Compatibility of 38T chainrings to Deore crank

Question

My bike (Canyon Pathlite 5) has an "FC-M5100-1, DEORE" crankset and a "Shimano Deore M5100 11s 11-51" cassette. Instead of the 32 teeth on the front chainring, I'd like to change to 38 teeth (maybe elliptical) (of course with an appropriate longer chain).
Are there any hidden compatibility issues, or is any chainring with the following specifications suitable?

96 mm BCD
4-arm asymmetrical
1x11 Shimano

Examples:

https://www.bike-components.de/de/Stronglight/HT3-Kettenblatt-Shimano-FC-M9000-11-fach-4-Arm-96-mm-Lochkreis-p58108/
https://www.bike-components.de/de/Wolf-Tooth-Components/96-BCD-Kettenblatt-fuer-Shimano-XT-M8000-SLX-M7000-p63953/
https://www.bike-discount.de/de/kaufen/katana-razorblade-oval-narrow-wide-kettenblatt-96mm-990307
https://r2-bike.com/GARBARUK-Kettenblatt-Round-1-fach-narrow-wide-LK-96-Shimano-XTR-M-9000-9020-Kurbel_1
https://r2-bike.com/GARBARUK-Chainring-Melon-oval-1-speed-narrow-wide-BCD-96-Shimano-XTR-M-9000-9020-Crank

thelawnet · Accepted Answer

There is no difference between a Shimano 11-speed 1x chainring and a 10-speed one. There is a slightly difference in the OUTER ring(s) of a 2x or 3x chainset, because 11-speed chains are slightly narrower and this affects shifting from smaller to larger. However single speed rings are completely identical between 10 & 11 speed, so you don't need to worry about 1x '11' per se.
A 1x drivetrain is quite simple upfront with much less to go wrong in terms of poor shifting performance etc. Normally you'd have to worry about derailleur capacity etc. but with only one chainring that's not an issue.
The only considerations might be:

material - some materials will be lighter, which is not a major concern at this size, others might be more durable e.g. hardened steel
narrow/wide - this is a good idea for chain retention on 1x drivetrains
BCD & bolt pattern - you have noted this already
price - if you buy something very expensive you could end up spending more than a new chainset, where your current one is a simple one with solid arms, whereas more expensive models have hollow (lighter, possibly stiffer) arms. So you don't probably want something too complicated

Argenti Apparatus · Answer

As others have said, there should be no problem in terms of compatibility with the rest of the drivetrain.
The replacement ring should give the same chain line as the existing crank, but a ring made for the specific crank should do this.
The compatibility issue you may run into is chainstay clearance. Obviously the chainstays flare outwards towards the hub, and s bigger ring may interfere with the drive side stay. You need a certain minimum clearance to allow for frame flex during hard pedaling.

Tobias Hermann · Answer

To answer my own question from practical experience:
I now have mounted a "Garbaruk Melon Narrow-Wide Chainring for Shimano FC-M6-/M7-/M8000 - Oval - 4-Arm - 96mm asymmetrical".
It works fine but did not fit out-of-the-box. The chainring has indentations for the spider to go in, but the 4 arms on the crankset do not all have the same width, as you can see here. So I had to either increase the width of the indentation on the chainring or decrease the width of the spider arm. Since I only had a somewhat big metal file on hand, I opted for honing down the arm. It now looks like this.
Side effect: Due to the general shape of the new chainring (indentation), my front chainline is now 2 mm more lateral compared to before (with the old "flat" chainring). It's now centered over the 9th sprocket of the 11-cassette (was between 8th and 9th before). It still might be ok, since statistically, I use the outer/smaller sprockets a lot more on my usual terrain. Also, I can't use spacers to move the chainring more medial again, because it's already quite close to the frame/chainstay. (But it does not grind it even when the frame is deforming during sprints.)

Compatibility of 38T chainrings to Deore crank

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