Shimano GRX RD-RX812 with an 11-46 Cassette. Will this work? Low Gearing on a Gravel Bike.

Officially the GRX RD-RX812 doesn't support cassettes larger than 11-42. However, it is not uncommon for the derailleur to work with sprockets larger than what documentation specifies. In this case I will try to make it work with 11-46 cassette to achieve super-low gearing on a drop-bar bike.

[gearedforadventure]

BTW: The chain should be longer, I just didn't have any spare links to add. Everything works so far, but to prevent any premature wear I will definitely extend the chain by at least 2 links in the near future.

UPDATE: Installed 118 links chain and now it is perfect.

[simongschwend]

I just mounted a 11-46 cassette to my Cube Nuroad C62 pro (from 2020) and it works just fine. Minor adjustments at the derailleur were necessary, but now im happy. Thanks for the Video!

[gfelkner]

I appreciate this. I'm currently running a GRX 810 with an 11x40, but occasionally need a lower gear. In the past I have switched to a smaller chainring (from 38 to 34), at the expense of my top gear. I just ordered the GRX 812, and I already have an 11x46 on the shelf from an earlier experiment. This should be a better solution, and it will probably (hopefully?) improve my shifting a bit when I run the 11x40, which is most of the time.

The GRX-810 is pretty impressive in it's own ways, I even managed to run it in 2x with 44x30 chainrings and 11x40 cassette. It had just enough chain wrap and did a reasonably good job in the back, but the front derailleur adjustment was a struggle. Something always seemed to find a way to rub. I enjoyed the range it provided, but I eventually gave up on it and reverted back to 1x.

[Piplodocus]

I found my range not quite as wide as I'd like stock (slightly ran out of top end with the 38t chainring that came with it). But I love GRX and have the dropper lever and in-line brakes. So I bought a SRAM XD driver freehub for my wheels and put a SRAM 10-42 on my GRX instead. Works great. Lighter cassette than the 11-42 Shimano that came on it. SRAM 10-42 with a 38t is pretty much the same range as an 11-46 with a 42t chainring. (25 to 106 gear inches)

[sznib]

So, 4 tooth above specification. The same situation with RD-M675; rated to 36T max, works fine with 40T cassette without any modifications, and "H" screw isn't screwed to max.

[gordonh]

it seems you can still add some chain links to avoid the derailleur so tight in 46T.

[hansvandemortel]

Dude That's very nice.

So I could use Tiagra 4700 2x10 speed brifters with the GRX 812 and the Deore 10 speed 11-46 with a Grx 10 sp 30-46 crank

Yehoo that would be nice bikebacking 125 kg up the Alpes.

Am i right >?

[Leo-gtbx]

I am seriously questioning B links on standard RDs. Is it not just a cause for more flex and wear?

[jeanbravo]

Hi, a GRX 812 can work with a 11 speed casset 9-46 XD?

[alejandrogonzalezdelgado]

Nice video. Would it work with the Goatlink with the same chain length? It may help loosening a bit the derraileur tension.

[koenvanniekerk]

I have the same question. Would be the ultimate high range low gear solution…

[EricPeelMusic]

To anyone reading this. 36x46 is NOT low enough for adventure, bikepacking, touring etc. And the jump from 37 to 46 is and will always be, no matter how much you want it not to be, stupid and uncomfortable. It is one of the worst cassettes Shimano has ever came out with and they are continuing to overcompensate for their poor choice by coming out with a full lineup of mtb cassettes with big cogs that have steps TOO CLOSE. The best mtb cassette Shimano has ever made is their 11-40t 11s. Pair this with a 42/26 crankset, and you’ll be much happier with evenly spaced steps, a low enough low gear and a high enough high gear.

[alre]

Great video! I wonder if it would take an 11-52! Haha

[luketoms]

Did you have to adjust the th3 b screw

[miguelropero]

Hello.

I have a gravel Canyon with Shimano grx derailleur and brakes.

Originally with:
- 2 chainrings 30-46
- Shimano GRX RX400 GS long rear derailleur
- I changed the 10s 11-34 cassette to a 11-42 shimano 10s to climb better. I put a sunrace extender so the derailleur wouldn't hit the cassette and a slightly longer chain.
It doesn't work very well ...
That's why I want to try this change that you have put, the GRX Shadow Plus RD-RX812.
Do you think this derailleur (of 11s) would go well with my 10s cassette and my 10s grx shifter and my 2 chairings?
Thanks

[raphaelgaleano]

La estructura es exactamente igual a un rd m8000 o rd m5120 ✌🏼

[mikaelle]

Compared to 11-42 cassette, is the 11-46 a bit noisier? Tnx

[therealSIRBOOM]

Was a spacer required for the cassette?

[dalesaco]

Hello! I wanted to ask, is it possible to use GRX RX812 rear derailleur with a 2x11 setup? By the way my chainring is 30T/46T. And for my cassette, it is 11T - 42T.

[stemac]

I can safely say the 812 works with an 11-46