V-brake

At 12:10 AM 4/10/99 PDT, you wrote:
>
>> It also has a seatpost shock and V-brake.
>
>What in the world is the v-brake for?

Having a V-brake is somewhat experimental. To offer any advantages it also
involves a bit of a learning curve before you stop getting pitched onto your
nose, but in my opinion these are the advantages:

  1. generally, it is a huge knee-saver on long descents
  2. extremely steep slopes and especially steep ramps or rockslopes, where leg
    strength becomes a limiting factor, are made easier (once you learn not to
    fall on your nose when you apply the brake, that is!).
  3. Descents of narrow logs are easier, because using the brake allows you to put
    more weight on your seat, which reduces wheel wobble which might send you
    careening off the log.
  4. I think that having to concentrate less on slowing down allows you to
    concentrate more on balance.
  5. Drops that end on steep slopes can be done with more control because you have
    increased stopping power.
  6. I think that it has potential to reduce axle breakage by reducing the
    pressure on the rear crank when you land off a drop.
  7. With a lot of practice, I think that gliding might be possible with the brake
    instead of having your foot on the wheel.

To install the brake lever on the MUni, the machinist welded a short tube (at
the appropriate angle) to the front of the rails that attach the seatpost to the
seat (I had rails made for my Miyata seat so that other seatposts can be used).
The brake lever clamps onto this tube. Brake lever extenders for mountain bike
bar-ends are available, which clamp onto the break lever at 90 degrees to the
lever. I cut one of these down and clamped it so that it is directly below the
handle on the front of a Miyata seat. Thus, you can grip the seat handle and
operate the brake at the same time.

Hope that wasn’t too confusing without a picture!

Cheers,

Kris At 12:10 AM 4/10/99 PDT, you wrote:
>
>> It also has a seatpost shock and V-brake.
>
>What in the world is the v-brake for?
>
>I can understand using a drag brake if you were on a touring uni going down a
>mountain pass. But a brake on a muni with 175mm cranks?
>
>Are you bombing straight down some nasty steep slopes?
>
>John “I never break” Childs john_childs@hotmail.com
>
>
>> It’s a home-brew, made by a machinist in town that makes bike prototypes.
>>
>> In short, the frame is 4130 CrMo with Miyata style bearing casings, the axle
>> is a 20mm 8 spline 4130 CrMo BMX axle braised into a one-piece custom 4140
>> steel hub, the crank arms are 175mm, the rim is a 26" Mavic SUP 36 hole
>> downhill Mtn Bike rim, and the tire is a 26"x2.35" Kujo downhill mtn bike
>> tire with foam- reinforced sidewalls (which prevents pinch-flats). It also
>> has a seatpost shock and V-brake.
>>
>> Cheers,
>>
>> Kris.
>
>
>_______________________________________________________________
>Get Free Email and Do More On The Web. Visit http://www.msn.com
>


Kris Holm, B.Sc. Geologist, Forestry Group, EBA Engineering Consultants Ltd.
Suite 550, Sun Life Plaza, 1100 Melville Street, Vancouver, B.C. V6E 4A6
Tel:(604) 685-0275 Fax:(604) 684-6241 Email: kholm@eba.ca

Re: V-brake

OK, now it makes more sense. I was thinking more in terms of x- country muni
riding and it would be very hard to justify a brake for that. But I can see now
how it would be useful for trials level riding.

#2 and #3 make a good case for using a brake. Going down a narrow
steep ramp like a log or 2x6 would be extremely difficult without a brake. It is
very difficult to ride a straight line while doing hard backpedaling.

#5 also makes a lot of sense for the kind of drops and the kind of
control you need for trials stuff. You also wouldn’t have to worry so much about
having your pedals horizontal when you land a drop.

Using a brake might also make it easier to get a good “launch” when jumping.
With the brake locking the wheel you could get more of a launch off the pedals.

Saving the knees is also a very noble cause.

And technically because you are only using one brake you can still claim to have
no brakes.

Best of luck john_childs@hotmail.com

>Having a V-brake is somewhat experimental. To offer any advantages it also
>involves a bit of a learning curve before you stop getting pitched onto your
>nose, but in my opinion these are the advantages:
>
>1) generally, it is a huge knee-saver on long descents
>2) extremely steep slopes and especially steep ramps or rockslopes, where leg
> strength becomes a limiting factor, are made easier (once you learn not to
> fall on your nose when you apply the brake, that is!).
>3) Descents of narrow logs are easier, because using the brake allows you to
> put more weight on your seat, which reduces wheel wobble which might send
> you careening off the log.
>4) I think that having to concentrate less on slowing down allows you to
> concentrate more on balance.
>5) Drops that end on steep slopes can be done with more control because you
> have increased stopping power.
>6) I think that it has potential to reduce axle breakage by reducing the
> pressure on the rear crank when you land off a drop.
>5) With a lot of practice, I think that gliding might be possible with the
> brake instead of having your foot on the wheel.
>


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Re: V-brake

Kris Holm wrote:

> At 12:10 AM 4/10/99 PDT, you wrote:
> >
> >> It also has a seatpost shock and V-brake.
> >
> >What in the world is the v-brake for?
>
> Having a V-brake is somewhat experimental. To offer any advantages it also
> involves a bit of a learning curve before you stop getting pitched onto your
> nose, but in my opinion these are the advantages:

Thanks for your superb description of the V-brake and it’s advantages. Although
I have been too lazy to fit one to my Muni (and Coker), you have spurred me on,
I really must do it. Have you thought of replacing the brake lever with an
friction gear lever from a road bike. This is what Leo White has done and it
allows you to apply controlled friction to the wheel while leaving your hands
free to hold the seat or balance with. I was very impress with both the fitting
and performance of Leo’s adaptation, I hope he will give us a fuller
description.

Cheers

Roger

Re: V-brake

Have you tried using a friction gear lever instead of a brake lever?
e.g. Shimano Bar end levers for touring bikes

I found it easier to use off-road as you just pull it on far enough to cancel
out the gradient and don’t accidently modulate the brake when bumping off rocks.

I haven’t used a brake off road since I got a “Roger Davies” frame and couldn’t
face drilling through the aluminium forged fork crown to fit my BMX caliper
brake. I’ve thought about fitting a V-brake by clamping on some bottle bosses to
the fork legs and using a ‘V-brake booster’ to make the whole affair rigid.

Has anyone else got suggestions for fitting one?

Leo White, Cheltenham

>To install the brake lever on the MUni, the machinist welded a short tube (at
>the appropriate angle) to the front of the rails that attach the seatpost to
>the seat (I had rails made for my Miyata seat so that other seatposts can be
>used). The brake lever clamps onto this tube. Brake lever extenders for
>mountain bike bar-ends are available, which clamp onto the break lever at 90
>degrees to the lever. I cut one of these down and clamped it so that it is
>directly below the handle on the front of a Miyata seat. Thus, you can grip the
>seat handle and operate the brake at the same time.
>

Re: V-brake

Re query from Roger Davies: >Have you thought of replacing the brake lever with
an friction gear lever from
>a road bike
>
I hadn’t considered this but it sounds like a good idea. I was thinking of
changing to a hydraulic brake, which is what most trials riders seem to use,
because it gives the best modulation of force. Also, with hydraulic brakes you
couldn’t accidently compress the brake with your foot, if you had one foot
against the frame because you were gliding.

Cheers,

Kris.


Kris Holm, B.Sc. Geologist, Forestry Group, EBA Engineering Consultants Ltd.
Suite 550, Sun Life Plaza, 1100 Melville Street, Vancouver, B.C. V6E 4A6
Tel:(604) 685-0275 Fax:(604) 684-6241 Email: kholm@eba.ca

RE: V-brake

I don’t have a webpage I could post a picture of it on, but I’ll try to think of
some way (maybe scan it and include as an email attachment?)

At 05:18 PM 4/12/99 +0100, you wrote:
>[sdg] Kris,
>
>where can i see a pic of this vbrake arrangement ?
>
>Simon
>


Kris Holm, B.Sc. Geologist, Forestry Group, EBA Engineering Consultants Ltd.
Suite 550, Sun Life Plaza, 1100 Melville Street, Vancouver, B.C. V6E 4A6
Tel:(604) 685-0275 Fax:(604) 684-6241 Email: kholm@eba.ca

Re: V-brake

I’ve just finished fitting a ‘V’ Brake to my Carbon Fibre Uni. (behind the fork)
This is the ingredients I used :

2 Pace Bolt on Brake Bosses intended for their 1998 range of Suspension forks 2
Bits of rubber intended for ‘D’ lock brackets 2 more slim bits of rubber 1 Avid
rear ‘V’ brake 1 Front ‘V’ noodle 1 Topeak Bottle cage holder that bolts to a
seatpost (no bottle cage) 1 Band on cable stop 1 Road Bike downtube gear lever
bolted to the Topeak thingy under the saddle

Until I can take a pic and digitise it you’ll have to use your imagination!

It seems to work okay on my driveway I haven’t fitted a brake booster yet as it
doesn’t seem to need it. It’ll get a proper off-road test this weekend - I’ll
post a report

Leo White

>At 05:18 PM 4/12/99 +0100, you wrote:
>>[sdg] Kris,
>>
>>where can i see a pic of this vbrake arrangement ?
>>
>>Simon
>>
>_______________________________________________________
>
>Kris Holm, B.Sc. Geologist, Forestry Group, EBA Engineering Consultants Ltd.
>Suite 550, Sun Life Plaza, 1100 Melville Street, Vancouver, B.C. V6E 4A6
>Tel604) 685-0275 Fax604) 684-6241 Email: kholm@eba.ca
>

Re: V-brake

>1) How did you attach the rails to the Miyata Saddle, and do they make it less
> flexy?
>
I don’t seem to have problems with flex on my seat, never have actually. I do
pull up on it quite hard so I’m not sure about this problem of yours.

>2) Do you find your saddle twists on the seatpost, the one I adapted developed
> an annoying side-to-side motion affecting the steering.
>
The rails are super thick and don’t flex at all. I have a good seatpost that
has a very strong rail clamping mechanism so this doesn’t seem to be a
problem either.

>3) I never saw the pictures posted of your race - have you got any tips for
> large drop-offs.

Yes. I think that it is very important to keep the wheel rolling. Although it is
tempting to bounce around at the lip of the drop while you are considering it
(and necessary if you are totally unsure about it), I almost always land better
if I just ride straight off. Also, when landing, I think it is better to land
with the crank arms near vertical (maybe 70 degrees to vertical) and immediately
roll into the power position (crank arms horizontal), rather than landing in the
power position, as this keeps the wheel turning and provides much more shock
absorption. If you are landing on steep ground, immediate use of the brake is
also a big help. If the drop is really big and not quite vertical, sometimes I
find it is easier to richochet the wheel off the steep (but not vertical) drop
part way down, and land the same way, or try to let your feet just roll like
crazy with your wheel touching the whole way. For the latter, a brake is
extremely useful so you can brake just at the limit of tire friction.

> Do you need to hold the saddle out to bend your knees on impact, and do you
> need to cycle in the air to bring the pedals horizontal?

I generally never bring the saddle out front for drops (see above), but often
will rotate my pedals in the air to the best landing position (also see above)

>
>4) You must be quite tall to use 175 cranks and a suspension post !
>

I’m 5 foot 11 (around 190cm), and have modified (shortened) the seatpost by
about 1/3 (CODA brand seatpost shock). It had an elastomer inside the tube,
and the tube was cut down and the elastomer replaced with a coil spring from a
pair of Manitou bike shocks. I’m considering going to a parallelogram style
seatpost shock.

Cheers,

Kris.

>Leo
>
>-----Original Message----- From: Kris Holm <kholm@eba.ca> To: Leo White
><l.white@cableinet.co.uk> Date: 17 April 1999 00:07 Subject: Re: V-brake
>
>
>>Leo,
>>
>>You might be interested: attached is a picture of the system I used to attach
>>the brake lever.
>>
>>-Kris.
>>
>>
>


Kris Holm, B.Sc. Geologist, Forestry Group, EBA Engineering Consultants Ltd.
Suite 550, Sun Life Plaza, 1100 Melville Street, Vancouver, B.C. V6E 4A6
Tel:(604) 685-0275 Fax:(604) 684-6241 Email: kholm@eba.ca