Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take Part in the May Giveaway for a Change to Win the Thruster 27.5 Retrograde BMX Cruiser Bike


Bottom Bracket upgrade from a one-piece crank?
#1
I know this question has been asked a million times, so I will add another to the count Wink

The bottom bracket as seen in the attached pic is of a CCM (Canadian brand) entry level bike from the 80's. The diameter of the shell is 2 inches, roughly 50 mm. There are no threads.

From what I've read, it appears that I need an adapter kit to fit another type of bottom bracket? What are my options? Are there any advantages?

Thanks in advance.
  Reply
#2
You would need the adapter, a new bottom bracket, new crank, and new pedals.
The conversion will shave some weight off the bike, look a bit cooler, and give you more choice of crank/pedals, especially if you're trying to get gearing set ups you can't get with a one piece. But the bike won't really perform much differently.

Whether it's "worth it" or not, I can't say. If the bike has steel rims, upgrading to decent quality aluminum wheels will likely make a much bigger difference in how it rides.
  Reply
#3
My main concern is understanding how to measure or select an adapter kit suitable for this shell and whether it limits choices for the type of bottom bracket I would have to install.

Thanks for the note regarding rims, I haven't given it much thought beyond wanting to upgrade them as well. The current steel rims are cheap - spots of chrome is removed and there are stress lines along the nipple holes.
  Reply
#4
This is your cheapest alternative:
http://www.amazon.com/Pyramid-Piece-Bottom-Bracket-Conversion/dp/B000AO9O12/

but as one of the reviewers suggested, spend a bit more and use a cartridge BB:
http://www.amazon.com/BB-Conversion-Bp-American-To-Euro/dp/B001G8TSPS/
Nigel
  Reply
#5
Sweet, thanks Nigel!
  Reply
#6
Does he have to check that the BB opening is 68mm wide? His frame looks like it has a recessed "lip" area around the BB opening. Won't the adapter have a gap between the back of it's flanges and that frame area?
[Image: attachment.php?thumbnail=3905][Image: 412AkhfrdDL._SS500_.jpg]
  Reply


Possibly Related Threads...

Forum Jump:

[-]
10 Latest Posts
Specialized bicycle post issue
Today 04:30 PM
Expensive bikes with crappy wheels
Yesterday 08:58 AM
Philodo H8
Yesterday 08:57 AM
ISO Susan B bike by Terry
05-25-2024 10:46 PM
9 speed chain on 8 speed bike
05-25-2024 10:24 PM
Shimano Deore shifter
05-25-2024 02:09 AM
What did your first bicycle mean to you?
05-23-2024 11:38 AM
Doctors are Prescribing Cycling
05-23-2024 11:34 AM
Getting back into riding, bike instead o...
05-22-2024 12:55 AM
What was your first bicycle?
05-21-2024 07:27 PM

[-]
Join BikeRide on Strava
Feel free to join if you are on Strava: www.strava.com/clubs/bikeridecom

[-]
Top 5 Posters This Month
no avatar 1. Jesper
35 posts
no avatar 2. Nutribun
22 posts
no avatar 3. enkei
19 posts
no avatar 4. Burrobabe
14 posts
no avatar 5. GirishH
13 posts