Drivetrain Parts Compatibility Check
04-03-23, 08:32 PM
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Drivetrain Parts Compatibility Check
Microshift 9 speed Shimano compatible shifters (new)
9 speed KMC chain (new)
9 speed SunRace 11-40t cassette (new)
11 speed Shimano RD-M800-SGS derailleur (used but was working fine with 11 speed Shimano 11-40t cassette yesterday)
By the time I have adjusted the cable tension to get me into the middle of the cassette it is already too tight to drop down to the 11t. I was working under the impression that the 11 speed derailleur would be pulling across the same total distance with 9, 10 or 11 speed cassette.
9 speed KMC chain (new)
9 speed SunRace 11-40t cassette (new)
11 speed Shimano RD-M800-SGS derailleur (used but was working fine with 11 speed Shimano 11-40t cassette yesterday)
By the time I have adjusted the cable tension to get me into the middle of the cassette it is already too tight to drop down to the 11t. I was working under the impression that the 11 speed derailleur would be pulling across the same total distance with 9, 10 or 11 speed cassette.
04-03-23, 08:43 PM
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Shmano 11 speed road or 10/11 speed moutain don't work with the old 6/7/8/9/10 road or 6-9 mountain derailleurs.
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04-03-23, 10:30 PM
#3
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The 9-speed shifter uses a different pull ratio than your Deore derailleur. Your safest bet is to use something that was designed during the 9-speed era like this.
https://www.rei.com/product/798943/s...B&gclsrc=aw.ds
https://www.rei.com/product/798943/s...B&gclsrc=aw.ds
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04-04-23, 04:32 AM
#4
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OP: @Kontact and @Joe Remi are correct. The shifters and RD you are using have different actuation ratios and are incompatible.
Background: except for very early Dura Ace, Shimano used a 1.7:1 actuation ratio for all of their SIS derailleurs. That changed at 10-speed for Shimano mountain (1.2:1), and changed again for Shimano mountain 11-speed (1.1:1). Shimano road followed suit at 11-speed, changing to an actuation ratio of 1.4:1 (the latest Tiagra 4700 also adopted this 11-speed road actuation ratio, and I understand 10-speed GRX did as well).
This is discussed in some detail at the following (and other) credible online source(s):
https://bike.bikegremlin.com/1278/bi...compatibility/
Bottom line: the combo you have won't work. You need either (1) a different RD that's compatible with Shimano's 1.7:1 actuation ratio, or (2) or some type of actuation ratio-modifying pulley assembly (jTek Shiftmate or equivalent, assuming you can find one designed for that combo). A new RD would IMO be simpler and might not be that much more expensive; the RD Kontact suggested as a replacement is presently probably even cheaper.
Background: except for very early Dura Ace, Shimano used a 1.7:1 actuation ratio for all of their SIS derailleurs. That changed at 10-speed for Shimano mountain (1.2:1), and changed again for Shimano mountain 11-speed (1.1:1). Shimano road followed suit at 11-speed, changing to an actuation ratio of 1.4:1 (the latest Tiagra 4700 also adopted this 11-speed road actuation ratio, and I understand 10-speed GRX did as well).
This is discussed in some detail at the following (and other) credible online source(s):
https://bike.bikegremlin.com/1278/bi...compatibility/
Bottom line: the combo you have won't work. You need either (1) a different RD that's compatible with Shimano's 1.7:1 actuation ratio, or (2) or some type of actuation ratio-modifying pulley assembly (jTek Shiftmate or equivalent, assuming you can find one designed for that combo). A new RD would IMO be simpler and might not be that much more expensive; the RD Kontact suggested as a replacement is presently probably even cheaper.
Last edited by Hondo6; 04-04-23 at 04:41 AM.
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04-04-23, 08:20 AM
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Here's another chart that lists the pull ratio of many derailleurs that support the info from all the above posts. First thing you need to check is if the derailleur has a 1.7 pull ratio for your listed setup as it won't work with any other ratio. Bicycle Cassettes & Drivetrains - Google Sheets
04-04-23, 10:15 AM
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Thank you all for the good information. I ordered out the RD that Joe Remi mentioned.
04-04-23, 04:40 PM
#7
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Uh oh, I forgot something. That derailleur is only rated to 34t (maybe 36) and you're running an 11-40 cassette. You might get lucky reaching the big cog or you might not.
Last edited by Joe Remi; 04-04-23 at 04:43 PM.
04-04-23, 05:36 PM
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I was aware of the limitations of that derailleur when I ordered it. Despite my thrashing with this lash up, I have in the past had good luck with pushing Shimano derailleurs beyond there stated capacities. If it doesn't work straight out of the gate I suspect it will work with a longer B screw or, if need be, a hanger extender.
Thanks for the follow up.
Thanks for the follow up.
