do this by disconnecting the cable. Move the derailleur by hand, get down low, directly behind the cassette eye ball how the jockey wheel lines up under the biggest & smallest cogs & set the high/low screws accordingly...setting the derailleur maybe the tiniest fraction outboard on the smallest cog because the upper jockey wheel intentionally has some play engineered into it..

Then hook up the cable, cycle through the gears & set the cog to cog alignment with the cable tension. Then switch to the other front chain ring & set the cog to cog alignment with the cable tension again. This may be an iterative process, especially if a derailleur is particularly old & worn.

You should be good to go. But, if there's ever any doubt, you can always get down low & take a look at how things line up & adjust the cable tension accordingly. At this point, with the limits set, there is no risk of immediate catastrophic harm.

It's not uncommon to require another half a turn or so more cable tension to regain good clean shifts as the system settles into itself after a few rides.

Good luck! :)

alij2018 03-04-21 03:08 AM


Originally Posted by base2 (Post 21951353)
It sounds like with what you have done, the shift cable is now holding the derailleur off the limit screw. This is a common mistake. You probably installed the cable before setting the limits.

You need to relax the tension on the shift cable to allow the derailleur to move further to the small cog direction. Do this by disconnecting the cable. Move the derailleur by hand, get down low, directly behind the cassette eye ball how the jockey wheel lines up under the biggest & smallest cogs & set the high/low screws accordingly...setting the derailleur maybe the tiniest fraction outboard on the smallest cog because the upper jockey wheel intentionally has some play engineered into it..

Then hook up the cable, cycle through the gears & set the cog to cog alignment with the cable tension. Then switch to the other front chain ring & set the cog to cog alignment with the cable tension again. This may be an iterative process, especially if a derailleur is particularly old & worn.

You should be good to go. But, if there's ever any doubt, you can always get down low & take a look at how things line up & adjust the cable tension accordingly. At this point, with the limits set, there is no risk of immediate catastrophic harm.

It's not uncommon to require another half a turn or so more cable tension to regain good clean shifts as the system settles into itself after a few rides.

Good luck! :)

YOU ARE DAMN RIGHT. I adjusted cable first then adjusted rear derailleur. I have installed rear derailleur and adjusted tension several time in my life and it is the first time I have done this mistake lol. I still don't know why I did that.

Now it is all good. Thank you very much for helping.

base2 03-04-21 03:14 AM


Originally Posted by alij2018 (Post 21951390)
YOU ARE DAMN RIGHT. I adjusted cable first then adjusted rear derailleur. I have installed rear derailleur and adjusted tension several time in my life and it is the first time I have done this mistake lol. I still don't know why I did that.

Now it is all good. Thank you very much for helping.

No worries! Glad I could help 😎 :thumb:


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