Hello,

I have a 10 speed Shimano 105 shifter, SL-5700.
I have a Shimano Acera rear mech, RD-M3000, which worked perfectly with it.
Due to fancier parts trickling down from other bikes I am now trying to get a Shimano XT rear mech RD-M780 to work with it and it’s not having it.
.
The limit screws are fine. With no cable in it sits perfectly in the small cog. If I connect a cable it will change all the way to up to the third biggest sprocket but no further. Pulling on the exposed cable will then get it to shift perfectly into the largest sprocket so that limit screw is fine too.
If I use the cable tension necessary to be able to select the largest sprocket by using the shifter then I cannot get the two smallest sprockets.
Basically, I get either gears 1-8 or gears 3-10 but not 1-10.
Am I missing something here?

Thanks

PS. 10 speed XT cassette 11-34 and XT 10 speed chain if that makes any difference.

SL-5700 is a 10 speed road shifter
RD-M3000 is a 9 speed MTB derailleur
RD-M780 is a 10 speed MTB derailleur

Using a 9 speed rear derailleur with a 10 speed road shifter is a functional bodge to get a wider range on a road bike.

Shimano 10s road and 10s MTB have different cable pull ratios so the 780 mech will not work.

I have the 10 speed road sti (105), 9 spd rear mtb mech (Saint) bodge “just about” working… you can’t use a 10 spd rear mtb mech, sadly. I’d like a clutch on there.

Ah.
Bottoms.
Best put the Acera back on then.
That’s a waste of an hour.
Thanks both.
.
This is now a stealth ad for an XT M780 mech… Swapsies for a 9sp XTR anyone?

Not cheap, but the Wolftooth Tanpan will probably do what you want.

Not cheap, but the Wolftooth Tanpan will probably do what you want.

The Jtek ShiftMate 6 will do it for less

https://www.sjscycles.co.uk/cables/jtek-shiftmate-6/

Thanks. But I think getting an XTR 9 speed and selling the XT 10 speed and Acera 9 speed will probably come out cost neutral and be more simple.
Or just stick with the Acera, it works🤷‍♂️

I have a 9 speed SLX mech just off my 10 speed setup, well there’s a whole setup if anyone fancies it.
cheers
Paul