BB axle length for track bike?
Michael Giess
bracket for it (the old one that was installed was a 73mm MTB bottom
bracket with 116mm axle length - the wrong size in every respect!)
The shell width is 68mm but I am not sure of the axle length required.
Is there any way I can measure this or is it a case of trial and error?
Thanks for any help.
Michael
Gary Pritchard
with the manufacturer of the crank to get the correct size.
Michael Giess wrote in message <362132...@kittyhawk.aero.rmit.edu.au>...
Steve Freides
have different profiles. Although I'm far from expert in this area, I
do know that, e.g., Campy BB spindles are typically shorter than
Shimano, at least for road use.
-S-
Sheldon Brown
Michael Giess <s95...@kittyhawk.aero.rmit.edu.au> wrote:
> I just bought a track bike on the weekend and I need to get a new bottom
> bracket for it (the old one that was installed was a 73mm MTB bottom
> bracket with 116mm axle length - the wrong size in every respect!)
Yow! I'll say!
> The shell width is 68mm but I am not sure of the axle length required.
> Is there any way I can measure this or is it a case of trial and error?
Most track cranks use a 109 mm bb.
Sheldon "Pignon Fixe" Brown
Newtonville, Massachusetts
+----------------------------------------------------------+
| Injustice anywhere is a threat to justice everywhere. |
| -- Martin Luther King, Jr. |
+----------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-1040 FAX 617-244-1041
http://www.sheldonbrown.com/harris
Hard-to-find parts shipped Worldwide
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Dan Goldenberg
>bracket for it (the old one that was installed was a 73mm MTB bottom
>bracket with 116mm axle length - the wrong size in every respect!)
>
>Is there any way I can measure this or is it a case of trial and error?
>
>
>Michael
If you know how to measure chainline, do the following:
1. Measure the chainline up front with the crank installed.
2. Measure the chainline at the back cog.
3. Figure out what the difference is, if any.
4. Pick an axle length that will correct the chainline, remembering that you
need to double the axle length of the needed correction, for example, if you
need to move the front chainring in 2 mm, you will need an axle 4 mm shorter
than your existing one.
Also, measure the clearance that the chainring has with the right chainstay
to make sure that if you need a shorter axle you will not have clearance
problems.
This method would work pretty good if you had the correct 68mm bottom
bracket installed but I don't know what effect having a 73mm BB installed
will do in positioning the axle, but it should come close.
If you don't know how to measure the chainline you can do the following (you
will need some calipers):
1. For the front:
a. measure the seat tube diameter.
b. divide this measurement by 2. Call this "X"
c. measure from the edge of the seat tube to the center of the Chainring,
Call this "Y"
d. the chainline at the front is "X" + "Y"
2. For the rear:
a. Measure the rear dropout spacing.
b. Divide this measurement by 2. Call this "X"
c. Measure the distance (with hub installed) from the inside edge of the
right dropout to the track cog, call this "Y".
d. the chainline at the rear is "X" - "Y".
John Dacey
wrote:
>The cranks you're going to use make a big difference - different cranks
>have different profiles. Although I'm far from expert in this area, I
>do know that, e.g., Campy BB spindles are typically shorter than
>Shimano, at least for road use.
>
As part of our online catalog of track hardware, there's a page of
technical reference specifications, including spindle length
requirements for a variety of track cranks. The URL direct to that
page is
http://www.businesscycles.com/spokewrench/tr-refspec.htm
- - -
http://www.businesscycles.com/spokewrench
Business Cycles
9818 S.W. 77th Avenue
Miami, Florida 33156
305-273-4440
Rick Denney
cranks, which use 111 mm spindles.
Business Cycles in Miami has a good web page about track stuff, and
the page showing spindle specs is
http://www.gate.net/spokewrench/tr-refspec.htm#cranks
On Mon, 12 Oct 1998 08:34:06 +1000, Michael Giess
<s95...@kittyhawk.aero.rmit.edu.au> wrote:
>I just bought a track bike on the weekend and I need to get a new bottom
>bracket for it (the old one that was installed was a 73mm MTB bottom
>bracket with 116mm axle length - the wrong size in every respect!)
>
>The shell width is 68mm but I am not sure of the axle length required.
>Is there any way I can measure this or is it a case of trial and error?
>
>Thanks for any help.
>
>Michael
Rick Denney
Take what you want and leave the rest.
DD
going to put on a basic japanese track crank like a Sugino, you'd need a
109mm. But in any case you just need to determine what crank. Check out
www.businesscycles.com; if anyone would know they would.
Michael Giess <s95...@kittyhawk.aero.rmit.edu.au> wrote in article
<362132...@kittyhawk.aero.rmit.edu.au>...