MacRide Spacer Threadless MTB / Gravel / Urban

MacRide (or Mac Ride) Seat 10mm thk Spacer model for 1-1/8 steer tube. Printed in Easy PA or PET-CF (prints like PETG!), 100% infill, tree supports, 3+ walls, Iron All Solid Layers. Save yourself 22$ USD for shipping a new one. 
 

UPDATE 2025/07/03

Holy crap this is the gift that keeps on giving. So, my 45 deg parts cracked trying to clean them up for the install. So 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.

Recommend materials:
Fiberon PET-CF - currently ~$50 USD/kg

• printed 10mm version but 20mm would be better for strength
• seemingly weaker layer adhesion than Easy PA. 

SUNLU Easy PA - currently ~$35 USD/kg

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

OrcaSlicer File added, again.

UPDATE 2025/06/01

I uploaded an Orca Slicer .3mf for A1 Mini, where it orients the spacer at a 45 deg angle. Still 0.18 layer height, 0.6 nozz, 100% infill, 3 walls (or more), concentric EVERYTHING and ARACHNE wall generation. Spacer looks a heck of a lot better and is much stronger. I spent probably 6 or 7 test prints worth of filament dialing in these settings. The key is having continuous layers bridge across the Z direction so they can flex and not crack the spacer. As CNC kitchen showed, printing at 45 deg is a magical trick that FDM printers can handle and reduce layer adhesion issues in multiple directions.

Uploaded images with critical slicer settings. Uses more filament but reduces post processing and more importantly, orients the layers in a direction such that the groove ledges won't crack. 

Using this method of slicing, the supports peel right off.

UPDATE:

I experienced a layer adhesion failure (duh) from having all concentric layers, and the spacer laying flat. The groove “shelves“ sheared off. So, my next prints will be to orient the spacer vertically. I wasn't sure if the material would be strong enough in the Z but it appears not. Anyway, orienting the part at an angle or vertically will definitely increase Layer strength in the Z (steerer) direction. 
 

Printing

See latest update for Orca Slicer file.

I clearcoated mine to avoid carbon fibers in my skin or the environment. We'll see how long it lasts. 

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