Drivetrain help please

bobcheese

Guys, need some help. I'm setting up my new drive train (SLX 10sp double) with SLX rear and shifters. Trying to sort the rear mech. Got the lower jockey wheel in line using limit screws but when I connect the cable and try shifting I get a problem. Basically I can shift to the lowest gear but the upper jockey wheel stops the chain moving to the upper cog. Even with the b tension screwed all the way in. So I am wondering if the chain is too long and not putting enough tension on the mech so it is in the correct place. I set the chain length as large ring - large cog + 2 links.

Any thoughts?

The Rookie

Ignore the lower jockey wheel, it's the upper's postition that counts.

Have you sized the chain as per manufacturers instructions/parktools/sheldon brown (all give the same length).

'upper cog' being which one?

bobcheese

So when I put the shifter to the lowest gear the chain should move to the largest cog on the rear cassette but the upper jockey wheel gets in the way and won't allow the shift. Like I said I think the chain length is set as large cog to large ring (not through mech) + 2 links

The Rookie

OK either you have the wrong mech (not able to accomodate the largest sprocket) or the chain is too SHORT (that will pull the mech forward and the upper jockey into the sprocket - don't ask me how I know this for sure, I just do ;-) ) or the B-screw needs winding in even more (pushing the mech back an the upper jockey down).

How stretched forward is the lower part of the mech when this happens (photo's would help).

Does this happen with the chain on both front rings or only one, if so the larger or the smaller?

Chunkers1980

Check the mech is screwed on correctly and the bump is in the correct place.

bobcheese

This

Chunkers1980 wrote:

Check the mech is screwed on correctly and the bump is in the correct place.

Thanks for the help