MacRide Headset Spacer Threadless MTB / Gravel / Urban

This is a 3D Printable Pure Nylon (no fibers) MacRide (or Mac Ride) Seat Headset Spacer model for 1-1/8 steer tube. Preferred thicknesses are 12.5mm & 20mm. Printed in Easy PA, 100% infill, zero supports, 3+ walls. Save yourself 22$ USD for shipping a new one. 

If you want the most robust version, go with the 20mm spacer. It will not break printing it in PA. Maybe would be a good PA-CF or PA-HT candidate, but less fibers means more tough for PA (less brittle). 

If you want the most robust lower stack version, go with the 12.5mm version. Still super tough in Sunlu Easy PA. 

The 10mm spacer is printable, but they have all cracked on me. If you were to machine a spacer, this would be the model to use. Or if you have a printer that can do a different support material, that breaks off easy, you could try that. But the deep groove and ledges lead to a lot of stress on the internal groove corners, which leads to cracking. 

Purchasing

If you don't have a 3D printer and would like to purchase this item, I would be happy to print and ship it to you. Send me a printables message. Located in USA but will ship globally if required. Shipping will vary and affect cost. I have some in stock so just provide me a zip code and I can give you a quote. Currently it’s about $15 shipped for 4 (2x 12.5, 2x 20), but that is no guarantee. If I have an ugly misprint I’ll throw that in so you can cut it up and see for yourself how tough it is. I used it downhill MTBing (lift access) with my 5y/o and it’s held up great, and has not loosened up. 

Printing

See latest update for Orca Slicer file.

Recommend materials:

SUNLU Easy PA - currently ~$35 USD/kg

• Printed both 10, 12.5 and 20mm versions - so far so good!

OrcaSlicer File added, again.

NOTES

Although I reverse engineered this spacer I strongly recommend supporting MacRide as a company, over other “copies” that shall not be named. They're a great bunch and I mtb'd with my two sons, and now my daughter with the seats. I have two and they're easy to add/remove before/after a ride. I've crashed with them and you basically cradle your kid as you fall and bash your own elbows into the ground. They're still attached to your bike with the foot pieces so have been completely fine in each case. 

https://mac-ride.com/products/black-mac-ride-child-bike-seat

https://mac-ride.com/products/1-1-8-spacer

UPDATE 2026/03/10

• Evolved my design a bit more. I've moved the latest/best files to a new folder and archived/obsoleted the rest. Again, if you have a way to machine the 10mm spacer, or print w/ support material, it absolutely can be done. But for single filament FDM printers, my latest 12.5mm and 20mm designs are tough, and are good enough to do downhill laps with your kid and MacRide!

UPDATE 2025/08/11

• Came up with a better design that resists cracking, with big 3mm chamfers on the inner edge. So far Easy PA is the way to go. The layer adhesion is much better, especially with "Iron all solid layers" on with rectilinear pattern. Bambu Studio and Orca 2.3 file provided. Stls of the new models provided. No need to Iron with this design and Easy PA

UPDATE 2025/07/03

• I did a few things.

1. Upped the ID of the spacer to 28.9mm from 28.5. 

2. Added a 20mm thick version that should be a little beefier and less prone to cracking.

3. I also retried flat printing with the "Iron all solid layers" setting, and tree supports.

4. Infill should be some form of monotonic, and not concentric

• With my concentrically printed part failing originally, I'm hoping the monotonic layer setup, and ironing, helps improve layer adhesion and strengthen the part. This doubles the print time, but, it's worth it for a strong part. Will be using it soon, so we'll see how it goes.