Difference between revisions of "Shimming Eccentric Bottom Brackets"

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(The Standard)
(Reaming the Shell Round)
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===Reaming the Shell Round===
 
For the best possible fit, I will be reaming the bottom bracket shell round. I have reamed many bottoms, and I suggest grease for most.
 
  
I will use an adjustable hand reamer (MSC # 02239135) Industrial size M. This will eliminate the distorted shape and make the shell easier to shim.
 
 
The reamer is huge. OAL 410mm.
 
<br>[[Image:Bbshim4.jpg]]<br>
 
 
A 12 point socket helps drive the reamer. It may take about 50 rotations, so don't use a rickety setup.
 
 
 
<br>[[Image:Bbshim5.jpg]]<br>
 
 
The reamer requires the use of a cutting oil as well. Motor oil is fine in a pinch.
 
 
After a light cutting pass, the distortion in the shell is obvious.
 
<br>[[Image:Bbshim6.jpg]]<br>
 
  
 
===Shiming the Eccentric===
 
===Shiming the Eccentric===

Revision as of 05:57, 1 December 2006

Recently, I put together a 17" 2006 Zion 660EBB Singlespeed frame.

It has an eccentric bottom bracket with dual locking set screws.




Shiming the Eccentric

I will fill the gap using some stainess steel shim stock. It is best to use a single shim so that it is as thick as it can be for durability sake. I prefer stainless shims over brass for the same reason.

Bbshims.jpg

A 0.010" shim and a 0.0015" shim. In the end, just the 0.010" shim was used and it was a very snug fit.

The greased shim with a bend to help installation
Bbshim7.jpg


Hardware Replacement

The two round head cap screws were replaced with Stainless Steel Cap screws for use with a larger wrench and matirial to grab in a worst-case situation. Now a 5mm allen wrench can be used.



Bbshim10.jpg

Greasing and Installing

Marine Grease. Use marine grease. Its what I use when reaming bottoms.


Test fitting.
Bbshim8.jpg

I also need to find a way to rust proof the edges.
Bbshim9.jpg

Park SPA-2 tool is used to roll the cam.
Bbshim11.jpg

Proudly made in Taiwan.
Bbshim12.jpg