Shimano SLX / Deore Guide And Tension Pulley Set (RD-M663, Y5XE98030, 11 teeth, 10 speed).

FOR PERSONAL NON-COMMERCIAL USE ONLY! The user of the 3D-printed pulleys assumes full responsibility for any harm or damage that may result from the use of these parts.

I've been riding on 3D-printed PETG pulleys all the last year and I was satisfied. They didn't break even after more than 3000 km of use in sandy, dirty, rainy and snowy environment.

This time I've bought a pair of new original pulleys for my bike just to measure them and make my own precise copy of the pulleys.

This is Y5XE98030 for RD-M663 (SLX), but the compatibility with my Deore RD-M610 and some other models is stated on the box: RD-M593, M610, M615, M640, M663, M670, M675, M-7000-10, 5800-SS.

The original Deore pulleys were sold as Y5XU98030 for M593, M610, M615, but they seem to be discontinued as I could only find them in a couple of online stores that sold them twice more expensive than the SLX version :) The funny thing is that they are visually the same, at least I don't see any difference on the photos.

I provide 2 versions of the model.

The "Original" version has exactly the same dimensions that I measured. This model is more like a reference. I couldn't get a precisely printed part using it as my 3D printer tends to reduce the  diameters or PETG just shrinks a little when it cools down.

The "Ender 3" version includes required adjustments so that the part printed on my Ender 3 V2 could have the correct dimensions. I made these adjustments by printing several test parts with various adjustment values until I got exactly the same measurements as the original pulleys have. It doesn't mean that your printer will print it with the same dimensions, and I give no guarantees here. If you don't like my adjustments, you are free to make your own adjustments with the "Original" version. My changes are as follows:

• All the heights were optimized for 0.08 mm layer height.
• Some diameters were increased approximately 0.15-0.27 mm as my Ender 3v2 printer tends to reduce them.  It's quite possible that you will have to increase the central hole even more for smooth rotation. I didn't want to increase the hole diameter more in the 3D model because I have one worn-out bearing that has the diameter as low as 7.80 mm instead of 7.98, and the bearing should not be too loose in the hole, so the final tuning of the hole should be made by trying the easiness of your own bearing rotation with your hands. Use a 8-mm drill bit and/or a round fine file after printing to smooth the seam and fine-tune the final hole diameter.
• The original pulleys are made from Polyoxymethylene (POM) which is rather hard and it does not bend. I use only PETG which bends easily when it is thin. It's not possible to make teeth thicker than 2.0-2.1 mm as they won't go into 10-speed chains, but I redesigned the shape of the slope from the teeth to the center so that it could start increasing the thickness of the pulley as close to the teeth as possible. Basically, it is a straight line as it is the most efficient way to start gaining the height right after the "safe" teeth line. This modification makes the Ender3 version much harder than if you print the original design from PETG.
• I've made the pockets for the nuts slightly deeper to avoid unwanted friction as I found that the nuts from older pulley sets are a bit thicker than the new ones.
• Extremely sharp edges of the tension pulley were redesigned to 0.32 mm thickness for durability.
• The pulleys are cut into 2 pieces to print them without support and then glue them.
• Three adjustment holes were added to glue both sides correctly.

PLASTIC TO USE.

I use only PETG so I cannot advice about other types of plastic. I surely don't recommend using PLA for this model as it is rather fragile and can sometimes deform under sunlight.

Transparent PETG is more preferable for maximum reliability as color additions are rumored to slightly reduce adhesion. At the other side, color PETG withstands ultraviolet better and may serve longer. In my experience, I don't see any noticeable wear in the transparent pulleys that I used last year, so if you are going to change them every year, I think the UV radiation should not be a problem. Besides, they will become covered with chain lubrication grease and dirt very soon anyway :)

PRINTING THE "ENDER3" VERSION.

Set 0.16 mm for the first layer and 0.08 mm for all the other layers in your slicer.

Print order: from outside to inside for maximum precision.

When slicing, use many perimeters (I use 5-7) and 99 bottom layers. Do not make seams on the teeth, as it reduces reliability noticeably (paint the seam manually inside the hole for the chain).

Print at 30-40 mm/s using PETG even if your printer can print faster. Set cooling fan to 40% or lower (I printed with the fan off). Slow speed is needed not only for accuracy but what's more important - for better adhesion between layers and perimeters. You don't want the pulleys to break on the road, so print them slowly.

ASSEMBLING.

The pulleys are glued from 2 parts. The main thing here is to align the parts perfectly and use really good glue (I use cyanoacrylate glue). There will be only a couple of seconds to align both parts after you applied the glue, so I've made 3 adjustment holes to help with the precise alignment. Insert 3 pieces of 1.75 mm filament into one part of the pulley and leave approximately 3-5 mm ends, make them sharp if needed. 

Make sure the other part of the pulley moves easily on these pins (increase the holes diameter with a 2-mm drill bit if needed). There are 3 ways to align these 2 pieces, but only one way is correct, so use a marker to mark the pin that is in front of the tooth (the other 2 pins will be in front of the chain holes). Mark the hole in front of the tooth on the second part as well. When you are sure that the 2 parts can be aligned easily, apply the glue on the second part and join both parts together (the marked pin should be joined with the marked hole). Press hard. When both parts are glued, remove the excess of the filament pins and smooth their ends with a hot solderer.

INSTALLATION.

The metal parts should be taken from the original worn-out pulleys. Most likely they will be a bit worn-out as well, for example, the metal bearing hole in my old guide pulley increased from 8.05 to 8.20 mm, but I think they will survive several replacements without noticeable decrease in riding experience.

The guide pulley is symmetric, so it doesn't matter how to install it. The tension pulley is not symmetric, so you should install it so that the sharp side of the teeth look towards the oncoming chain. If you are not sure, see the picture of the original pulley, it has an engraved arrow that shows the correct rotation direction.

IF THEY DON'T ROTATE.

Check that they are printed with good quality.

The original guide pulley height is 6.14 mm (without bearing).
The original tension pulley height is 6.82 mm (without bearing).
The diameter of the hole in the original tension pulley is 8.05 mm while the bearing diameter is 7.98 mm.

If the height of your pulley is higher than this or the diameter is lower, it won't work properly.
The bearing for the guide pulley has 6.52 mm height, so your pulley should have lower height.
The bearing for the tension pulley has 7.05 mm height, so your pulley should have lower height.

Use a file, engraver, dremel, etc to reduce the height or increase the hole diameter if needed.