Need help installing sealed bottom bracket on 47 CWC bike

[ratina]

I'm building a klunker out of a 1947 CWC bike and I need some help. I spent hours researching this and still got it wrong I guess. Besides the spindle length being a hair too short, the (I forget the proper term) cup that goes on the left side to stablilize the BB only screws in half way, like the BB is a little too long. What am I doing wrong? I've seen a lot of people do this, but they never list the size of the BB they use. Does anyone know? Thanks

I bought this bottom bracket: Shimano BB-UN55 68x122.5 http://www.amazon.com/gp/product/B005DTIEZQ?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s01

And this converter: Truvativ American-To-Euro Bmx Adapter http://www.amazon.com/gp/product/B000VT550K?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s01

 

[Iverider]

American Bottom Bracket (BB) shells on cruisers are narrower than Euro BBs. I would just center it up as best you can and tighten everything down. You might put the chainring and crankarm on it to check your chainline with your rear hub. Periodically check your BB for any loosening. The other thing you could do is put some spacers between the converter and the Euro bb. These are available for using 73mm bbs in 68mm bb shells. At least that will give the edge of the Euro BB something to seat against.

 

[Dale Alan]

How wide is your BB shell ? Did the adapter snug up with no problems,bolts not too long ? Did you try threading the BB cup into the adapter with the BB installed ? I know I am not much help,just starting with the simple things.I have done this many times without a problem,maybe I just got lucky.

 

[ratina]

From what I read online, all American BB's are 68mm. Maybe I was wrong. The adaptor fit perfectly with no issues. Yes, either way I install it, one side only tightens up half way.

 

[Dale Alan]

Could they have sent you a 70 or 73mm BB ? Can you feel the cup make contact and then bottom out against the BB ?

 

[Dale Alan]

I could not get a good pic without digging the bike out,this gives you an idea though.This is the same adapter,and a 68mm Shimano BB.

 

[Iverider]

The Bottom bracket will have a 73 on the sticker on the barrel of it if it is a 73. If this is the case, just buy the spacers and you should be all set. The important spacer is behind the drive side fixed cup. it may not be possible to put a spacer behind the non-drive side as many of those cups don't have a lip on them. Be sure you put the adapter in the right way as well. I know someone who put it in backwards and the bottom bracket loosed up all the time.

 

[ratina]

I double checked, and it is marked 68. I measured the width of the BB shell on the bike, and it is exactly 2.5" without the cups, which converts to 63.5mm. Was I supposed to measure with the cups in?

 

[Dale Alan]

I double checked, and it is marked 68. I measured the width of the BB shell on the bike, and it is exactly 2.5" without the cups, which converts to 63.5mm. Was I supposed to measure with the cups in?

Looks like that is your problem,you will need shims.Like mentioned above,getting the chainline correct is important .Good luck with your project,shims should be an easy fix.

 

[detroitbike]

Don't screw in one side all the way. Put in the cartridge Almost tight then screw in the
cup 1/2 - 3/4 way. Now tighten down the cartridge flush and tighten the cup flush but not tight.
Finish by tightening the cartridge snug and lastly the cup.