Shifting Big Gears with Shimano GRX: 2x 48/31 with 11-40 XTR Cassette
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- เผยแพร่เมื่อ 28 ก.ย. 2024
- Shimano's gravel-bike specific groupset, GRX, available for Di2, mechanical, 1x and 2x drivetrains, is a milestone in the evolution of the gravel bike. Shimano didn't slap together a road / cyclocross group and call it "gravel", rather they spent close to five years developing a groupset for what is arguably the fastest-growing genre of cycling, circa 2019.
* Apologies for some camera auto-focus issues due to low-light conditions *
Shimano may arguably have the best shifting systems on the market for road, mountain and gravel, but the company has always been a little conservative. One example is the recommendations of maximum cog sizes with their derailleurs.
A perfect example is the maximum cog recommended for the company's 11-speed Dura-Ace 9100 mechanical / 9150 Di2 rear derailleurs. 30T was the stated max cog, but we debunked that myth and went all the way to 36T in another video.
The recommended maximum cog size for Shimano GRX Di2 2x or mechanical 2x is 34 teeth. However, that GRX 2x derailleur cage looks capable of handling bigger cogs. Thus, JOM of the Gravel Cyclist crew got tinkering and set about debunking Shimano's gear limits on GRX. Will GRX Di2 2x shift a 48/31 chainring combo paired to an 11-40 XTR cassette?
Links of interest:
Shifting big cogs with Shimano Dura-Ace 9100 / 9150 - wp.me/p4V4se-5oN
Shimano GRX Di2 initial impressions - wp.me/p4V4se-8vo
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I'm envious that you can post this video and not be barraged with a bunch of "why do you need such low gears?" "why not just ride a mountain bike?" "do you have chicken legs" comments that I get on my channel when I post about low gearing.
Hi Russ, as you know, there are plenty of haters out there who would never make these comments to your face. Ignore those comments / delete them. There's no rules in gravel cycling, the folks who are grumpy are better off embracing the ride experience, versus worrying about nitpicking the bikes of others. My Niner MCR 9 RDO video drops soon... I am so expecting a ton of haters on that one!
Low gears are absolutely needed. I run 11-34/50-34 on my road bike and I'm getting a PRO GR and I intend to run 11-40 with the 2x using a goatlink. Just trying to figure if the 817 will actually be the right rear D considering slant angle.
I read recently of a guy running GRX with 2x MTB crank and 11-46 for touring
@@michaelviglianco6121Shimano still makes a 2x mtb crank. It would honestly be great for touring.
@@koreydeese6899 I have an old 2x10 I'm using with 11sp. The appeal of the grx option is the shifters without something like a Tanpan
Just did this setup right now with my grx rx810 rd on a 50/34 crank. Crosschained it no problem (granted you should never crosschain anyway) and it shifts to the higher gears beautifully without any roadlinks or adapters. Only honest issue is that going down gears isn't that great.
Great! I specified this for my new Trek Checkoint 6 from Matt and the guys at Cyclescape Ballarat Victoria and it works like a charm without the noise you are experiencing
Quick update-2mm spacer and a bit of cable tightening all now hunky dory with 46-36 front and 11-40 rear-perfect! thank you
Just installed the 11-40 cassette on my GRX 810 last night and works good so far!
does it still works?
Thanks for validating my own similar experience. Praxis 48-32 crank, R7000 105 rear mech on a Sunrace 11-40 cassette with similar results on my Giant Revolt.
Hi Max, I have an Praxis 48/32 crank as well and I'm looking to put on an 11/40T cassette with a GRX deraullier Mech. Have you had any issues? any tweets/hacks?
Ali Yates I just ran the B screw out and then fiddled with the indexing until it worked acceptably. I do have to sometimes give a little extra nudge on the shifter to get it to go up (easier) down is never an issue.
I also didn’t add any extra links, though I should have 1 or 2 more because the rear mech will bind if I try for big/big. There’s still adjustment there, I just didn’t add the links as the bike was brand new when I did this.
Over 2k km and I’m very pleased and don’t mind that it’s not perfect.
Interesting. I have a Giant Revolt (Advanced 2) with that same drivetrain setup and looking to add the same cassette. This is the only hardware that you had to add? Does the 40 tooth make a significant difference on the hills? (assuming that you had a 34 stock cassette, as I do) Would you do anything differently?
@@trendsrn I use 11-40 sunrace with their extender for over 5000km and it was great addition. That 40t helps a lot when I am tired or in forests. Just the sora 9 speed sometimes annoy me and on road its hard to keep cadence, some jumps are just too wide.
The Shimano distributor in my country didn't even bother importing the medium cage (2x specific) rear derailleur, they tested the long cage 1x rear derailleur with the 2x front crank and it works
Does that apply to the RD-RX817 Di2. I have a 2x GRX coming, but I bought an 817 (separately) thinking it would work for a 11-40 rear setup. Also have a goatlink.
@@0321recon hi Bob. Wich rd did u use
@@artcaballerojr I am running the stock 815 in 2x. 40t on back with a goatlink. It has been running fine.
Right on. I know the small x small the firmware limits those gears but leaves open the bigxbig. Can u exclude bigx big using di2?
@@artcaballerojr no problems so far with an iPad and Shimano software. I use it through wi-fi and blue tooth. The only small issue I have and solved is rear derailuer adjustment, but the software handles it. I have to pick a few micro clicks to center when moving from the gravel wheel set with the 40 to my road wheel set with 34t.
Very helpful. I like the look of the GRX. I already run an 11-40 on my road bike using a Wolf Tooth Road Link. Looks like the GRX derailleur is already long enough for the 11-40.
Indeed, it works great sans the Roadlink, but the Roadlink takes any worries out of the equation. I'm reviewing a Calfee gravel bike the moment with GRX Di2 mechanical 2x and a Roadlink. Shifts very nice with an 11-40.
@@GravelCyclist I may have to send my new 817 back. I have a 2x GRX coming (PRO GR) and want (need) to have the 11-40 living in the Cascade area of WA. Have the goatlink ready.
Bob, the Goatlink works... I have been using one that arrived on the latest review bike from Calfee. An 11-40 with the 2x specific GRX mechanical derailleur works perfectly.
@@GravelCyclist Thanks a lot! Just the information I was looking for. In the video you used a 10 speed Goatlink instead of the 11 speed Goatlink, even though it's an 11 speed cassette. How come? Is the 11 speed the wrong length, and the 10 a better fit, no matter their designed purpose, or is there another reason? Thanks!
Bonus question: Running a GRX FD-R810 front & rear derailleur, 46x30 FC-RX600 crankset, and I wanna update my 105 11-34T cassette to a 40 (maybe 42) cassette. Any recommendations for what cassette I should be looking at?
Thank you so much! I just got a GRX800 equipped bike,many steep hills around here where 31/34 is not going to get it,for me.
I can totally relate... I was hoofin' a bunch of 20% gradients in Australia when 31/34 wasn't low enough... d'oh!
Shimano need a goldilocks cassettes and chainsets. 11-36 with a 44/28
SRAM also needs to produce that 11-36 for their 12-speed eTap.
Gravel Cyclist
You can use a Rotor 12 speed cassette and a KMC 12 speed chain with Sram AXS. That was verified by Rotor when I spoke to them at the Philly Bike Expo.
@@mabatz That is good information, thanks for passing this one along! The only negative is the price of that cassette... d'oh!
@@GravelCyclist I've had decent luck with a Rotor 12-speed 11-36 and Eagle chain with the SRAM 46/33 front chainset.
You can get that with a 9 speed setup mixing road and mtb components.
Thanks for the video, congratulations on your channel, I have a crank 48-31 configuration and a 11-42 cassette with Ultegra 6800 GS derailleur add Wolftooth Roadlink and it worked, but I want to adjust the chain, asks: how many links do you use in your configuration? 110 Links?
You can stop it blocking out the bottom two cogs in the small ring by changing your chainrings on etube app to 53/39 and the cassette as 11-25
Now that is an interesting tip, aka a bodge. I will check it out, thanks!
Running the same but mechanical and it works flawless. Thanks!
Awesome, good to know!
Thanks for confirming that Scott, I’m looking to try the same thing on my Secan
How do you avoid crosschaining with the mechanical, with no shift indicators? Do you keep looking down? Do you just remember? Or does it just work? I'm referring to small-small.
@@gregsullivan7408 i just look down to confirm, but you can feel it is going small-small by pedaling
@@gregsullivan7408 you sort of just feel it but looking down to confirm is the safest bet
Just as an update, Did you ever add the needed links to go big/big? If so, any issues with going small/ small? Did it still shift well?
Hi. I know that its a low group set, but did someone tried modify crank grx 600(46-30) to other and grx 400 with other freewheel?
Thanks for that, I had no idea about the bell button either!
Hi. How about RX-810 (48/31T) + XT 11-40 cassete + RX812 RD?
Hey there great video, I've been binching your videos and you totally sold me on GRX. Since I discovered your channel, I managed to get my hands on 2 sets of GRX 11 speed sets. One is a GRX 817 which I'll run as a 1 x and the other has a GRX 815 derailleur. I know you are not a big fan of 1 x but I'm wondering if one can run the 1 x GRX 815 with a 11-40t cassette on the back? Would I need to modify anything or put spacers at bb area to push crank set out or such or apart from the B screw perhaps? Hope you are doing well.
Will this be the same with the GRX RD-RX400 (2x10spd) version? Thinking of upgrading my Tiagra 4700 rear mech to the GRX but also going up in cassette size too. I understand the 4700 and RX400 have the same cable pull so its ok that way, but not sure about cassette sizes. Thanks, Dan.
I'm curious about 2 setups: 1) can a Sram Rival AXS handle any cassette larger than a 44t (like a 46 or 48t) ?
I have not tried it, only because I have not had a larger 12 speed cassette available.
I think if you use di2, mayby try at 817rd configure at app with for example 52-36 chainring set with 3 or 4 cos less at big chainring and when you try click on your right to up cog, should get to smaller chainring and down 2 or 3 cogs. I suppose it can be working. Best way i think will be change a cage and bearings for bigger.
Hey there... Question: Would the RD-RX400 (which is 10sp) shift to a 40 cog as well? You know, Tiagra brifters are way more affordable than 105 and the RD-RX400 is also a bit cheaper... I am kind of on a budget here...
Just asked my mechanic and he said it could work with a roadlink/goatlink but you would sacrifice smooth shifting for that
Actually -
I run a mechanical GRX RD-RX810 rear derailleur with a 48/32 front crankset and an 11-36 cassette: No problems whatsoever. My chain is longer though (was sized for a 11-34 HG cassette originally)
curious how is your Big/Big and small/small get any rub? i have same and yes never cross chain but with it was a little smoother.
Do you mean 48/31 or are there other crank sets for the GRX that you cant get in Europe?
thank you for that Info. What about using the longcache version RD-GRX 817 instead if building up a new bike (as i do)? Would it be a worse shifting performance with 11-32 cassette because of the longer lever arm?
have you set such bike up? did it work?
Nice video. Is this RD-RX815 mid cage or RD-RX817 long cage?
Thank you for all the amazing things you show us. I sincerely love your channel and your social media feeds. This video is not complete and can lead people into thinking this drivetrain is workable and reliable for everyone.
Can you show us a video of what this gear combination looks like in the small/small gear combination? Please show a video of what happens you you accidentally shift into the large/large gear combination. Only when you do that will you have a truly functional drivetrain.
I'm sorry to be negative. This is the first thing that I've seen you post that isn't complete.
Best wishes.
UPDATE: The video does actually show small/small gear combination. The video is also clear about the limitations. My mistake on that. What a better person than me would have said was that it really isn’t safe to run a drivetrain where you can’t hit all the gears.
I came away from the video thinking that all I have to do is add 2 or 3 more links to the chain and all will be perfect. That is absolutely the case IF the rear derailleur can take up the slack. That is what I’d like to see.
I’m sorry that I did not accurately say that in my original post.
Hey there, the video does show small-small. Sorry, I am not going to shift into big-big without a new and longer chain being fitted... with the current chain, the frame / hanger would likely be damaged. I was quite clear about that in the video. There are limitations to my videos, and destroying parts isn't one of them.
Gravel Cyclist : Very good! Thank you. There was time before I saw the video and when I wrote the reply. I forgot that you DID show that. You were clear on the limitations. I am seriously old school in that I don’t consider something working until it can hit all the gears.
Again: Thank you for all that you post and share with the community. It is much appreciated.
Gravel Cyclist : I’m sorry that my reply sounds like I’m an angry, old troll. That wasn’t my intent.
@@PedroGringo No need to apologize, your reply was perfectly fine, thank you for following and enjoying my content. I do appreciate the feedback.
do you think the same applies to the mechanic, using the 812 can take on the 46/30 and run an 11-40 cassette?
with enough chain length, yes.
Hi there. I would like to change my GRX 810 chainring 46/30 for ultergra 50/34 chainrings. Do I need to replace the front derailleur as well? I love my gravel bike but I feel I need bigger chainrings. Please let me know. Thank you. Marcello
Ciao Marcello. I have not tried the 50/34 combination with the GRX Di2 derailleur, but I don't expect you'll have any issues. It works perfectly with 48/31, so I expect the two teeth jump, and 16 teeth difference between rings will be just fine. Good luck!
Hard to tell in the video, but there doesn't seem to be much clearance between the top of the chain in the FD in the 48x35.
There were no issues, but don't go big big!
Thank you for the video, what kind of 11-36 cassette do you suggest to buy? (I currently have GRX-810 with ultegra R800 11-32T)
Take a look at the SRAM PG1170 11-36.
@@GravelCyclist does turning the b-screw in too much damage the hanger on frame or does it depend on frame's hanger? i will be getting a wilier jena and putting a 11-36t
Would this work as well with the GRX 600 with the 30-46 chainring combo?
We have gotten that combo working on another crank with 46/30, so I don't see why it wouldn't work. Best of luck if you try!
@@GravelCyclist Have you tried a 1x setup with a 38t chainring combined with a 11-46 cassette?
@@janislionel1715 I ride GRX 800 1x11 with an 11-46 XT cassette and a 40t ring, Works perfectly.
Do i need the road link with 46/30 and 11/40 on GRX 810 ?
Nope, works perfectly, without a wolf link. I set min up last week and no issues even wiht crosschaining big to big, I had to remove two links form a new chain 114 links for my bike.
Do you need a spacer when fitting the 40-11 cassette?
Yes, if using with an 11-speed hub.
@@GravelCyclist Thanks!
Thank you! Those Wankers at cc.road basically said you can't do that LOL. I blew them up over that. Thanks again for proving my point. With adding a wolf tooth road link you could run a 42-11 cassette with ease and have the big big shifting available.
Hey richard, still happy with the setup? Which front chain combination and chain length do you use?
Thanks a lot! Just the information I was looking for. In the video you used a 10 speed Goatlink instead of the 11 speed Goatlink, even though it's an 11 speed cassette. How come? Is the 11 speed the wrong length, and the 10 a better fit, no matter their designed purpose, or is there another reason? Thanks!
Bonus question: Running a GRX FD-R810 front & rear derailleur, 46x30 FC-RX600 crankset, and I wanna update my 105 11-34T cassette to a 40 (maybe 42) cassette. Any recommendations for what cassette I should be looking at?
Because all we had when the video was recorded was a 10-speed Goatlink. For your other question, STX or XT level, I believe 40T or 42T is available for both, all depends on your budget.
great; can one do it with the 46/30 chainrings?
I don't see why not... it should be a simpler proposition considering those chainrings are smaller... LOVE 46/30!
@@GravelCyclist thanks a lot! you are doing a superb job and helping tons of people!
Guess who is going 46/30 to 11/40 hehe. 30/40 now we are talking...
Shame there isn’t an option to block the big-big combination
I haven't played with the Di2 firmware but there is a way to block it in the semi-synchro mode... if I have the terminology wrong, please forgive me. I have an Ocoee Boundary in for review with Ultegra Di2 (RX rear derailleur), and it blocks the big / big (it then automatically drops to the small ring and shifts two gears down the cassette. On the small ring, when the 6th or 7th cog is engaged, it shifts to the big ring, avoiding excessive cross chaining. I'll have to plug in the Di2 tool and take a look and report back. I believe some of what I'm talking about depends on certain hardware elements being present... I think the latest generation of the battery being one.
@@GravelCyclist will it damage/break anything if you do shift big big by mistake (w std chain) if you dont limit?
@@invishand3 when the chain is not long enough, it will rip the rear derailleur off.
@@GravelCyclist Okay, now that's cool!
Why do you say "trend setters"?!
This is a very strange thing to ask. It is a friendly greeting... if you didn't catch it, I'm Australian.
Maybe because we (and JOM obviously) were riding gravel before it was cool so we can call ourselves trend setters.
@@krlgrudzinski Spot on and cheers!
Hilarious 😆 Btw, did Rodney Rude coin that phrase, or was it already in use?
This is a terrible idea. You should never run a drivetrain that can't get into its big-big combination without jamming and destroying components. You think now that you won't ever absentmindedly shift into that combination, but anything can and will happen. Far better to run a longer chain and accept some chain droop in the low-low combinations (which you also shouldn't use).
All that said, it's good to know that the RD-RX810 can fit a 40t sprocket! I have to wonder how tightening the B-screw that far would affect the crispness of shifts throughout the range though.
That's a fat chain wrap! I'm on board...just not for that price.
Mechanical is a wee bit cheaper.
Thx for the confidence builder! I think it works, but there are so many warnings against it...I have been riding on 11-36 31/48 since I bought it last summer, with no issues . Trying out a 11-42 with a Roadlink, and a longer chain, and it seems to work perfectly, (though not in the big-big--it will go there, but I wouldn't ride it like that). Big test will be fully loaded next week!
how many extra links did you add and how did it work out?
The RX800-GS & RX805-GS clutched road rear derailleurs work with a 42T low gear, so the GRX RD’s should as well.
Confirmative. Even road GS versions can handle 11-40 with compact 50/34 chainrings. I did it with R7000 GS. Now moved to RX-810.
How many links work with this set up?
@@buzzman4860 a standard 114 links Shimano chain is enough if you don't go crazy with cross-chaining (leave two largest sprockets to the small chainring).
Have you done it with derailer extender?
Or just on it's own?
@@hellgart666 It was mounted on the RD hanger of LOOK 765 gravel directly.
Hi, how do I manage to run a 50/34 with an 11-40? Could you leave the complete configuration of rear derailleurs, front derailleurs, shifters, chainrings, sprockets and chain? I don't have much idea of bike mechanics, but I could buy what I need, I would appreciate it!
:)
Hi,
Thanks for sharing. On my low end gravel i have a rear derailleur R7000 with a 11-40 cassette on a 135mm QR hub. It works perfectly. My crankset is a 50/34 road crankset with road chain line. I had to tighten the same rear screw to make the body derailleur to avoid the upper jockey wheel / chain to touch the big cog
Just got a bike with 2x grx800 mechanical. What size spacer did you use for the XTR cassette?
old comment I know, but was it a 1.85mm spacer?
@@gpeaes yes. Ultimately I upgraded my dt Swiss 370 hubs from 3 pawl to 36t with the ratchet ln upgrade kit and it came with the shorter 11speed mtn bike free hub.
The second the spring comes around I'll be purchasing the GRX groupset for my Slate Rigid 😊. Thanks again!
(Edit added)
I made a comment on here a while ago, but I think it is time for an an update. Back when I wrote last time, I just tweaked the B-screw and tried it out in the stand but never got around to really use it. I then went back to the original set up without any other trials done.
But only a few days ago I got a Wolftooth Roadlink in the mail, and yesterday I installed it on my bike along with the same SLX 11-40 cassette I used in my initial trials.
No problems what so ever with shifting having the bike in the mec stand, all smooth and precise. And best of all; I can allow myself to accidentally cross chain without any problems, as the chain length is just enough for big/big on my set up. I run 2x11, front rings 31-48.
Hoping to get some miles in this weekend, and will report back.
What I am after is some bike packing compatibility, and with this set up I will get about 24.5 gear inches on 700-35 wheels (if I read the charts correctly) compared to the original 28.8 inches. This is not below 20, which is sort of the magic limit for serious touring, but it is more than 10% improvement over the original and that is not bad.
Edit: Works a charm. No problems at all, shifting is smooth and even, and shifting feels as if the set up coming from the Shimano factory.
Nice one! I greatly appreciate you chiming in with this helpful information.
@@GravelCyclist Now not only tried on flat ground but today ridden for 41 km over loads of coarse gravel and some steeper gradients.
Like a charm. A bliss to use. Totally worth it.
I ran the calculator numbers on what you have (same as what im after ) and came out to 21.1 gear inches with 170 cranks. Not sure why we are diff. I would like to be around 20. Thanks
Cheers mate, thx for the inspiration! I even went with an 11-42 XT casette in addition with a roadlink DM on Easton 47-32 chainrings. Even with the stock 11-34 chain big/big isn't critical. Cervelo Aspero GRX mechanical.
Is your GRX 600 or 810?
@@christopherchan8676 810
Hi! I'm a big fan of your videos.
I got into the Unbound 100 and trying to figure out gearing of my GRX-1x bike. I currently have 40t chainring and 34-11 cassette. I'm wondering If can install a 40t-11 Cassette as noted on your videos and how to figure out if my chain length is enough. My derailleur is RD-RX812. Now, capability is a thing but not sure if I'm overthinking it and 40t is not necessary... that is a different story.
My fitness/skill level: I guess I will be finishing behind the middle of the pack or close, if at all...
Thanks very much!
Hey, did anyone try to set up the grx rear derailleur with a xt 26/36 crankset? I need easy gears 🙈 cheers from Germany
I'm building a set of more aggressive gravel wheels with an 11-36 cassette to go with my GRX 810 RD and 46x30 chainrings. Not going to push my luck going any larger than 36 on the cassette. Hoping I don't have to tweak any derailleur settings. That 0.83 ratio and 22.9 gear inches should plenty low for me.
I plan to have 2 wheelsets (one with 11-36 cassette and larger and aggressive gravel tires installed, and one that's more road oriented at 11-28 with more tarmac-friendly tires) that I can quickly swap out of on this bike depending where I'm riding. Seems like an easier thing to do than getting all the tools out and changing the cassette and tires each time. JOM, is this something you ever do?
I'm doing the same right now. For a usual road commute I just swap my offroad/adventure wheelset (11-40t cassette with gravel tires) with a road wheelset (11-34t with smooth tires for tarmac).
God I love gravel bikes
I also want to switch to a 11-36 & 30/46 combo. How did it work out? Is the shifting still smooth? Anything particular i need to be aware of before making the changes?
@@markay_ Sorry, I just noticed your reply! I put the 11-36 on one bike with 34-48 rings and used a Roadlink hanger on the back. It works just fine. I put the 11-40 on my other bike with the GRX drivetrain with 46-30 rings , but it was a bit tight and the B-screw was hitting the tab at an angle. Replaced the stock derailleur hanger with a Wolftooth Goatlink and it works perfectly. The B screw has a very solid bite now. I've ridden this setup for 18 months and ~2000 miles on each bike without issue.
Best of luck!
I love seeing what can be done. Thanks for sharing the experiment. It would be nice to see what adding a link of chain would do. Seems like it would be safer and maybe more practical to avoid small-small than big-big.
Hi Sir, hope you can help me on this one. Would this set-up work? Ultegra FC-R8000 50x34x172.5mm 11-Spd, Deore 11x42 Cassette and GRX 812 RD?
Big chainring to big cock is the limiting factor. As you avoid that combination and only demonstrate up to 35 - you‘re only 1 tooth beyond a 11-34 cassette in terms of capacity.. Like running a 11-35 cassette regarding critical combination. No surprise it works as it‘s almost within official range. However nice to know the rear derailleur is capable of 40 teeth within the b screw range.
Thx for sharing...
Anybody have experience or suggestion to use RD GRX812 (11-42, originally designed for 1 buy crank) combine with GRX 2 buy crank (48-31, so it will be 2x11-42)?
Is it works or must change/ modified RD GRX812 with longer cage? If yes, any suggestion what type of cage compatible with?
Very impressed pushing the capacity to a whopping 46 on a rear mech Shimano lists as 40 max. This gives me confidence to swap my 11-34 for 11-40 on my Lynskey with the mechanical GRX (RD-RX810) RD with my 46/33 front chainrings, so a capacity of 42. I knew the cog size could be push easily, even more with a road link, but thought capacity was kind of baked in, unless you did something wild like swap cages to a long cage from a mountain bike or something as radical. Shimano really is super conservative on specs.
What GRX 400 works with 11-40 or 11-42 cassette?
I have a 1X setup, but want to go to 2x. Is there a configuration where I can I use my RD817 (1X rd) with a double chainring crankset?
Ricardo, I understand the RD817 derailleur will work pretty well with a 2x crankset. Bear in mind, this isn't something I've tried. Good luck!
I've read the 817 and 815 are completely different components. This guy seems informed, but I'm thinking with the right chain length and goatlink it may be a good option - derailleur slant? handsonbike.blogspot.com/2019/12/grx-rear-derailleur-rd-rx815-vs-rd-rx817.html
I have just made the jump, when my clutch is on in the big ring it won’t shift up the cassette past the second gear unless I adjust rhe b screw but then it won’t shift into the 40t while in the little chain ring
Is it possible to try GRX 46x30 with 11-40? I think this may just work without any limitations, you would need a shorter chain for the big/big, so less demand on chain wrap capacity...
I don't have the GRX 46x30 crankset, but, we have ran 46x30 with the FSA Adventure crank and the Ultegra Di2 RX derailleur / 11-40... it worked no problem, so I would expect the same from GRX.
Sweet. Looking forward to GRX 2x mechanical on the new steed. Will plan on 2nd cassette, chain & quicklinks.
Put this on my GRX 810 and didn't have to do a thing besides turning the B screw 4 turns. Can't believe it was this easy; thanks!
In the video it sounds to me like you get chain contact with the front derailer? Would love to here from your experience with that 👍
Does it have to be the XTR cassette? Those are currently out of stock here in DK :/
Maybe this is an Di2 only hack that works with the gear blocking. I don’t think the rear derailleur would cope with the correctly sized chain and do big big and small small. I’d worry running mechanical grx when in either of those 2 combos the chain would be too tight or too loose. Saying that I’d be very happy to be proved wrong!
I just completed a mechanical GRX build with the 48/31 and 11-40 combo and I’m happy to report that I can safely shift in the big/big and small/small combo without any issues with chain tension. Not that I would ever run in those combos, but it’s comforting to know that if I ever mis-shifted, my drivetrain won’t explode under me.
My gravel bike is set up with 50/34 Absolute Black oval chain rings and a hybrid 14-42 Shimano cassette using an RX800-GS RD fitted with Kogel 12T/14T pulleys and I can shift big-big and small-small with no issues.
@@ryangabriel9146 I figured it would work just fine, except I need a little bit more chain for what I was attempting in the video.
When the chain wears out, I'll have to do a test of 48 x 40 with a properly sized chain... I think it will work, and I could do a Di2 block if needed.
@@ryangabriel9146 is that with the 810 or 812 rear mech? Did you need a wolf tooth or similar adapter?
can you exclude big big by way of the Di2?
You can if you set it up in automatic mode.
this looked so smooth I went for the shimano GRX 2x11 rear derailleur adn the XTR 11-40 casssette but no matter what I do I can't get it to move onto the 40 tooth cassette. I have a 46/36 chainset . I have moved the b limit screw to max. I ahve't put alonger chain on (Still 114 links though that has been enough on other videos) and am just not able to work out why it's not working for me? Do I just need a wolf tooth link?
I would try a 34T small chainring... compared to the big ring, they are very cheap. Alternatively, you could try the Wolf tooth link, I used those a few years ago.
will look at this-realise that the M8000 cassette is a mountain bike cassette so may need a spacer-have one on order and will see if that sorts it first..it was very close!
Did you adjust the index of the rear derailleur?
I tried the same today and it works fine, if the clutch is disengaged. If I activate the clutch it wont shift over tooth 15. Is it because I have an old ultegra battery?
I doubt it is to do with the battery. Something very dodgy happening here.
I have a question it would bei Interesting if anybode has experience with it. My bike cube nuroad pro tiagra 4700 shifters grx600 30-46 rear mec grx 400 10 Speed. I would Like to Install a Hg cs500 11-42 casette. Is that possible (Shimano says max 36 rear)? Furthermore so i need to Install a other chain?
Hello from Germany: I have GRX 815 DI2 with 48/32 and 11-34.
Can I install a 11-36 or a XT 11-40 with the same derallieur? Does also a SRAM cassette works?
Thanks for the help!
I just installed an 11-40T XTR cassette and was wondering 2 things.
1) Is there a way to manually update the size of the cassette in the Shimano's E-Tube app?
2) Is there a way to limit in the software shifting into large front/large rear cogs? Just want to make sure I do not switch into it on accident.
This is GREAT! Exactly what I was looking for, as I've wanted an extra few teeth in the back for easier climbing, but hesitated to try going larger than 34 because I thought it'd mean adding a new derailleur or that it wouldn't play well with the front chain rings. Will try this on my Obed Boundary GRX 2X11 this weekend (and I really appreciated your Boundary review as well). Thanks!
Does anyone have experience whether this works long term? Thinking about going 11-40 with my GRX RX810 rear derailleur.
I used this setup albeit on a different bike in this video - th-cam.com/video/Pru6rGZFICs/w-d-xo.html
@@GravelCyclist Thanks for sharing. How long did you use it? Did it hold up?
Probably will also take 42t. You might need to try another revolution on the B screw
Does 11-40 or 11-42 cassette work with rx400 RD? Thamks
Can I do 46-30 front 11s 11-42 cogs with rx810 RD?
I think it would work, but, trying it for yourself is the only way to answer the question, sorry. I don't have a GRX bike with a 46/30 or that cassette at the moment to even test.
@@GravelCyclist would it work with other cassettes than the XTR - those are currently out of stock in DK ;)
@@GravelCyclist And by the way - excellent and precise video. You deserve more than 52K subs.
@@zilverstone Many thanks, I appreciate the kind words.
Shimano state that the max/min smallest sprocket must be an 11t, but will it work with a 13t for a smallest sprocket?
Just dropped bike and broke RD-8000 GS, and just ordered GRX-8000
Is that a long cage mech, or the standard one please?
Why they didn't design it this way as the norm baffles me. Not everyone is able to climb hills with ease. This is a gravel groupset and they leaned too "road" from the get go.
At minimum, I think they should have spec'd 46/30 chainrings on the higher zoot version of the GRX crankset. It is available on the less spendy version. I rode 11-40 with the setup in this video albeit a different bike, at the 2023 Rock Cobbler. 31 x 40 low gear was fantastic, along with a 116 link Shimano chain.
I’m running 11x40 on the back with 50/34 on the front. I do have a bit of a longer chain and can go to the 40 in the big ring on the front.
Nice one, awesome to see someone else experimenting.
I had a grx 400 than i turned into: deore 11/42 casstte (10 gears, because grx 400 can only shift 10 gears i guess), grx 812 derailleure and a 11gear-chain.... works perfect along the whole range - so there is no 30/46 in front and 11/42 in the back....
Is IT grx 30/46 in front and 11/42 cassete in rear with 812RD ?
@@paweljasnowski yepp, it is... works perfect, only chain length was problem so, 30 front and 11 back (small/smallest) the chain is a bit lose... but works... didnt used it cause if i need this i change to 46 in front and smth. Between gear 4-7 in back... should be the same.... 😉 oh, i see i loose a "w" in my first post... "now" was i wanted to type...
Hey, how much chainlinks do you use at this combination?
Since this video where I have used this setup a few times now, a complete 116 link chain worked perfectly.
I honestly dig that shift noise.
To be safe you should get a new chain and make it long enough.
Yes, very good advice. I rode this configuration on a personal bike in California earlier this year. The Shimano chain was straight out of the box, 116 links, no cutting. Worked perfectly with the same gearing combination in this video.
I wander how the long cage does on 11-34. I'm probably about to go grx once my 105 front rings go. with 4K on them they don't show any signs of stopping tho.
you can mix and match all GRX and 105/ultegra/dura-ace parts without problems. also, 11-34 will work fine.
@@Digi20 So for GRX di2, all you have to buy is the front and rear derailleurs, battery and shifters?
@@s.stallone5350 Do you Upgrade from an excisting build? You could also buy the shifters alone if that is what you are after
Will the rx810 pair perfectly with a 105 50/34 crank?
I've not tried it but I don't see why it wouldn't work. 17 tooth gap on GRX 48/31 vs 16 tooth gap on 50/34.
Will the GRX 2x accommodate a 650b wheel? That is, is the front derailleur 'out of the way'? Deciding whether to go 1x by 2x and want a system that will accomodate 700c and 650b. Thanks!
Currently riding my latest review bike, the T-Lab X3 with GRX Di2 2x... have 650b + WTB Resolute fitted (42mm) at the moment... so much room... 47mm tyres will be no problems, ditto on 50's. Shimano tested the crap out of this stuff, they are ahead of the game!
2x will work up to around a 50mm tire. maybe 54mm (2.1 inch) depending on your frame geometry and tire. but the clearence gets very tight even for the chain when you are in small-big. so a studded tire with mudd on it might lead to problems in very gnarly scenarious when you go over 50mm.
Very nice.👌🏻
That is super low. Damn. I'm running 32-34 and it's very low.
31 x 40 may come in handy if you're climbing a 25% grade, assuming you can get traction, and assuming you don't tip over backwards :) Some technique involved for sure.
@@GravelCyclist Haha for sure. I have no problems where I live with my .94 ratio as of yet.
What's the actual difference between RX810 and RX812? Cage length? Could you run an RX812 in a double front setup as well?
basically the 812 has another design that puts the jokey wheel further back/down to allow for the bigger cassetes in 1x drive trains. however it does not have the capacity for double chainrings, you would need to change the cage for that.
@@Digi20 I'm a bit confused. If 810 can do 11-40 in a 2x setup, then why a longer cage in 812 would hamper the same setup?
is that the derailleur with the long cage or the one classified for 34 teeth?
The derailleur classified for 34T, the 2x model.
@@GravelCyclist Is the GRX RX400 RD compatible with a 10spd 11-42T cassette? I'm planning to go 2x10 with a 50-34 crankset. Would there by any problems in shifting? Thank you
@@kevinchristopherviray722 You need to try this yourself I am afraid. I don't have that configuration to try myself, you will have to tinker!
Hi, what do you think RX400 rd will work with 11-42 (10 speed)? Also capacity is 41t, but in tech spec 36t is a max gog
"Capacity" refers to how much chain slack the derailleur can safely hold, not cog clearance. You take the difference between the largest and smallest cog on the cassette, and add the difference between the big and small ring on the crankset, and that's how much "capacity" you need. For example, an 11-36 cassette with a 46-30 crankset is:
(36 -11) + (46 - 30) = (25) + (16) = 41T minimum RD capacity needed
An Rx400 rear derailleur can accommodate such a set up, which means that with the chain length set to survive a big-big gear selection without damage, it still has enough chain tension (by Shimano's standards) when you select small-small.
With enough fiddling on the B-screw, you can probably get a RX-400 rd to clear a 40T cog on most bikes. Maybe even a 42T. If you have the conventional 16T difference (or more) between your largest and smallest chain rings, however, the derailleur might not have enough range of pivot motion to safely accommodate both the extremes (big-big, small-small).
Also, because of the extra b-screw tension, the gaps between the the jockey wheel and the cogs on the small end of the cassette will be larger than Shimano thinks it should be. The same is true if you use a RoadLink or something similar to relocate the rear derailleur to clear a larger cog. Theoretically, the large gaps would make the shifting less precise, and the derailleur less tolerant of slight horizontal misalignment, thus more susceptible to chattering or ghost-shifting. As seen in this (and many other) videos, however, Shimano's rear derailleurs seem, in reality, to be pretty tolerant of such gaps.
@@gpatrick95 that's a very comprehensive reply. Would you say that running a 42t cassette on RX400 derailleur would be more manageable if you run a single front chainring?
@@SiopaoSauc3 This is my plan as well. With a 36 or 38 T chainring. Do you think it can clear the 42 T cassette even with the clutch on? 🤔
@@troyjusticecabrera7284 GRX 400 works with 11-42 in your bike?
@@SiopaoSauc3 It works?
Did you ever try this out with a few more links to the chain?
Negative.
@@GravelCyclist Just ordered the 11-40 cassette and will see if I get it to work large/large on a mechanical GRX810. I really want to get that to work, because I know that once tired and a bit out of sync, it is possible to forget not to cross the chain. Would be great for bike touring too. I'll add as many links as the bike allows for on small/small, and try gently...
@@Hermod_Hermit Good luck!
@@GravelCyclist Got the cassette, and initial trials on my spare wheelset shows it works. I got "plenty" of chain left without having to add links so perhaps my chain is a bit long for the standard 11-34 cassette.
Anyways, the main diff I've seen so far is that the bigger jumps in actual cog dia gives rougher gear changes, the silk smooth shifting on original cassette is gone. However, I have not tweaked the rear derailleur settings besides screwing in the B screw 4.5 turns.
I will give it a more thorough go next weekend, this I am off on some road riding (we can still do that here in Sweden, but I do go alone) and do not want to fiddle about experementing just now.
But yeah, initial trials looks promising, small-small and large-large both working.
Just got my giant revolt. Was thinking if putting ultegra rx800 derailer as that's clutched. Is it an easy swap as I am on full 105 group?
No problem!
criz florez
Yes, direct replacement.
Will it work with shimano 7000 groupset????
Yes
GS R7000 RD
Ugis LA did you have to add an extension to the rear derailler hanger.?
@@nancyelliott8007 depends on chainstay length
Very helpful video! When switching from the 11/34 to 11/40 XTR cassette, did you have to add or change any spacers? Thank you
What cassette gear ratio do you use in this video. It seems it is 11-36... Thank you ...
Read the title of the video.