Compatibility quest...
 

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[Closed] Compatibility question

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Will a Shimano GRX rear derailleur (and levers) work with an XTR 11 speed 11-42 cassette?


 
Posted : 11/02/2021 10:18 am
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Maybe. It'll work with a 40T.


 
Posted : 11/02/2021 10:21 am
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Is this a trick question? There isn't an XTR 11-42T 11 speed cassette. XTR is 11-40, if you want a 42T you need XT or below.


 
Posted : 11/02/2021 11:55 am
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The RD-RX812 rear derailleur is compatible with mtb cassettes with a 42T low sprocket max.

https://bike.shimano.com/en-US/product/component/grx-11-speed/RD-RX812.html


 
Posted : 11/02/2021 12:03 pm
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My bad, it's likely to be an XT cassette, but the question remains the same.


 
Posted : 11/02/2021 12:11 pm
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Thanks Thols2. Looks like it should work fine then.


 
Posted : 11/02/2021 12:12 pm
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Yep, my Fugio is running GRX 1 x 11 with an 11-42T XT cassette.


 
Posted : 11/02/2021 12:15 pm
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Someone one here had it running with the deore 51t didn’t they? Plenty of room


 
Posted : 11/02/2021 3:14 pm
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Follow-on question. I think the GRX range falls into Shimano's road range. If I use GRX600 levers could I still use my XT rear derailleur and cassette, or is the cable pull ratio wrong. Would I therefore need one of those in-line adaptors to continue using this derailleur. Thanks again for help.


 
Posted : 15/02/2021 11:49 am
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https://www.bikeradar.com/advice/buyers-guides/a-complete-guide-to-rear-derailleurs/

current generation (10-, 11- and 12-speed) Shimano road and mountain bike components are not inter-compatible with each other because they use different cable pull ratios. For example, you couldn’t use a set of road shifters with a mountain bike rear derailleur.

http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/


 
Posted : 15/02/2021 12:08 pm

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