As UNIbike says, it’s not normal to put brakes on a trials uni. Trials bike riders us brakes in a very different way to unicyclists, as they aren’t able to lock the wheel as we can by just keeping the cranks still. A unicycle brake is basically just used to make a steep downhill appear shallower by putting a bit of resistance on the wheel.
If you really wanted to put brakes on, though, you would need a pair of Magura mounts either welded on or braised on, which would give you the bosses for the brakes to bolt on to. But seriously though, I wouldn’t recommend it on a 20".
Here’s the follow-up report: I basically did the same thing as jtrops, using a Shimano Acera V-brake. With a new brake and used handle, plus a little hardware store stuff and using less than 2 inches of aluminum angle (which I already had in the garage so not included in my project cost), total cost about $25. Works great, with no clearance issues.
I’m curious about whatever difference there is in the setup I’ve got vs. yours. I’ve got a 2009 KH29 with the stock 2.3" Stout tire, and no worries. The clearance for the brake is slightly bigger than the frame. In other words, a bigger tire would hit the frame before it would hit my brake.
OK, finally got arround to figuring out how to post pictures (not that it took much effort, but I’d been lazy about it), so here goes. I also considered using channel, and actually have a piece that fits over the maggie mounts perfectly. However, it didn’t leave me enough width to put in the little hole for the spring retension, so I went with the plain angle. The black on the angles is just some electrical tape to prevent rubbing, which seems to be adequate because there is no movement once it’s tightened down. The little tubes are aluminum spacers I found at the hardware store. They fit almost perfectly, although there is a tiny bit of sideways slop in the system along the length of the screw. Length of the tubes are as bought, which is just about right. I also bent out the aluminum angle pieces to better fit the contour of the weld along the maggie bracket, and prevents any rotation of the angle.
Very nice. I like the way the brake arms aren’t sticking out at all from the frame. I should probably use the electrical tape on mine now that I look at yours. For one thing it makes them look a little more finished.
Thanks. Yeah, the tape looks decent, is easy to apply, and basically doesn’t cost anything. Might need replacing over time, but then I’ve been amazed at how many years similar applications on my motorcycle have held up.
Nice job on the brake set up. From where to where do you measure the length of the arms to get 107 mm? If I can’t find the Shimano Acera I would like to be able to take of measurement for comparison. Thanks.
That was approximately center of bolt hole to center of hinge or where the cable connects. I included rulers in the photos for sizing (although I suppose they could have been lined up a little better).
I think mine is a rear brake, but not totally sure. I’m also not sure of the difference – on my old mountain bike the front and rear v-brakes look exactly the same (the noodle lead is even the same, such that they point to opposite sides when mounted on the bike).
I found out that a front or a rear brake can be used but since a front brake faces forward and a rear brake faces back the pads (which are directional) need to be on the correct side. If you use a rear brake, the pads would be in the correct position. If you use a front brake, you would need to switch the pads to the opposite side.
It should work just as well. My Nimbus 29 didn’t have brake bosses, so I used a DNA adaptor. The newer frames with the bosses should be easy enough to put a V brake on.
