Crunchy Shimano GRX 1x

I got a new bike just before Thanksgiving and Ive really been enjoying it, except the drivetrain. Its got the 800 level Shimano GRX 1x and it feels… crunchy. Is this just a GRX 1x thing or is something out of whack?On the trainer I have it in the 6th or 7th gear, so the chainline is a straight as possible, but its still noisey. I just swapped to a freshly waxed chain today and it didnt help.

Previous bike had Ultegra 6800 and was always silent and buttery smooth. 1x mountain bike drivetrains I’ve had here way smoother and quieter. Shifting seems to be a little slow, but I just figured it was because of a 11-34 cassette instead of the old 11-28.


What trainer are you using?
(wheel-on or wheel-off)

If it’s wheel-off with a cassette inatalled.on the trainer, its possible the indexing on the rear derailleur may not match up as well as the prior bike, without adjustments.

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Its a wheel on Wahoo Kickr Snap. I’ll double check that. I experimented a little with micro-downshifting and that didnt seem to affect it. I just pressed the shift lever a smidge to see if things lined up and got quieter. Didnt help. FWIW it doesnt sound like a shifter indexed in the wrong place, but I’m open to any and all suggestions.

Try playing around with the end adjustment screw and look at chain length as well. I don’t have GRX but the Eagle gear on my XC bike did something similar until I fine tuned the derailer adjustment.

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I don’t recommend changing the limit screws (end adjusters mentioned) unless you are having issues at the max or min gear. They do nothing to impact the other 9 gears in use.


I was talking about adjusting the chain gap. That’s what I’d normally call it.
I’m not sure why it’s referred to as end adjustment in the Shimano manual.

The Eagle gear runs like a dog if you don’t get it right. All 12 gears.

PS. The clutch system can also make things seem less than buttery smooth IME. Easy to test that by simply flicking the lever.

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GRX is just as good as Ultegra, HOWEVER with 1x systems you have a lot more chain cross. So yes, its louder and good clean and lube is necessary to keep it silent.

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Time for an embarrassing confession: It is possible - and for whatever reason it happened to me when switching to GRX - to put the chain on the wrong side in between the two pulley wheels at the derailleur. Everything works fine - but it makes noise. It took me an embarrassing long time to figure that out. I just thought GRX is louder…

If you are not as daft as I am, it might also be just be a new drivetrain and waxing that is louder. Noise wise wet lube would be quieter.


I did the exact same thing when I got my SRAM Force 1x :joy:

Using chainrings and jockey wheels that have narrow/wide spacing, the rear derailleur clutch, and 1x gearing will all make it less “buttery.” I spent forever trying to get my Force 1x to run as smoothly as my road bike, but it just isn’t going to happen.


Ok, that makes more sense. The common term is the B Screw (or B-Tension) adjustment, and set upper pulley to cassette cog spacing. Definitely worth a look and can lead to noise if note done well.

This video at 13:45 covers it well.


Thanks for the replies, everyone. Ill double check the B Screw. Admittedly, Ive got a 11-34 cassette on the Gravel Wheels and an 11-32 on the road wheels cassette and trainer wheel. I was hoping to be able to swap back and forth without the need to adjust since the 2 cassettes are similar. Thanks again everyone!

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do you have the clutch ‘on’ or ‘off’?

Ive had the clutch off for riding indoors, which is where the noise really started to bug me. I can also feel the crunchiness in my feet through the pedals and shoes, which is very strange.

A couple of people mentioned this above. I know I’ve done it. :rofl:

All the best.


i did it, too! Somehow its different than Ultegra and I grinded down half the aluminium until I recognized. well…


Ive done that too! I did double check that. Its all good.

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Your OP motivated me to tidy up my XTR/XT drive train. It’s much the same as the GRX.
You can definitely feel the narrow/wide tooth engagement on the chainring. I’m not sure I’d call it crunchy, but it’s noticeable when side by side with an Ultegra.
Those narrow/wide chain rings sure do hold onto the chain though.

My MTB drive trains are always crunchy after a ride anyway. I’m finding it quite funny how I pamper my road bike vs the MTBs.
MTB= Hose off the lot (often myself included) and give it a bounce to shake off the excess.
ROAD= Gently wipe things down with a clean rag.
How would I treat a gravel bike? :thinking: Would my wife notice a 4th bike?


I’m also curious as to how a waxed chain is affecting the sound. Ive been doing waxed chains for a few years now and Ive got one of my “old” chains from the previous bike on there now. I’ve checked the wear with a tool and its less than 0.5, but maybe its time to get moving on getting 3 new waxed chains into service since I already have them.

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I wanted to check in here after a few more weeks. I put a new chain, freshly waxed on the bike and it sounds much better. It is a KMC chain (came with the bike) instead of the Dura Ace that I ran before and that Ill be running. It could be the freshly waxed chain is quieter, it usually is. I could also be that its a new chain and the old had probably 2,000 waxed miles on it.

The chain that was noisy was one that had been waxed and then dunked in cold water. I dont usually do the cold water dunk so maybe that was part of the issue? More wax in the plates and less flexibility so more rub on the cassette? Anyway, this round of waxing I did not do the cold water shock like OZ recommends.

I also did a 1 hour “run in” of a Dura Ace chain with the factory grease. Everything was very quiet with the factory grease.

this might be dumb, but…

you’re using a wheel-on trainer, and you’re getting “crunchiness” only when its on the trainer? and its the same wheel that you use outside without crunch? or its a different wheel?

I feel like you should be able to sherlock holmes this.