Bicycle Disc Brake Rotor Guard

About

To protect disc brake rotors on bicycle wheels during transport I designed these covers that fit into a through axle hub and fit over the rotor. They are useful to keep things from bumping into the rotor and bending or contaminating it when the wheel is transported off of the bike, such as in the back of a car or in a wheel or bike bag.

This has been tested across a range of Industry Nine , DT Swiss , Roval , and WTB hubs and fits securely, but not so tight that the end caps get pulled out when they are removed. The large thumb holes make it easy to remove the cover with one hand, even when wearing gloves, and finger detent on the back side to help orient the cover during installation.

How To Print

I've printed these in PETG on a Bambu Lab P1S with the stock 0.4mm nozzle using Bambu Studio's 0.12mm High Quality profile (with 100% infill) because I like the smooth finish and it worked out great. The pictured examples were printed this way using VOXEL PETG+ in Grey .

I do not recommend using PLA as in my testing the decreased layer adhesion resulted in a weaker product, and in one case with the center post breaking off and getting stuck in a hub. It's also less tolerant of heat, which won't work well if the cover is used in a hot car. If you try this and it works for you, please let me know in the comments, but I will be sticking with PETG.

As suggested by a friend, a harder TPU (such as Bambu Labs' 60A TPU for AMS ) may also work quite well for this, but I haven't tested it myself.How To Print

Which One Should I Print?

Pick the size that fits your through axle (TA), the size that'll fit your rotor, and there you go. You can use a cover that's larger than needed, so if you print a cover to fit the largest rotor you have then it'll work for smaller rotors as well. There are also 15mm axle files with an extra 0.1mm of spline length, as I find some 15mm hubs to fit better with this extra diameter.

The 12mm through TA covers fit most road and gravel wheels (front and rear) and the rear wheels of most modern mountain bikes. The 15mm TA covers fit most mountain bike front wheels and select gravel bikes.

For example, I mostly use these for front wheels when the bikes are in the car, so I have 12+0x160 covers for my road/gravel front wheels (which have 160mm front rotors) and 15+1x203 covers for our MTBs (which have a mix of 180mm and 203mm front rotors).

(If you have QR / quick release wheels… Sorry. These won't work for you. But you're welcome to modify the design to make one that will.)

Files

I've provided .STEP files for all the common front and rear rotor and wheel sizes, a Bambu Studio .3MF with a plate for each of these, and the original parametric Fusion 3D file. I chose STEP instead of STL as, even at default settings in Bambu Studio or OrcaSlicer , it results in a markedly smoother (better looking, less faceted) outer perimeter. The parametric file allows for easily modifying the design.

Filenames include the axle size, rotor size, and version. For example:

- 15+1x203v3.step : 15mm through axle, 0.1mm additional spline, 203mm rotor (maximum), and v3 of the file. - 12+0x160v3.step : 12mm through axle, 0mm additional spline, 160mm rotor, and v3 of the file. (Versions 1 and 2 were development iterations, this v3 is the first to be released.)

Parametric Fusion 3D (.f3d) File

Also included is a parametric Fusion 3D file for those who wish to generate their own guards. Adjust the parameters diameterAxle and diameterRotor to adjust the main parameters for axle and rotor size, and if you need to change the depth of the guard adjust depthShell . (The default 25mm works for front and rear wheels, but this can be changed to 15mm if you want something smaller for front wheels; this depth won't cover a rear rotor.)

If you find the through axle fit too tight (or loose) then try adjusting lengthSpline . After some experimentation I settled on having the splines be the axle diameter ( lengthSpline=0 , resulting in 12mm or 15mm), with the axle itself being slightly undersized (0.2mm is removed from diameterAxle to make the non-splined part) for most hubs. To handle some slightly looser 15mm TA hubs I used lengthSpline=0.1 to make the +1 files.

Inspiration / Similar Products

This model was inspired by a few other disc brake rotor covers out there, but none were quite what I wanted, so I designed this one to learn a bit more about CAD, product design, and 3D printing.

Here's a listing of other, similar items/products and what I'm addressing with my design:

- Arch Design Works Rotor Protect : Nice product from a local company, but I wanted to something that would also cover the edge of the rotor, bowl-shaped and had a one-piece center. - Orucase Disc Rotor Protector Set : Very solid bolt-on design, probably great for when flying with a bike, but I wanted a one-handed operation. Also doesn't cover the edge of the rotor. - Muc-Off Disc Brake Cover : A nice soft cover for when cleaning or transporting bikes, but I wanted something solid and I didn't need it to keep out spray.