Brake Boss Welding

I’m finally thinking of putting brake bosses on my MUni. It’s a hard decision because it’s so beautiful as it is, and I would hate to ruin that.
I’ve noticed that the most tiring thing for me on my rides are the downhills, and I want to reserve my strength for other parts of the ride. So I’m considering welding on brake bosses.
I’ve got a question about welding. My SHaKH NaS MUni is stainless steel, and I was told that if I wanted to weld to hold, I’d have to use like metal for the bosses as well. Is there any truth to that? Will I have to get stainless steel brake bosses? I know nothing about welding, so any help would be great.

Don’t weld on that beautiful piece of equiptment!!!
Get one of these:


I am going to propose a rule that everyone who has brakes must remove the levers before the start of the Downieville Downhill at Cal Muni Weekend. It is only fair to those who do not have them.
If I happen to install brakes before then, however, there will be no need for such a ridiculous rule.


We had a situation at work where a cast iron plug was welded to a steel tank and it never did stop cracking. The problem is the different temperature expansion rates, if you can find a material with the same coefficient of expansion, it should be ok. Although, you might have to get the same alloy stainless.

AHA! That’s right! Why penalize people for having brakes? They spent the money, went through whatever setup and adjustment hassles, and, remember, they have to carry the extra weight on all the uphills.

Downieville is a great place for brakes, but we’ll be fine without them. But the ride is on Sunday on purpose; you might be pretty tired on Monday! :smiley:

Paco - Your frame is common 300 series stainless steel. TIG welding carbon steel brake bosses (what most bike brake bosses are) to the stainless will be no problem as long as the filler rod that the welder uses is stainless steel. Filler rod is what’s melted during the welding process to fill the gap or create a fillet between the parts that are being joined together. Stainless brake bosses would be cool since they would never rust but would have to be custom made I’m sure.

Are you thinking of adding v-brake bosses or hydraulic Magura brakes? I’ve read that v-brakes don’t work well for MUni because the wide rims and tires we use make the v-brake arms stick out to get pushed and snagged on things making the brakes activate when you don’t want them to.

Steve Howard

I don’t know about you, but I’m planning on riding up the uphills! :wink:

Thanks for responding. I would have e-mailed you, but I thought this might come in handy for someone else, too.
I’m thinking of using the V-brakes. The hydraulics seem a little out of my price range, but I’m only using a 2.6" tire, so hopefully it shouldn’t be as big of a problem.
I really hope I’m doing your frame justice.

Re: Brake Boss Welding

Paco, what you want is this kit: Make sure you weld them
on as your frame-maker has described and you’ll love it. The brake you want
is - you won’t have to
use the booster with this setup so no worries with a 3" tire.

See you in Oct!


PS The no-welding solution is a very low-end piece
of equipment that you won’t like long term. Although if on an extreme budget
it could be used until the real hydraulic solution is affordable.

Hey Paco,
If you’d rather use Maguras, I have a set that I bet I can fit into your “price range”

Paco and Nathan, you guys ROCK!

I should receive my new Yuni frame tomorrow or the next day. I ordered the cheap chrome model, because I plan to have the chrome bead or sandblasted off, and a custom paint job applied.

I had a couple ideas to weld on before the paint job, but now I plan to add the Magura Braze-On Brake Kit also.

One question, how will I know where to weld the brake holders on without also having the Brake Assembly in hand at the same time. Is there a way to measure from center of the hub up, and find the exact spot? Or some other way? I am to cheap to order the brake right now too. --chirokid–

PS: K’nKenny, if Paco is not interested in the Maguras at an “affordable price”, I might be. PM me, but only after Paco makes his decision.

Re: Brake Boss Welding

> One question, how will I know where to weld the brake holders on without
> also having the Brake Assembly in hand at the same time. Is there a way
> to measure from center of the hub up, and find the exact spot? Or some
> other way? I am to cheap to order the brake right now too.

I would be too chicken to weld without KNOWING I’ve got exactly the right
spot. The kit includes the brake holders, so maybe you can convince your
friendly LBS to let you fit with a Magura brake they have in stock. But it’s
probably better to just enjoy riding for now with the stock frame, and when
ready, buy both brake and braze-on kit, weld them on and repaint if you feel
you need it. You can probably just touch up the chrome in that area a little
and get by find without repainting. If you ride in the wet all the time
though, you need the metal covered.


The center-line of the Magura specific brake mount will be the center-line of the rim with the wheel mounted in the frame. The other factor would be that they are mounted at a right angle to the rim with the flange to the inside (with the bolt holes on top).
Chirokid, place the wheel in the frame and have your welder scribe the location on the fork. A simple jig should square them up, fairly routine work for a welder. If you get a photo of a set mounted on a fork, I’m sure an experienced welder would have no problems.
If you get the mounting kit, notice that the mounts and the aluminum brackets have no designated “up or down”. The center-line will dictate location.
I’m pretty sure Darren Bedford sells the Nimbus II (Yuni) frames with the mounts already brazed on and he has them powder coated too.

i kind of like the idea of having brakes on a muni, having ridden with them for short while on a qu-ax prototype muni in germany.

but doesent the positioning of the braze ons limit your choice of rims?
or have i just never paid atention to the world of 24" rims enough? are they all much of a muchness?

the qu-ax frame had v-brake mounts and the magura brakes were fitted using the magura evolution adapters, while this looked ugly it did alow a bit of adjustability.

that said, i`ll be saving for a nimbus frame with magura mounts as soon as i return from my travels

Has anyone had any problems with the Magura Hydraulic brakes or the braze-on kit? I don’t know of too many other options (from, at least).

and one more question about the practicality of brakes,

don`t you have to realy make sure that your rim is perfectly true?,

i ride my trials unicycle with a realy bent and bashed monty rim thats currently splitting arround the spoke nipples, it is no longer posible to true it properly, if i was riding a 24 i`d have to replace the rim as soon as it became untruable,

it would be kind of iritating having to treat a bad boy 24 muni with kid gloves just so i could use the brakes,

                                                                                        I haven't had any problems with either.  I welded on a Magura brake mount kit to my Hunter.  Reminder though, figure out the rim width you will be using.  Magura recommends 90 MM spacing, I found this to not be enough (using Azonic Momentum 44MM rim) for wider rims.  My KH pro measures 98MM.  Ended up having to cut the ones off my frame an hour after I painted it.  Another recommendation, get the 90 degree kit for the hose at the lever.  You can direct the hose a little better and it will be shorter.  It is a pain to put together though.



Above two things are great. I wanted those but not reached there.
I’m currently using Mavic Deemax 26" rim and Alex 24" rim.
I have wanted to by Azonic Momentum 24" rim because it is very wide and also have good rim braking surface.
But here, they only sell as a complete wheel set which has a little bit high price tag on it. Also they have no 24" yet . I wish they
make 24" and sell as a rim only. If they do, it will be a great deal
for the municyclist.

For 90 degree connector, I have dreamed it. Not reached there.

I’d never thought of the braking surface before…
Will a Alex DX 32 give enough surface for the brakes to work? I know no one personally who has brakes on their uni, so I can’t ask anyone around here.
(edit) Never mind. I just looked on and the basic Kris Holm model comes with a Alex DX 32. So that answers my question.

Hey guys, sorry it took so long, but I finally answered the pm about the Maguras.


i am looking at the brakes for unis is it worth putting them on a trails uni? even if they are not do they make a massive difference or not???