Jtek Shiftmate woes

[Rhythm Thief]

I'm currently running my Mercian with Campag 9 speed. Everything is Campagnolo except the rear cassette, as the rear wheel has a Shimano freehub. With this in mind I did a bit of research and found the Jtek Shiftmate, which is apparently designed to match Campagnolo shifters and derailleurs to Shimano cassettes by changing the cable pull ratio. Fabulous.
So I bought one (and they're not cheap!) and fitted it according to the instructions, including turning the pulley around. And here's the thing... The shifting was immediately much, much worse, to the point where if either extreme of the cassette worked, the middle was unusable, with the chain constantly jumping between two cogs. I've just ridden home from work, avoiding certain gears, and taken the thing off because the shifting is better without it. These things get good reviews (and it's nicely made) and I'm not new to setting indexed gears by any means, but am I doing something wrong here or has anyone else had issues with these things?

 

[ColinJ]

Maybe try the pulley the other way round and see what happens?!

 

[Rhythm Thief]

Maybe try the pulley the other way round and see what happens?!

Yeah, I suppose, although the instructions are very specific and direct you to a website where each shifter and cassette combination is matched to pulley orientation, which is why I turned it around from the way it was when it arrived. But it's so shockingly bad (and everyone else who has used them raves about them) that I'm starting to think I must have got something wrong and maybe this is it.

 

[Sharky]

Not used one myself, but there seems to be a lot of shiftmates available. Which is your model.

You might get some constructive advice from the likes of Sjs Cycles.

 

[Rhythm Thief]

Yeah, they're my next port of call. To be honest, having just ridden it uptown without the Shiftmate, it works so much better without it that I might just send it back.

 

[Ajax Bay]

Mercian with Campag 9 speed . . except the rear cassette, . . . Shimano freehub.

Not answering your OP.
I have a set of Campagnolo wheels with a 9sp (C) cassette.
I have tried them in my 9sp Shimano STIs/RD and provided you get the centre sprocket bang on, the others both up and down, are functional (but I will use the rear wheel only in extremis because it has a tub rim).
The sprocket pitch is only 0.2mm different. The way you are going (C ergos/RD and S cassette) it is 'easier: see below.
At #2 and #8 (second largest and smallest sprockets) the guide pulley is only 0.6mm out.
At both extremes (largest and smallest sprockets) the guide pulley can be restrained by the use of L and H limit screws.
https://sheldonbrown.com/drivetrain-mixing.shtml
https://sheldonbrown.com/cribsheet-spacing.html

 

[Gunk]

I used one a few years ago for a turbo trainer bike I built up in lock down with bits I already had (9 speed Chorus cassette with 9 speed Sora Brifters/mech) and it is a lot of faffing about, you can reverse the pulley to change the indexing Jtec provide a useful guide to which side to use. in the end I scrapped it and went full Campag. It is a bit of bodge.

 

[andrew_s]

The pulley has a larger diameter groove and a smaller diameter groove, with the cable feeding on one and off the other, having swapped via a hole in a part of the pulley that's remote from the action.
Reversing the pulley means changing the larger diameter cable feed from being shifter side to mech side, or vice versa.
If you manage to turn the pulley round without changing the shifter side feed on diameter, it won't work as intended.

Sorry if that's egg sucking advice.

 

[Gunk]

The pulley has a larger diameter groove and a smaller diameter groove, with the cable feeding on one and off the other, having swapped via a hole in a part of the pulley that's remote from the action.
Reversing the pulley means changing the larger diameter cable feed from being shifter side to mech side, or vice versa.
If you manage to turn the pulley round without changing the shifter side feed on diameter, it won't work as intended.

Sorry if that's egg sucking advice.

The pulley has two different size grooves in it. As the cable enters the ShiftMate's housing, the proper size pulley groove has to be aligned with the cable. It may be necessary to remove the 4mm screw and flip pulley around so either the larger or small pulley grooves are facing the correct direction for the prop- er ratio of the components you are mating.

http://www.jtekengineering.com/instructions/Jtek_Shiftmate_Instructions.pdf