I currently have a problem with my most recent bike build that is driving me nuts - maybe I am missing something, maybe I have made some rookie mistake, if anyone has an idea on what to do / try, it would be really appreciated!
I recently changed my 2x drivetrain on my 2nd generation Canyon Grail to a 1x drive train. It previously had a 2x Shimano GRX Di2 12speed drivetrain, of which I kept STIs, brakes, and the crank. Here’s what I did:
took off the two chainrings and put on the Wolftooth GRX 1x Aero chainring (46 tooth)
as a rear derailleur I installed the Shimano XTR Di2 9250 SGS according to the official Shimano manual
changed the freehub body on the DT Swiss GRC 1100 wheelset to microspline and installed an XTR 10-51 cassette (CS-M9200)
waxed the new chain (XTR CN-M9100) with Silca secret chain blend, using the Strip Chip according to the manual
set up and micro adjusted the derailleur according to the official Shimano manual (including chain sizing and chain routing through the derailleur)
The result was a drive train that was shifted super fast and crisp and was pretty quiet - at first. It got very noisy after 50-100km, especially in the larger cogs. Now I am totally aware that a 1x drive train will not be as quiet as a 2x drive train, but it sounds a lot noisier than a SRAM Eagle 1x drive train I have on my MTB and what I remember of an old 1x SRAM Rival XPLR drivetrain I had on an old CX bike. Here’s what I tried to solve the issue:
installed a new UDH derailleur hanger (Carbon Ti X-Hanger UDH) and checked the alignment - it is perfectly aligned
read that I should actually install not the DT Swiss Microspline, but the DT Swiss Microspline ROAD freehub body and did that - cleaned everything, greased according to manual, checked that all cogs of the cassette are correctly aligned before re-tightening
checked derailleur was installed correctly and with the correct torque
topped up the chain with Silca Super Secret Chain Lube every two rides or so
Result: it is pretty quiet after topping up with the Chain Lube, but then gets pretty noisy again fast. Now I am unsure if that is just normal and something I have to live with, or if I am missing something. Two additional hints (maybe?):
when indexing correctly according to the manual (5th cog, inwards till noise, then 5 clicks outward) shifting works fine on all cogs BUT from the second smallest to third smallest cog. Here it jumps and jumps but doesn’t actually shift, only if I microadjust 2-3 clicks inwards
while setting it up again for the 100th time the other day, I thought I had solved the issue: the chain was running quietly, shifting was crisp and fast, and all with a freshly wiped chain but without any topped up wax. Then I noticed that I hadn’t yet tightened the through axle of the rear wheel to spec yet (it says on the frame: min 15nm, max 20nm). I tightened to spec and chain ran OK but not as quiet / smooth and the whole drive train became noisy again after 20km of riding on the topped up chain. I double checked if I had really installed the Microspline ROAD freehub body with the correct end cap, as that is supposed to be 2mm wider - but based on it running smoothly with a losely tightened through axle it looks like it actually needs even more space to run correctly?
Sorry for the wall of text and a big THANK YOU to anyone willing to help!
Yes, definitely. Question is how to solve it / how others got this to work. For example, some of the Canyon ATR Pros have been running this exact same setup.
So I just found out in the derailleur manual that the XTR Di2 9250 SGS is optimized for a 55mm chainline, while the GRX crank has a 49.7mm chainline. My understanding was that the GRX 1x derailleure (827) was just a rebranded XT derailleur, so interchangeable - but could it be that there is actually a difference between them, being the chainline? Unfortunately I can’t find the information regarding the recommended chainline in the Shimano GRX 827 manual.
If there is a difference in chainline between the XTR and the GRX derailleur, I guess I need to change the derailleur - or is there a way to bring my existing crankset from 50 to 55mm chainline?
Regardless of the noise issue, it’s worth checking that you have the correct freehub before you do anything else, or this could cause serious issues. Once the end caps are fitted, there shouldn’t be any movement in the freehub body, and tightening the thru axle shouldn’t make a difference to the function or position of the freehub. Address this first, as it may also be affecting your shifting.
RE Derailleur chainline, don’t forget that the XTR rear derailleur will be designed to work with a 55mm chainline (measured from the centreline of the bike) when fitted to a Boost 148mm frame. If you’re mounting it to a 142mm rear end, that will move the derailleur 3mm inboard relative to the centreline, so will also permit a chainring which is 3mm further inboard…
If the issue is noise in the largest sprockets, moving the chainring further outboard will likely make the noise worse - the chain will get noisier the further away from straight it becomes (effectively like cross-chaining a 2x drivetrain). Running a wide-ratio 1x drivetrain with a large chainring, on a bike with short chainstays will ultimately lead to the chain running at extreme angles when in the largest sprockets, no matter what you do.
To identify if the noise is coming from the chainring or the derailleur, shift into the 51t sprocket and spin the cranks very slowly, and watch the chain as it runs onto the chainring. Does the chain engage smoothly with the chainring teeth, or does the chain initially ride high on the teeth, causing the plates of the chain to rub down against the side of the teeth before the rollers drop into position? Equally, observe the chain along the bottom run as it is picked up by the lower jockey wheel - does it run smoothly, or does the jockey wheel seem to catch against the side of the chain before sitting into position?
Hopefully this is clear, I probably haven’t explained this very well.
Thanks to the OP for this post as I am planning almost exactly the same upgrade to my Crux 4 this winter. Please let us know how you get on!
I have been asking myself the same question about the GRX 12 speed Di2 mech and hoped it would be designed differently to allow it to run with the narrower gravel chain line compared to 55mm boost?
I too remember that when the new GRX mech was released the reviewers said it was just a rebadged XTR mech, hence the query.
In my experience the Shimano chains are pretty noisy. I have had good luck with subbing in a YBN chain. I can’t notice a difference in shifting, but YMMV.
Also, when it comes to Shimano 12sp chains, you can use any narrow-wide chainring you want (no need for specific HG+ teeth) by replacing the Shimano quick link with a YBN quick link.
Re Chainline: makes sense, but that then still leaves 2mm difference. I don‘t know how much of an issue that is, though. Also a lot of Pros are riding the same setup on their Gravel Bikes, wondering how they are making it work. Especially because lots of them are using not a GRX, but a Dura Ace crank which should make chainline issues even worse (44,5mm if I remember correctly on DA, compared to 50mm on GRX).
Re noise check: I’m totally aware that this system will be nowhere as quiet as my 2x road bike, but still it seems to loud. More like “sounds like the hanger is bent” loud, but it is perfectly straight. The noise seems to come primarily from the derailleur, hard to distinguish but a little more from the lower pulley wheel. I also think it has to be something with the chainline as it was noticeable better when I forgot to tighten the through axle to torque, as described in my original post.
@Noah_Schabacker thanks for the hint, maybe I’ll try that, too, but only as an “add on” once the basic setup seems ok
Would be really interesting if someone on this forum has made such a setup work, or knows how the pros are doing it, or knows if the GRX 827 is actually different regarding chain line than XT / XTR (which should then theoretically solve the problem if it’s optimized for the GRX crank set chainline)
The other thing to note - the 1x GRX crank has a 50mm chainline. If you’re using a 2x crank with the chainring in the outer position, the chainring will be slightly further outboard than it would be on a 1x crank - the 2x chainline is measured to the middle of the two chainrings.
That said, that will make more of a difference to chainring noise and wear in the low gears than it will to the jockey wheel noise in the high gears…
Also worth considering, the pros might not be too fussed about accelerated wear, so might overlook a little bit of noise in order to run their preferred setup… I’ve seen some sketchy sh*t on pro bikes
It could be worth checking si.shimano to see if the derailleur cages are the same between XT and GRX - that would suggest the angle of the jockey wheels is the same, unless the knuckle itself is angled instead. I don’t know though
Other things to check: are you using the correct endcaps for the road-freehub, is the chain laid up in the right direction, and are you using the correct version of the WT chainring type for the chain in question?
Mind that the 425mm chainstays on your bike only exacerbates things if something is misaligned, from a geometrical point-of-view.
Canyon also uses a similar setup now, but on a bike with 435mm chainstays. And from the looks it seems they use a smaller chainring, which may also help with chain lenght between the ring and the big sprockets:
Interesting, because I have a similar setup with the same cassette, derailleur, a GRX 610 crank with Shimano 42t GRX ring, and while it’s not the most quiet drivetrain I’ve ever used, it’s not annoyingly loud. It’s installed on a bike with 425 chainstays.
As far as I know (and I might well be wrong) there is only one GRX crank, which can be used as a 2x crankset with a chainline of 47.x mm and as a 1x crankset with a chainline of roughly 50mm.
Good idea - unfortunately I haven’t found that information. What I have found, though - “RD-M9250-xx are optimized for the chain line 55mm and O.L.D. 148 mm”. It can work on other configurations as listed below, but may not be optimal:
For the GRX827, I can’t find the corresponding information - but, as the system is optimized for the chainline of the 1x system, it should be optimized for the 50mm chainline and therefore different than the 9250?
Yes, I also suspected this, but I double checked and it is the “MSR” endcap for the freehub. The chain is put on with the text facing outwards, the chainring is the Dropstop ST version of the WT chainring.
Yes, definitely - but it was also already used on the v2 of the Grail (this is with the GRX 827, but I also saw it with the XTR). That’s pretty much exactly my setup, same wheelset etc.:
Yes, the crankarms with integrated spider are the same for 1x and 2x GRX (once confirmed to me by a Shimano customer service rep). The difference lies in (the dishing of) the chainrings.
Regarding that similar Grail v2 setup: could you perhaps reach out to the team/rider to ask for info?
The Shimano quick link causes the chain to derail at the chainring. If you replace it with a YBN quick link that shouldn’t happen. However, I’ve only done this with Wolf Tooth chainrings, so I can’t speak to how it works with a Shimano narrow-wide.
