Magura Brake info...

General
1

I have seen several Magura brakes mounted on their uni’s. I have a couple
questions:

  1. where can I find the handle type part that I have seen on the end of the
    brake lever to make is easy to brake with your hand close to the seat handle.
    It looks like a tiny bar end.

  2. any tips or is there a FAQ on the proper alignment/adjustment of the
    brakes? (I did check the Magura website, but could only find schematics of
    the hardware)

  3. any tips on shortening the tube that runs from the brake lever to the brake?

Thanks, Bronson

2

Re: Magura Brake info…

Hydraulics (ie. Maguras) are definately the best type of brake for unicycles
(better modulation, and no chance of accidently activating the brake with your
knees). Regarding the questions:

> 1) where can I find the handle type part that I have seen on the end of the
> brake lever to make is easy to brake with your hand close to the seat
> handle. It looks like a tiny bar end.

These are a fairly standard mountain biking accessory called a “dually lever”. I
may have the spelling wrong. They are sold as lever attachments for use with bar
ends. You need to cut them shorter so that they fit properly under the seat-
mine is about 1" long.

>
> 2) any tips or is there a FAQ on the proper alignment/adjustment of the
> brakes? (I did check the Magura website, but could only find schematics of
> the hardware)
>
Maguras are fiddly- there is no way around that! Mainly, I’d adjust the brakes
by first positioning the housing correctly, then using a wrench to twist the
aluminum bar into position. Make sure you are using a brake booster (the
U-shaped thing that goes over the tire)- it is the only thing that prevents the
brakes from being knocked inwards if you bang them with your knees. Magura brand
boosters work with up to 2.7" tires but it is a close fit. One tip: the standard
setup is to have a quick release on one side of the brake, and a brake booster
that is secured only on one side (the opposite side of the booster slips over a
nut without being securely attached to it. With this setup I always had problems
with the booster bending and coming loose. Eventually I secured the booster on
both sides (using a washer on the unsecured side), and it hasn’t been a problem
since then.

> 3) any tips on shortening the tube that runs from the brake lever to the
> brake?
>

To shorten the tube you need to purchase something called an “olive” from a
Magura dealer. This is a small piece that clamps over the end of the housing,
and seals the junction between the tubing and the place where the tube screws
into the brake lever or brake housing. Once you have this you can cut the tubing
to length, slip the nut (that attaches the tube to the lever or brake housing)
over the tube, clamp an olive on the end, and then reassemble.

You will now have to bleed the air out of the brakes. Be careful what brake
fluid you use! Hayes hydraulic fluid or other “normal” hydraulic fluids will
wreck Maguras. Magura fluid obviously works, but it is really just light mineral
oil sold in an expensive package. Go get light mineral oil from your drugstore.

To bleed the brakes you need a squeeze bottle with a small top on which you can
fit a 3" long, 5mm rubber tube, and a second short tube of similar diameter.
Unscrew the second hole in the brake housing and brake lever. Fill the squeeze
bottle with oil, and stuff the tube in the brake housing hole. Make sure the
brake lever is higher than the housing, so bubbles can get out. Stuff the second
tube into the brake lever hole (if you have a standard kit it screws into the
hole) and start squeezing the squeeze tube until oil comes out the top. Have the
end of the upper tube in a small glass of oil so that no bubbles can get back
into the brakeline (this is way easier as a 2 person job!). Fully depress and
wiggle the brake lever to get bubbles out of the unit. When no bubbles are
coming out, keeping the upper tube in the brake lever hole, take the squeeze
tube out and quickly put back the screw plug. Then pull out the other tube and
replace the plug there. You’re finished!

If you did a good job there should be zero delay between compressing the lever
and activation of the brake pads. If there is a delay (ie soft braking), there
is still air in the line.

Two more tips:

  1. Make sure the brake adjuster on the lever is near the middle of its range
    before you bleed the brakes.

  2. If you want to vary the position of the lever when it is not being used (ie
    bring it closer to the seat so that it is easier to grab), there is a tiny
    Allen key screw right by the bottom of the lever that adjusts it. It is a
    very short screw and provides limited adjustment. If necessary, you should be
    able to find a similar but longer screw at an industrial supply shop that
    sells metric equipment.

Hope this helps,

-Kris Holm.

> Thanks, Bronson
>
>
>

Do You Yahoo!? Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com

3

Re: Magura Brake info…

So what’s better to go with, disk or rim brakes? Does anyone have pictures of
how you fit a disk to a unicycle hub? I’m mostly concerned with having to keep a
rim true with rim brakes. I just bought a no longer in production Mavic 121 DH
rim, and both days I’ve ridden it I’ve had to true it again when I got home. The
guys at the bike shop say I should have used some heavier spokes ( 14/15 ga
double butted were used.) I haven’t broken any of them, but I think I’m
stretching them permanently. Does anyone has suggestions on keeping rims true
(short of “taking it easy”?)

Chris Reeder

Kris Holm wrote:

> Hydraulics (ie. Maguras) are definately the best type of brake for unicycles
> (better modulation, and no chance of accidently activating the brake with
> your knees).

4

Re: Magura Brake info…

Chris,

    I've set my MUni up with a CODA full hydraulic disk brake. I also have
    pictures of it. Send me a SASE to the address below and I'll send you
    the pictures. The brake has worked out very well. It was not easy making
    the custom parts required to install it on a unicycle though.

“The Muniac” 3-C Great Meadow Ln. East Hanover, NJ 07936

5

Re: Magura Brake info…

Although not intuitively obvious, the spokes are at their highest stress at
rest, not on the trail. The spokes are, in essence, a preloaded column that
undergoes less tension when weight is applied, not more. (Most people think, as
I once did, that the hub hangs from the upper spokes but it is really supported
by the lower spokes!) For the most part, the rim fails when the lower spokes
loose their preload to the point where they no longer have tension and can’t
support the rim.

It is therefore critical to tension the spokes as high as possible (to the point
of deflecting the rim and then backing off slightly) and to stress relieve them
on the truing stand (not on the trail). This will eliminate your problems. (Note
that all of this can be read in Jobst Brandt’s “The Bicycle Wheel” and has been
discussed ad nauseam over in rbt.)

If the guys at the bike shop don’t agree or understand, go to a place that does.
Really. Jim

Chris Reeder wrote:
>
> (snip) I’m mostly concerned with having to keep a rim true with rim brakes. I
> just bought a no longer in production Mavic 121 DH rim, and both days I’ve
> ridden it I’ve had to true it again when I got home. The guys at the bike shop
> say I should have used some heavier spokes ( 14/15 ga double butted were
> used.) I haven’t broken any of them, but I think I’m stretching them
> permanently.