I’ve been trolling around on the Observed Trials forum for a while, and someone put up a way to mount a brake directly to the Magura bosses. I went to the hardware store and about $4.00 later I had everything I needed to put my v-brakes onto my Nightrider.
Here are some pix but the idea is to get 30mm bolts that thread into the existing mounts. I put aluminum spacers in to take up the space between the bolt and the brass bushing in the caliper, and I made a plate that holds the spring out of some aluminum angle I had laying around. For more pix go to my gallery.
My V-Brakes have a small pin that keeps tension on the return springs. That pin needs to be held in a static position in order to work, and that is what the angle does (the little hole is where the pin goes). I know that there are brakes that don’t have a pin, and would work without the plate, but I would probably use a washer anyway just so that there is a clean surface for the spring mechanism to sit against.
My brake doesn’t squeal nearly as badly as it did when I had HS33’s on this uni, and I feel like the brake has better modulation. Another bonus is that these brakes don’t sit as far out from the frame. I would occasionally brush the maggies with my leg as I was pedaling through a turn. It seems like that is a thing of the past.
Thanks for the idea - I’m toying with the idea of putting a brake on my new 29, but can’t justify the expense of Maguras.
Question: does the aluminum bracket rub against the side of your frame, and have you put any buffer in between to avoid scratching the paint? Also, would this work to support the spring if you just used a flat piece of aluminum or a washer with an extra little hole, rather than the L bracket?
the angle does touch the frame, and it wouldn’t be a bad idea to pad it with a little bit of old inner tube or something. It really doesn’t move once it’s all tightened down though so not rubbing.
A flat washer may work if you can tighten the bolt enough so that it doesn’t move. Some v brakes have an adjustable nut that the spring attaches to, and doesn’t require the hole for the pin. In that case you certainly wouldn’t need more than a washer.
I had my v’s on my 29’er with a DNA adapter, and they had maybe 6+ millimeters of clearance over my 2.35 Big Apple. My V’s are the Tektro’s with fender clearance, and they might have more clearance than most others.
From a thread on a 2-wheel forum, it sounds like Shimano Deore V-brakes might work:
“From the specs I can gather: Tektro sells direct pull brakes with 102mm arms. Shimano sells “longer” arm v-brakes at 107mm.”
“My Surly 1x1 came with a set of Shimano Deore XT’s. It originally had 26x2.35” knobbies,and cleared them fine." http://www.bikeforums.net/archive/index.php/t-275163.html
Has anyone tried these type of v-brakes with any of the 29 muni tires?
The one advantage of the commercial setup is that you’re using both frame bolts, which will increase the stiffness of the braking system. Using just one bolt, the aluminum adapter will tend to want to rotate/flex with braking forces. But it probably works well enough for our needs; our braking forces are pretty minor, it’s not like we’re trying to stop a downhill bike.
That’s exactly what I was thinking. I found the original beta on the observedtrials.net forum, and someone was using this basic setup for a trials rear brake with a booster. I think in that capacity you would want a much more solid connection, but for a uni it seems to work fine.
jtrops, this is a GREAT idea! I need a new brake on my KH Geared 36. I am not happy with maguras (I gave them a try again), and I previously was using a regular old kid’s cable brake. I started machining a simple tube to go with an approach like what you did, but I think I may restart and make a single bracket thing that works better.
You can’t just increase the length of V-brake arms. With longer arms they’ll require greater lever pull for a given amount of pad movement (the whole thing’s a big lever, after all). You also have the issue of the arm itself contacting the tire. It might be possible to hack something up, but there’s a reason downhill bikes all went to disc brakes.
I just picked up a Shimano Acera V-brake. Was looking for used, but the used bike shop says they’re so cheap new that they don’t bother to carry them used. $14 new. These have a “107mm Arch” and are labeled as “Better Clearance with Mud Guard.” The arms do measure at about 107mm.
We’ll see. . .
i have a koxx-one white widow trials unicycle - i do some quite serious trials, would it be worth putting a brake on it? if so… anybody wanna show me how to fasten them on without anything to fasten them onto XD