Shimano Deore / SLX tension and guide pulley

Update 2025-04-09: I've bought a pair of new SLX/Deore pulleys, measured and duplicated it. I recommend you to use the new version. 

Update 2024-05-26: added a special version of the guide pulley with a metal bearing that can be removed from the original worn-out guide pulley. Revised the guide (centeron) pulley height from 7.0 to 6.0 mm to comply with the original Deore pulley height (6.12 mm with 6.5 mm bushing).  Tension pulley height is still 6.8 mm although my old one is 6.6 mm with 7.0 mm bushing (not sure, maybe it's too worn out). Use a file or sandpaper to remove 0.2 mm if needed. This tension pulley model is difficult to modify for some unknown reason, maybe I'll make a new one in FreeCAD some day later. Previous versions are preserved in a separate folder. 

PS: 1500+ km so far with an old worn-out chain and cassette, the initial pulleys still look good and usable! I think they are eternal :) I will try the new version with the metal bearing when I decide to replace the chain with a new one.

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These are not my models, I only made halves of them to print them without support. I downloaded 8 different models of pulleys from internet and selected 2 models that look more like the original ones, print well and don't require metal bearings. As these models are not available at Printables, I decided to upload them here to easily find them later. The original authors and the links to their models are mentioned below. Both models have CC-Attribution license.

I printed the halves without support using PETG (0.12 mm layer height, random seam position for strength) and glued them together. This is better than printing the original models with support. Metal parts were taken from the old original pulleys.

Depending on your printer and printing settings you may need to increase the central hole and remove some plastic from the sides manually to ensure easy rotation of the pulleys.

The guide pulley has longer teeth and it is the upper one.
The tension pulley has smaller teeth and it is the lower one.

I tested them in real life with Shimano Deore Shadow RD-M610-SGS (10 speed chain) and they work better than I expected. I don't see any serious wear. The following photos show the new pulleys and the pulleys that were used during 450 km in a sandy and dirty environment with an old worn-out chain:

I even took a ride at -5 degrees Celsius a few times and the pulleys didn't break! All the teeth are in place and their size is fine, the shifter works easy and correct with them. I have no idea how long they will last, but they are surely good if you cannot buy new original pulleys but still need to ride your bike :) And the price of 3D-printed pulleys is ridiculously low in comparison with the price of the original Shimano pulleys. These ones can also be used with a worn-out chain if you don't want to kill the new original expensive pulleys with it.

I'm going to use them in the future for daily rides and will replace them with the original ones only for serious touring trips that last many days far away from home and require maximum reliability from all the equipment.