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Shimano GRX RD 810 on 11-46t cassette, is it possible?

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Shimano GRX RD 810 on 11-46t cassette, is it possible?

Old 01-07-20, 06:59 PM
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rivfranxco
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Shimano GRX RD 810 on 11-46t cassette, is it possible?

Planning to get the GRX STI 810 along with the RD and would pair it with my existing 11-46T cassette but Shimano stated that the GRX RD only can handle up to 42T cassette. Does anyone have tried this before?
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Old 01-07-20, 11:26 PM
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I can't say for sure, but it probably will be fine. If not, try a wolftooth roadlink. I run a similar one on my MTB with an XT derailleur. It says it fits all the current Shimano road derailleurs and the 810 looks to be the same design.


Wolftooth Roadlink DM.
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Old 01-08-20, 11:20 PM
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[QUOTE=Bryan C.;21274987]I can't say for sure, but it probably will be fine. If not, try a wolftooth roadlink. I run a similar one on my MTB with an XT derailleur. It says it fits all the current Shimano road derailleurs and the 810 looks to be the same design.


That's what I'm also thinking. I have an extender like a roadlink. Well, I hope the RD alone is enough just to save weight. Lol. Thanks for the input!
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Old 01-13-20, 01:08 PM
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That would be quite a lot for the RD-RX810 , the biggest cog it can handle in the back is a 34. The RD-RX812 will handle an 11-46.
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Old 01-14-20, 07:05 PM
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If you don't care about weight you can get a SLX derailleur and a Wolftooth Tanpan since it fully supports an 11-46. I did this and it also saved me ~$15 but I haven't installed it yet. Once I do I can report back on how well it works.

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Old 01-15-20, 12:38 AM
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Originally Posted by MAGAIVER View Post
That would be quite a lot for the RD-RX810 , the biggest cog it can handle in the back is a 34. The RD-RX812 will handle an 11-46.
has anyone confirmed the rd-rx812 works with a 2x11 system yet?
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Old 01-15-20, 04:30 AM
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Originally Posted by MAGAIVER View Post
That would be quite a lot for the RD-RX810 , the biggest cog it can handle in the back is a 34. The RD-RX812 will handle an 11-46.
RD-RX810 will work with 11-40, but this would be max, i tried 11-42 and no go.
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Old 01-15-20, 06:08 AM
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Originally Posted by redlude97 View Post
has anyone confirmed the rd-rx812 works with a 2x11 system yet?
I also want to know that, I've seen the 810 used on a 2x setup with an 11-42 cassete but I'm not sure if it will work well.
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Old 01-15-20, 02:32 PM
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Originally Posted by DavidfGR View Post
RD-RX810 will work with 11-40, but this would be max, i tried 11-42 and no go.
Interesting since I got an Ultegra RX800 GS to work with a 11-42T on a 2x11 setup.

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Old 01-16-20, 12:38 AM
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Originally Posted by DarKris View Post
If you don't care about weight you can get a SLX derailleur and a Wolftooth Tanpan since it fully supports an 11-46. I did this and it also saved me ~$15 but I haven't installed it yet. Once I do I can report back on how well it works.
That was my previous setup for several months. I jüst want to have a "proper" Gravel bike groupset which doesn't mix/matching anymore.
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Old 01-16-20, 12:45 AM
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Originally Posted by MAGAIVER View Post
That would be quite a lot for the RD-RX810 , the biggest cog it can handle in the back is a 34. The RD-RX812 will handle an 11-46.
I'm talking about the 1X specific RD which Shimano stated that it could handle up to 11-42T. The 2X system just offers up to 34T only.
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Old 01-17-20, 02:32 AM
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I tried again, this time with my new 2020 Santa Cruz Stigmata, setup with 2x11 Grx Di2, and i can confirm that the rear mech works without problems with 11-42 cassette.
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Old 01-20-20, 07:09 AM
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Originally Posted by rivfranxco View Post
I'm talking about the 1X specific RD which Shimano stated that it could handle up to 11-42T. The 2X system just offers up to 34T only.
The 1x RD is the RD-RX812 the RD-RX810 is the 2x version.
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Old 01-29-20, 05:13 PM
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Originally Posted by MAGAIVER View Post
I also want to know that, I've seen the 810 used on a 2x setup with an 11-42 cassete but I'm not sure if it will work well.
https://www.cxmagazine.com/shimano-g...10-rx812-rx570

Of course, there’s a difference between what’s recommended and what actually works. Due to a mix-up, our test bike arrived with a GRX 2x RX810 crankset, front derailleur and front and rear shifters, but with a 1x RX812 rear derailleur. It did the job without complaint or issue, and I likely wouldn’t have noticed until I asked Shimano’s Nick Legan why his bike had oversized pulleys while mine did not. Legan diligently followed up, and discovered by mistake I was supplied the wrong derailleur for the 48/31 and 11-34 drivetrain.

In a day I had the proper unit.
I swapped the RX812 derailleur out for the RX810, made a few adjustments and hit the dirt again. The shifting was crisper across the two chain rings as the upper pulley of the RX800 derailleur remained consistently closer to each cog across the cassette. However, I’m thankful for the mixup, as it revealed the effectiveness of the Shimano clutch, as the 1x derailleur handled shifting duties without a chain drop, even though the drivetrain was 9 teeth over the derailleur’s stated capacity.

Similarly, the 2x derailleur can handle duty with larger-than-stated rear cogs with some aggressive B-screw adjustment. We’ve done the same with the RX800 and RX805 derailleurs. Shifting may not be optimal, but it’s certainly possible.

Shimano GRX boasts gearing versatility, but it’s actually even more than the specs indicate.
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Old 02-01-20, 07:00 PM
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Originally Posted by Bryan C. View Post
I can't say for sure, but it probably will be fine. If not, try a wolftooth roadlink. I run a similar one on my MTB with an XT derailleur. It says it fits all the current Shimano road derailleurs and the 810 looks to be the same design.


Wolftooth Roadlink DM.
We've tried them and the RoadLink/RoadLink DM/GoatLink/GoatLink11 don't significantly improve the GRX RD-RX812 performance on an 11-46. Would love to sell you one, but wouldn't feel great about being in the snake oil business.

The 11-46 exceeds Shimano's recommended 31t cage capacity, for what that's worth. But other derailleurs in their line with the same cage length are rated for much more
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Old 02-03-20, 08:21 AM
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The Evil Chamois Hagar seems to come with GRX 1x with and an 11-46 cassete, at least it has an 11-46 on this review.


https://bikerumor.com/2020/01/23/rev...road-or-trail/


I don't see why it would not work, the RD-RX812 looks a lot like the XT RD-M8000 GS rear derailleur, I would even argue that a Sunrace 11-50 may work. I run full XT8000 with a GS rear derailleur and Sunrace 11-50 on my 29er without any hanger extenders or anything extra and it works flawlessly, I'll try the 11-50 once my GRX 1x group arrives.
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Old 02-04-20, 06:46 PM
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Thanks for the link and quote. I just replaced the Ultegra 50-34 chainset and FD for a GRX 48-31 and FD, on my Checkpoint SL6. And was trying to determine the difference between and correct RD for my 2x setup, the RD-812 or RD-810. This article made it clear so now I'm planning to follow up with the GRX RD-RX810 RD with a 11-40 or 11-42 cassette..
Thanks,
John
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Old 02-12-20, 08:07 PM
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Originally Posted by DavidfGR View Post
RD-RX810 will work with 11-40, but this would be max, i tried 11-42 and no go.
I want to chime in here and confirm the RD-RX810 works with a 11-40 in a 2x.
Just picked my bike up from my LBS, they were iffy about the 11-40, telling me the Shimano specs state 34 max, but they said it worked easier than they thought it would.
I bought my Trek Checkpoint SL6 with Ultegra group, swapped out the compact 50-34 for a GRX 48-31 (w/ GRX front derailleur). But wanted to go lower so bought the RD810 and 11-40. Now I'm going to need to put some knobbier tires on as traction will be the issue now on steep rocky climbs.
John

Last edited by jwill911; 02-12-20 at 08:10 PM. Reason: typo
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Old 01-06-21, 02:36 PM
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Originally Posted by jwill911 View Post
I want to chime in here and confirm the RD-RX810 works with a 11-40 in a 2x.
Just picked my bike up from my LBS, they were iffy about the 11-40, telling me the Shimano specs state 34 max, but they said it worked easier than they thought it would.
I bought my Trek Checkpoint SL6 with Ultegra group, swapped out the compact 50-34 for a GRX 48-31 (w/ GRX front derailleur). But wanted to go lower so bought the RD810 and 11-40. Now I'm going to need to put some knobbier tires on as traction will be the issue now on steep rocky climbs.
John
Hi John,
I'm hoping to do the same thing on my diverge. Came with 48/31 GRX 810 chain rings, and 11/34 cassette, with RD810 long cage. As we know, Shimano says 34 is largest rear suggested, but I want an 11/40. Did you have to also use the Wolf tooth link to make yours work? Also, which cassette did you get? Assuming the Shimano XT CS-8000?
Thanks for any help you can provide.
David
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