Bottom Bracket Shims?
04-15-17, 04:15 PM
#1
Cantankerous Old Fart
Thread Starter
Join Date: Mar 2010
Location: On the Tundra of Northern NY State, almost Canada eh?
Posts: 188
Bikes: TBD
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Bottom Bracket Shims?
I'm converting a 3 piece BSA type bottom bracket to a cartridge. In order for the 68 x 122.5 BB I'm using to have the same chainring clearance as the 3N spindle, I need to offset the BB by at least 1.5mm.
The only shims I have been able to find that list the actual ID and less importantly, OD are the "Wheels Manufacturing" spacers and they seem a bit pricey. Are the shims made by Shimano and others have the correct 1.38" ID?
The only shims I have been able to find that list the actual ID and less importantly, OD are the "Wheels Manufacturing" spacers and they seem a bit pricey. Are the shims made by Shimano and others have the correct 1.38" ID?
04-15-17, 07:54 PM
#2
Senior Member
Join Date: Feb 2014
Location: Southern Ontario
Posts: 1,883
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 263 Post(s)
Likes: 0
Liked 9 Times
in
8 Posts
Freehub and bottom bracket shims are the same size. Usually lots of different thicknesses of freehub shims available for adjusting single speed chainlines.
04-15-17, 08:14 PM
#3
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,790
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3590 Post(s)
Liked 3,401 Times
in
1,935 Posts
For the most part they are the same, anyway. BITD, we used Sturmey-Archer cog spacers for bottom bracket spacers. Modern freehub spacers are lighter (aluminum versus steel) and available in a variety of thicknesses. The only place where you might run into problems is if you need to use them with an Italian thread bottom bracket. Italian thread cups are slightly larger diameter than English thread cups, and cog/freehub spacers won't fit over them. Fortunately, the fix is easy: simply split the spacer so you can expand it slightly to fit over the cup.
04-15-17, 09:34 PM
#4
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,094
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4210 Post(s)
Liked 3,875 Times
in
2,315 Posts
The other aspect of shimming a drive side BB out that can be a problem is if the shims are so thick that the resulting off set of the BB unit requires the non drive side retaining ring to be run into the BB shell too far. If the retaining ring (some might call this a cup...) has a flange on it's outer edge, like Shimano plastic ones do, this flaired edge will not allow the ring to thread into the shell more then a certain amount. Andy
