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Anyone tried the GRX RX812 derailleur with an 11-46T cassette?

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Anyone tried the GRX RX812 derailleur with an 11-46T cassette?

Old 08-21-20, 06:21 PM
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howardv
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Anyone tried the GRX RX812 derailleur with an 11-46T cassette?

Got a new gravel bike with GRX 11-speed drivetrain (single chainring). It has the GRX RD-RX812 rear derailleur, which according to Shimano's site will work with up to a 42T cassette. I have a XT CS-M8000 11-42 cassette, but would really like a bit more climbing power. I noticed the CS-M8000 11 speed cassette is also available in 11-46T. Would my current derailleur handle it, even though Shimano says only 42? I know people have pushed the Shimano guidelines successfully in the past, wonder if anyone has tried this specific set-up.
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Old 08-21-20, 06:44 PM
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I have not tried this but generally Shimano specs are conservative and you can get away with the next size up cassette HOWEVER with a 4 tooth increase you may need a longer chain to provide sufficient slack on the largest cog.
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Old 08-22-20, 03:11 AM
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gus6464
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Yep no issues. Had to get extra couple of links though.

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Old 08-22-20, 09:55 AM
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Originally Posted by gus6464 View Post
Yep no issues. Had to get extra couple of links though.
Thank you so much! Exactly what I was hoping. I believe this will give me that little extra climbing power that I'm looking for.
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Old 08-23-20, 03:22 PM
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gus6464
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Originally Posted by howardv View Post
Thank you so much! Exactly what I was hoping. I believe this will give me that little extra climbing power that I'm looking for.
For links go to your lbs and ask them if they have any extras from builds or chain replacements. For example on mine I just need 3 more links so it's silly to buy a second chain just for that.
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Old 12-16-20, 04:09 PM
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Originally Posted by gus6464 View Post
Yep no issues. Had to get extra couple of links though.

Nice setup. Thinking about going this route. Which cassette model from Shimano (11-46) will fit a road hub body for a gravel build? Which one are you using?

Thanks!
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