Bikepacking gearing with GRX Di2

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tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

Nikoras wrote:
Tue Jun 30, 2020 5:19 am
Sooo I'm guessing there's something preventing me from using shimano's XT cranks? Something like this https://bike.shimano.com/en-EU/product/ ... 00-B2.html 36-26T would give me a really nice spiny setup for bikepacking and looks in line with tour divide rigs.
From the Shimano FC-M8000-B2 page (https://bike.shimano.com/en-EU/product/ ... 00-B2.html): "Chainline 3 mm outboard, . - It requires special dimension of frame which cassette position and front derailleur mount position are 3 mm outboard., . - Only E type and D type front derailleur are compatible with the special frame"

Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

Man...with all the stuff the bike industry tries to sell me that I don't need, it's a little ridiculous how hard Shimano wants to make it to achieve MTB gearing with dropbars.

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Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

I'm adding the Bearclaw Beaux Jaxon to my consideration. The SRAM force1 spec is adequate gearing. The titanium is gorgeous. Much more aggressive geometry than the Cutthroat but can still fit a 2.35 29er tire.I guess the two downsides are price, and the youtuber Path Less Peddaled noted that the high trail made the handling a bit squirrely on slow climbs.

Mimmo89
Posts: 58
Joined: Sat Jul 20, 2019 12:09 pm

by Mimmo89

pdlpsher1 wrote:You want more gearing and yes, it's very annoying Shimano decided not to offer super-low gearing. But fear not you can make a modification to the GRX RD by using a long cage (SGS). Then you can run 11-40, 11-42, or 11-46 cassette on the back. Open the video link and expand the video description. Good luck.

https://www.youtube.com/watch?v=7kUxmkuJWNg

Content of this video:
The original RX812 rear shifting inner and outer plate are changed to the XT RD-M8000-SGS super long cage rear derailleur to support the front double-speed crank, and further support the rear derailleur to 11-46T. (The results will are like the attached video)
.
The following parts are testing in the video:
1. FC-6800 50-34T
2. CS-M8000 11-46T
3. FD-5800
4. RD-RX812 w/RD-M8000-SGS plates
5. CN-HG701

Required parts.
1. Shimano GRX RD-RX812 1x11 speed rear derailleur x1.
2. Shimano XT RD-M8000-SGS Outer Plate x1.
3. Shimano XT RD-M8000-SGS Inter Plate x1.
Has anyone actually tried this?

(As in..out in the real world, for a period longer than a test on a workstand)

I'm interested..

Sent from my CLT-L09 using Tapatalk


Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

Mimmo89 wrote:
Fri Jul 03, 2020 10:17 pm
pdlpsher1 wrote:You want more gearing and yes, it's very annoying Shimano decided not to offer super-low gearing. But fear not you can make a modification to the GRX RD by using a long cage (SGS). Then you can run 11-40, 11-42, or 11-46 cassette on the back. Open the video link and expand the video description. Good luck.

https://www.youtube.com/watch?v=7kUxmkuJWNg

Content of this video:
The original RX812 rear shifting inner and outer plate are changed to the XT RD-M8000-SGS super long cage rear derailleur to support the front double-speed crank, and further support the rear derailleur to 11-46T. (The results will are like the attached video)
.
The following parts are testing in the video:
1. FC-6800 50-34T
2. CS-M8000 11-46T
3. FD-5800
4. RD-RX812 w/RD-M8000-SGS plates
5. CN-HG701

Required parts.
1. Shimano GRX RD-RX812 1x11 speed rear derailleur x1.
2. Shimano XT RD-M8000-SGS Outer Plate x1.
3. Shimano XT RD-M8000-SGS Inter Plate x1.
Has anyone actually tried this?

(As in..out in the real world, for a period longer than a test on a workstand)

I'm interested..

Sent from my CLT-L09 using Tapatalk
I too am very interested in this. https://www.youtube.com/watch?v=sRgLG1uP_uo This guy claims to have ridden it for 800 miles with the 11-40 cassette and it's been fine. I would be more comfortable trying it this way (just unwinding the B-screw and maybe attaching a new derailleur hanger) than anything messing with the actual derailleur plates.

Frisco
Posts: 147
Joined: Sat May 09, 2009 6:23 pm
Location: Bay Area, CA

by Frisco

I have been using Easton 46/30 with 11-42 XT cassette and Ultegra Di2. It is the older 805 derailleur, not GRX, and I didn’t replace the cage or use a goatlink. I have about 5k miles on it.

Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

Update: Decided to go with a Cutty but got to their customer service and with reguards to the inventory question:

"More than likely not until sometime this winter. Hopefully that doesn’t change!"

Ouch.

Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

Followup for the curious. A specialized Diverge Pro became available so I ended up pulling the trigger on it despite my bank account's protests. I realized that this is likely the only opporunity I'll have to get some bikepacking in (and therefore actually spending my vacation time) while also getting a sweet bike I can take for gravel day rides, and maybe even some races should those become a thing again. The cutty and the Tour Divide will have to wait, though I always knew it was the case for the latter. Perhaps another N+1 a year from now :).

So all I have to do to turn this gravel speed machine into a bikepacking rig is fit a 36T, or 38T chainring. Think I'll need to shorten the chain for that?

lowftp
Posts: 19
Joined: Thu Feb 06, 2020 11:57 pm

by lowftp

I had an additional question about a GRX/XTR setup. I really like the GRX shifters, but need some additional range for climbing. Something like this:

Shifters: GRX 815 Di2
Cranks: XTR M9000 with a 36T chainring
Derailleur: XTR M9050 GS Di2
Cassette: XT 11-46

I'm hoping these would play nice on my Diverge frameset, but I'm not familiar with the mountain side of Shimano offerings. I'm also considering all GRX (shifters, cranks, derailleur) with the Garbaruk cage replacement, but the parts would take a while to get and I can only get a 38T chainring for GRX cranks.

Thanks for any suggestions.

User avatar
pdlpsher1
Posts: 4016
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

This combo will work very nicely. Personally I prefer XTR RD over GRX RD. GRX is Ultegra grade and XTR is Dura Ace grade. The motor on the XTR is larger and has more torque to overcome a high clutch setting. And in theory XTR will also be more realiable than GRX in the long-term. The only downside is cost.

If you are only planning to run 1x then chain wrap capacity is not an issue, hence the Garbaruk cage is not needed. The GRX RD is only rated for a max cog of 42, whereas the XTR is rated for a 46. So the XTR RD will allow the upper pulley to track more closely to the cog should you run a 11-46. The GRX RD will likely work with a 11-46 but shifting won't be as crisp as the XTR.

If you are thinking about running a 2x with all GRX parts you can do a cage conversion using the Shimano part. Link provided below. This conversion will probably work better and cheaper than the Garbaruk conversion. With the XTR RD SGS you can run 2x with a 11-40. If you are buying the XTR RD I'd go for the SGS and not the GS. This would give you more options down the road should you decide to go 2x.

https://www.youtube.com/watch?v=7kUxmkuJWNg

lowftp
Posts: 19
Joined: Thu Feb 06, 2020 11:57 pm

by lowftp

pdlpsher1 wrote:
Wed Aug 05, 2020 3:54 am
This combo will work very nicely. Personally I prefer XTR RD over GRX RD. GRX is Ultegra grade and XTR is Dura Ace grade. The motor on the XTR is larger and has more torque to overcome a high clutch setting. And in theory XTR will also be more realiable than GRX in the long-term. The only downside is cost.

If you are only planning to run 1x then chain wrap capacity is not an issue, hence the Garbaruk cage is not needed. The GRX RD is only rated for a max cog of 42, whereas the XTR is rated for a 46. So the XTR RD will allow the upper pulley to track more closely to the cog should you run a 11-46. The GRX RD will likely work with a 11-46 but shifting won't be as crisp as the XTR.

If you are thinking about running a 2x with all GRX parts you can do a cage conversion using the Shimano part. Link provided below. This conversion will probably work better and cheaper than the Garbaruk conversion. With the XTR RD SGS you can run 2x with a 11-40. If you are buying the XTR RD I'd go for the SGS and not the GS. This would give you more options down the road should you decide to go 2x.

https://www.youtube.com/watch?v=7kUxmkuJWNg
Awesome, just the information I was looking for to help validate my thinking. I will move to the XTR SGS, to allow future flexibility per your suggestion. Only challenge with M9000 series is finding stock for certain parts (I prefer a 165 crank but those are hens teeth).

One additional question, I should be able to use a 68mm XTR or Dura Ace bottom bracket for this non-boost crank, correct?

robertbb
Posts: 2179
Joined: Thu Jul 23, 2009 3:35 am

by robertbb

Nikoras wrote:
Tue Jun 30, 2020 7:50 pm
Man...with all the stuff the bike industry tries to sell me that I don't need, it's a little ridiculous how hard Shimano wants to make it to achieve MTB gearing with dropbars.
So true!

User avatar
pdlpsher1
Posts: 4016
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

I have the XTR SGS RD on my tandem and it works really well as a 2x system. You will enjoy it either as a 1x or 2x. The pulley cage is carbon and exquisitely finished with a clear coat. It looks awesome.

I can't answer your crank question.

Good luck with your build. I've heard nothing but rave reviews on the GRX shift levers.

lowftp
Posts: 19
Joined: Thu Feb 06, 2020 11:57 pm

by lowftp

pdlpsher1 wrote:
Wed Aug 05, 2020 6:21 pm
I have the XTR SGS RD on my tandem and it works really well as a 2x system. You will enjoy it either as a 1x or 2x. The pulley cage is carbon and exquisitely finished with a clear coat. It looks awesome.

I can't answer your crank question.

Good luck with your build. I've heard nothing but rave reviews on the GRX shift levers.
Thank you. In doing some additional research it seems I should be able to use the XTR bottom bracket with the appropriate spacers, as the crank specs 68 and 73mm. We'll see when I get it, but I suspect I should be able make it work.

Time to start scouring for parts!

Nikoras
Posts: 107
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

tomh79 wrote:
Tue Jun 30, 2020 8:30 am
Nikoras wrote:
Tue Jun 30, 2020 5:19 am
Sooo I'm guessing there's something preventing me from using shimano's XT cranks? Something like this https://bike.shimano.com/en-EU/product/ ... 00-B2.html 36-26T would give me a really nice spiny setup for bikepacking and looks in line with tour divide rigs.
From the Shimano FC-M8000-B2 page (https://bike.shimano.com/en-EU/product/ ... 00-B2.html): "Chainline 3 mm outboard, . - It requires special dimension of frame which cassette position and front derailleur mount position are 3 mm outboard., . - Only E type and D type front derailleur are compatible with the special frame"
Alright...revisiting this a bit late but I'm actually going to be building this thing...apparently the 3mm outboard chainring is just to accommadate Boost spacing which is required by the Cutthroat's frame dimensions, therefore XT cranks should work. Now I'm just wondering about XTR vs GRX di2 front and rear derailleurs. Planning on running a 26/36T front with an 11-40 rear. Doesn't give me much top end, but hey it's loaded touring.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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