Shimano compatibility

[tinmug]

(Disclaimer: It's been years since I last had to fix/fit anything to a bicycle, so I am basically a complete idiot)

 

Have a 2018 MTB with standard Deore shifters, front derailleur plus XT rear derailleur (2x10). Trying to fit an older generation set of XT shifters (SL-M780) for the most part seems just fine, except I am unable to get what I'd imagine to be the full range out of the front derailleur using the XT shifter (it worked fine with the Deore shifter).

 

Once adjusted to happily change between two front rings I have some rubbing on both the high and low limits (limit screws turned outside that range). Put another way: it's almost like the 'throw' of the XT shifter is a little shorter than that of the current-generation Deore shifter. Could that be?

 

Rear seems to be quite happy though. 

[PeterF]

There should be a setting at the bottom of the shifter, make sure it is set to 2x.

[tinmug]

Can confirm that I managed to get that part right. 

[DieselnDust]

Is the cable routed to the derailleurs lever (not the shifter) correctly? Some Fd models have two paths for the cable to follow to get to the pinch bolt.

[fanievb]

the FD aligned properly?

[PeterF]

Can confirm that I managed to get that part right. 

Try setting it to 3x then make sure that the shifter is shifted down as low as it can go then set it to 2x.

[tinmug]

Routing:

 

 

Aligment:

 

[tinmug]

Try setting it to 3x then make sure that the shifter is shifted down as low as it can go then set it to 2x.

 

Just checked that: I can only adjust the x2/x3 setting when in '(virtual) middle ring' or 'large ring' (if on x3). 

 

The best compromise I can currently reach is having the derailleur just able to shift from small ring to large ring and even then the inside of the derailleur still touches the chain (large ring on cassette, with limit screw effectively disabled), but then the chain still rubs on the outside of the derailleur when on smallest cassette ring. Quite literally like the XT shifter has too little movement (a fraction more movement between shifts will solve the problem). 

[PeterF]

How much slack does the cable have it should be pretty tight when the derailleur is in the low setting. Too much slack will effectively limit the throw of the derailleur.

[tinmug]

Very little slack: with any more slack it won't move the derailleur enough to shift to the larger chain ring. 

[PeterF]

Very little slack: with any more slack it won't move the derailleur enough to shift to the larger chain ring.

 

No, what I am trying to say is that there must be no slack in the cable.

[ABrooks]

Following, I have the same issue with deore 2x10 front derailleur and slx shifters. I haven't checked it yet, but I think it might be an alignement issue with the derailleur. As in say the front left is rubbing on the small chainring and the right back rubbing on the large ring.