Author Topic: Shimano 11-speed road Front Shifter compatibility with 11-speed MTB shifters?  (Read 305 times)

Hi - for my Schlitter Freestyle recumbent build, which I'm currently gathering components for, I'm intending to use 11-speed Shimano XT M8000 hydraulic brake levers, M8000  i-spec II shifters, and M8000 long cage rear derailleur (with 11-42 cassette), but up front to use a Shimano 105 R7000  front derailleur and 105 R7000 50/34 chainset (160mm). I've been reading conflicting advice, though, one whether the left XT M8000 MTB shifter will work well with the road 105 R7000 front derailleur, in particular the "trim" function. As a recumbent, the bike will have a very long chain (about 2.5 chains), so in theory the chain angle should never be that steep, which I guess may help a little and reduce the need for trim, but would I be better off using a "road" i-spec II flat bar shifter on the left for the front derailleur for better shifting/trim? e.g. SL-RS700: https://bike.shimano.com/en-EU/product/component/105-5800/SL-RS700.html or U5000: https://www.bike-components.de/en/Shimano/Metrea-SL-U5000-2-11-speed-Shifter-w-I-Spec-II-p50519/ (think the SL-RS700 shifter is Ultegra level and possibly the better one?)

NB: I want to use the  i-spec II mounting to reduce bar clutter and don't care about losing the gear indicators

Thanks
Old enough to know better, but young enough to do it anyway

IIRC the cable pulls are close but not exactly identical.  Provided  the cable pull of the shifter is more than that of the FD you will be able to set the big ring trim clicks but you will probably have only one position on the small chainring, determined by the limit screw.  IIRC there are folk running this setup out there (on DFs) so it can't be impossible per se. 

If it throws up a problem you may be able to overcome it using a shiftmate…?

I have a set of 11s road shifters and have been meaning to measure the cable pulls properly. If it helps  you I might get my finger out and actually do it sooner rather than later.

cheers

think the SL-RS700 shifter is Ultegra level and possibly the better one?

The RS700 has no Ultegra markings on it and there's nothing obviously special about it to differentiate it from any other flat bar shifter. It's not I-spec either.

The compatibility chart says the U5000 will work fine with a 105 mech (brown means discontinued).

think the SL-RS700 shifter is Ultegra level and possibly the better one?

The RS700 has no Ultegra markings on it and there's nothing obviously special about it to differentiate it from any other flat bar shifter. It's not I-spec either.

It looks like there is an i-spec II version of the RS700 available: https://www.bike-discount.de/en/buy/shimano-sl-rs700-i-spec-ii-2-speed-flat-bar-shift-lever-left-1007307

The RS700 has a carbon shift lever (like the XTR levers), I think it's just regular composite on the U5000

The compatibility chart says the U5000 will work fine with a 105 mech (brown means discontinued).

Thanks, that chart unhelpfully doesn't seem to list the Rs700m but I suspect it's fine with an 105 R7000 FD
Old enough to know better, but young enough to do it anyway

IIRC the cable pulls are close but not exactly identical.  Provided  the cable pull of the shifter is more than that of the FD you will be able to set the big ring trim clicks but you will probably have only one position on the small chainring, determined by the limit screw.  IIRC there are folk running this setup out there (on DFs) so it can't be impossible per se. 

If it throws up a problem you may be able to overcome it using a shiftmate…?

I have a set of 11s road shifters and have been meaning to measure the cable pulls properly. If it helps  you I might get my finger out and actually do it sooner rather than later.

Might be useful, thanks!
Old enough to know better, but young enough to do it anyway

my measurements suggest that ST-5800 LH shifter pays out cable as follows;

1.0-1.1mm between top gear trim clicks
~5.0mm between left trim click on big ring and right trim click on small chainring
~1.7mm between trim clicks on small chainring

i.e. a total of ~7.8mm cable pull across the full range.

IIRC this is less than the pull associated with typical MTB front mechs, but in fairness I have not measured XT 11s shifters for their cable pull.

cheers