A 2-part bike spoke guard so you don’t have to remove your cassette to install it
My old spoke guard (aka dork disc or dork disk, though I dislike that name) cracked after years of use, so I decided to try to print my own. You don’t absolutely need one, but I’ve gotten my chain caught between the cassette and spokes (once ever) enough to prefer one.
The nice thing about this spoke protector is that it prints in 2 halves so that you don’t need to remove your bike’s cassette to install it. It’s still a little tricky to fit the guard behind the cassette though. You will need to print 2 of the included STL.
Two small 2.5mm wide zip ties hold the halves together. There are additional holes for attaching to spokes, but I don’t recommend it, as that will warp the spoke guard and might cause rubbing when coasting.
How to install the bike spoke protector
To install, I recommend loosely attaching 1 zip tie to connect the two halves. Slide the bike spoke guard behind the cassette and make sure the tabs engage with the flange of your bicycle’s rear hub.
When you’ve got it seated well, then feed another zip tie in to finish connecting the two halves of the spoke protector. This part is a little annoying, but I guess it’s less annoying than taking the entire cassette off. Tighten the zip ties and cut off the excess. It may help to pre-bend the tip of the zip tie so that you can more easily work it into the other hole.
Do you really need a spoke guard for your bike wheel?
The purpose of the bike spoke protector is to protect your the spokes of your rear wheel from damage. This can happen if your chain somehow shifts beyond the largest cog on the cassette. If your limit screws are adjusted properly, this is not an issue. I thought I didn’t need one until one time I shifted past the biggest ring got the chain stuck between the cassette and the spokes. I was moving at a fairly high speed at the time. The chain wrapped around the wheel, my wheel locked up, and luckily I was able to pull over to the curb to see what happened. The chain was wedged in really well and I had to walk home. Once I got the chain out, I had to replace two spokes because they were too damaged to continue using.
After this, I decided that I’d be ok using a spoke guard for my bike wheel.
Of course, you may not want one either. They add a bit of extra weight to your bike, and as the “dork disk” name implies, they might not look as cool. There are a bunch of videos out there that show you how to remove one. And sometimes when they break, they make annoying noises.
Spoke guard measurements and specifications
Not sure if this works well for mountain road or kids bikes – I just measured the old spoke guard and made this one to similar dimensions.
The inner hole diameter is 61mm but this spoke protector is designed for about a 54mm hub flange. The tabs extend to 51.5mm, so a hub flange somewhere in between 52.5-54mm would probably be okay. The outside diameter is 155mm.
You will need to 3D print this with supports. I think I used 50% gyroid infill with 3 walls.
This is a work in progress My chain rubs a bit when my bike is on the lowest gear, but this works better than what I had before.