Shimano GRX 10-speed Rear Derailleur compability issues
09-30-19, 01:25 PM
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Shimano GRX 10-speed Rear Derailleur compability issues
Hi. I recently changed my rear derailleur to the new GRX 10-speed medium cage. I am running it with my old shifters which are 105 10-speed. Before changing the rear derailleur the shifting was working flawlessly. After changing to the new rear derailleur I am having issues with shifting in the middle of the cassette. From 6-7 cog in the rear, I have to use 2 clicks to shift once. All the other gears are shifting well. Is this a compatibility issue? I read an article claiming the following "GRX400 10-speed is compatible with current Shimano Tiagra-level 10-speed groups". Is there a difference in cable pull between 10-speed Shimano and 10-speed Tiagra causing this problem? I have changed the rear derailleur hanger and outer and inner cable without any luck.
09-30-19, 01:36 PM
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Your new derailleur requires a different cable pull from that of your older 105 10-speed brifters. It requires the newer 10-speed cable pull which is the same as 11-speed pull. 10-speed Tiagra also uses this cable pull which is why it's the recommended group.
09-30-19, 01:40 PM
#3
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Tiagra 10-speed is not compatible with earlier Shimano 10-speed (such as 105, Ultegra, etc.) components. The derailleur actuation ratio has been modified from the previous 1.67. Best I can measure, it is now roughly 1.5:1.
Tiagra 10-speed rear derailleurs are compatible with Shimano road 11-speed shifters.
Tiagra 10-speed rear derailleurs are compatible with Shimano road 11-speed shifters.
09-30-19, 03:57 PM
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Shimano did this out of necessity. Before Tiagra 4700, upgrading to 11 speed necessitated pretty much a whole new groupset, but since the introduction of 4700, someone wanting to upgrade to 11, and who knows 12 speeds need only change shifters, cassette, and chain, much cheaper. 11 speed required a whole new cable pull ratio, the previous generation 10 speed setup couldn't be stretched to 11 speed
Last edited by alcjphil; 09-30-19 at 04:36 PM.
09-30-19, 09:00 PM
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So you have two options:
1. Change the shifters to Tiagra 4700 (and only Tiagra 4700 - not 4600 or any other model)
2. Change the rear derailleur to any 8,9 or 10 spd either road or MTB- doesn't matter. Only exception is Tiagra 4700 which is essentially the same as all the 11 spd derailleurs, just heavier.
1. Change the shifters to Tiagra 4700 (and only Tiagra 4700 - not 4600 or any other model)
2. Change the rear derailleur to any 8,9 or 10 spd either road or MTB- doesn't matter. Only exception is Tiagra 4700 which is essentially the same as all the 11 spd derailleurs, just heavier.
10-03-19, 09:36 AM
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So you have two options:
1. Change the shifters to Tiagra 4700 (and only Tiagra 4700 - not 4600 or any other model)
2. Change the rear derailleur to any 8,9 or 10 spd either road or MTB- doesn't matter. Only exception is Tiagra 4700 which is essentially the same as all the 11 spd derailleurs, just heavier.
1. Change the shifters to Tiagra 4700 (and only Tiagra 4700 - not 4600 or any other model)
2. Change the rear derailleur to any 8,9 or 10 spd either road or MTB- doesn't matter. Only exception is Tiagra 4700 which is essentially the same as all the 11 spd derailleurs, just heavier.
EDIT: Looks like the 10 speed GRX uses the 11 speed shimano pull ratio like Tiagra 4700. See below
Last edited by santacruzbob; 10-06-19 at 07:00 PM. Reason: inaccurate
10-03-19, 01:51 PM
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For future reference, Shimano has on their website a compatibility chart so you can figure out exactly what works with what.
https://productinfo.shimano.com/#/co...453&acid=C-453
It clearly shows that 10 speed 105 (5700?) shifters won't work with the 10 speed GRX derailleur, sadly.
https://productinfo.shimano.com/#/co...453&acid=C-453
It clearly shows that 10 speed 105 (5700?) shifters won't work with the 10 speed GRX derailleur, sadly.
04-20-20, 04:08 AM
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Hi. I recently changed my rear derailleur to the new GRX 10-speed medium cage. I am running it with my old shifters which are 105 10-speed. Before changing the rear derailleur the shifting was working flawlessly. After changing to the new rear derailleur I am having issues with shifting in the middle of the cassette. From 6-7 cog in the rear, I have to use 2 clicks to shift once. All the other gears are shifting well. Is this a compatibility issue? I read an article claiming the following "GRX400 10-speed is compatible with current Shimano Tiagra-level 10-speed groups". Is there a difference in cable pull between 10-speed Shimano and 10-speed Tiagra causing this problem? I have changed the rear derailleur hanger and outer and inner cable without any luck.
