calculating V brake mount location
Rick Moll
braze on mounts for V brakes. I assume there is an industry
standard for locating them.
What is the standard length of a V brake arm (pivot point
to pad), it must be around 30 mm or so?
Given that there is a standard length for the brake arm,
the location of the mount (from the center of the wheel
axle) would be:
mount_point = (wheel_diam / 2) - arm_length
Assuming the arm_length is 30 mm, then for a standard
26" (559 mm) wheel the mount_point would be:
mount_point = (559 / 2) - 30
so,
mount_point = 250 mm
Can someone verify this, or give me a better formula
for determining a V brake mount point.
Thanks,
Rick
Sheldon Brown
>
> Can someone tell me the way to calculate the location of
> braze on mounts for V brakes. I assume there is an industry
> standard for locating them.
I rather doubt that.
In selecting the optimal mounting point, the width of the frame/fork and
rim should be considered.
I generally install the canti to be used on one of the studs, and hold
the stud up against the stay, moving it as necessary until I find the
position that looks best. I then mark the spot with a marker.
I have a home-made fixture for brazing canti studs. There are pictures
and an article on this at:
http://www.sheldonbrown.com/cantilever_fixture.html
Sheldon "Empiricist" Brown
Newtonville, Massachusetts
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Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772, 617-244-1040 FAX 617-244-1041
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Hard-to-find parts shipped Worldwide
Mark Hickey
>Can someone tell me the way to calculate the location of
>braze on mounts for V brakes. I assume there is an industry
>standard for locating them.
According to Shimano literature...
There are two measurements....
First is the distance between the hub axle center and the brake boss
center.
The second is the height of the brake boss from the hub axle center.
For MTB frames using 26" (ISO 559) wheels
253.5 +-1mm
For 700c (ISO622) wheels,
283mm +- 1mm, and between
For frames using 27" (ISO 630) wheels,
286 +-1mm
The "second dimension" for all is greater or equal to -8mm, and less
than or equal to 70mm.
>What is the standard length of a V brake arm (pivot point
>to pad), it must be around 30 mm or so?
Standard? In this industry? It is to laugh....
>Given that there is a standard length for the brake arm,
>the location of the mount (from the center of the wheel
>axle) would be:
>
> mount_point = (wheel_diam / 2) - arm_length
>
>Assuming the arm_length is 30 mm, then for a standard
>26" (559 mm) wheel the mount_point would be:
>
> mount_point = (559 / 2) - 30
>
>so,
>
> mount_point = 250 mm
You came out pretty close. Congrats.
Mark Hickey
Habanero Cycles
http://www.cynetfl.com/habanero/
Home of the $695 ti frame
M. Gerritsen
>
>Can someone tell me the way to calculate the location of
>braze on mounts for V brakes. I assume there is an industry
>standard for locating them.
>
>to pad), it must be around 30 mm or so?
>
>the location of the mount (from the center of the wheel
>axle) would be:
>
> mount_point = (wheel_diam / 2) - arm_length
>
>Assuming the arm_length is 30 mm, then for a standard
>26" (559 mm) wheel the mount_point would be:
>
> mount_point = (559 / 2) - 30
>
>so,
>
> mount_point = 250 mm
>
>for determining a V brake mount point.
>
However with very small wheels and/or large fork offsets it is best to
check.
Stud spacing center to center should be 44-54 mm plus rimwidth
/Marten