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

New: Take part in the June Giveaway for NAKTO Camel e-bike worth $739


Replacing old cottered cranks/bb
#1
trying to replace the bb and cottered cranks on an old murray road bike (early-mid 80s is my best guess on date) - i want to replace them with modern parts (square-taper spindle and cranks). took the bb off and measured it, and it's something like 78 x 149mm (78mm being the length from outside of one cup to the other, 149 being length of the spindle). this seems really weird... am i measuring it wrong? if it's right, can i use a normal 68 x whatever bottom bracket (i'd assume not, but)? how do i size it? or do i have to track down a bb of the same size? thanks!
  Reply
#2
I really can't answer this one, but I am intrigued on how you got the cotters out though?
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#3
BP - pictures please !!! Ignore the overall length - it will have to match up with the new crankset you get. Remove the existing stuff from the frame (cups, axle, etc) the measure the housing on the frame.

Hi Bill - I always used a center punch and hammer after removing the nut and washer.
Nigel
  Reply
#4
(02-25-2012, 09:16 PM)nfmisso Wrote:  BP - pictures please !!! Ignore the overall length - it will have to match up with the new crankset you get. Remove the existing stuff from the frame (cups, axle, etc) the measure the housing on the frame.

Hi Bill - I always used a center punch and hammer after removing the nut and washer.

Hi my friend. I have a couple of older bikes ,as everyone here knows lol, that have the cottered cranks. Hammer and punch is a way to do it with a block just under the spindle on the side of the cotter that is being driven out. I use this neat little tool... http://www.bikesmithdesign.com/CotterPress/index.html .

Sorry didn't mean to high jack the thread.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#5
Bill - you are the Nut on the threaded end of a 9 mm cotter. Smile
Wheelies don't pop themselves. (from a QBP fortune cookie)
  Reply
#6
LMAO!!!! Your the cap at the end of the bar tape keeping everything smooth and together in a neatly fashioned lol.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply


Possibly Related Threads...

Forum Jump:

[-]
10 Latest Posts
Rode my First Double Century in June
Today 10:50 AM
ZULIANI Oria 'helical' tubing 80s
Yesterday 05:03 AM
NAKTO Giveaway June 2022
06-28-2022 03:52 AM
NAKTO GIVEAWAY
06-28-2022 12:16 AM
2022 road cycling season
06-27-2022 02:31 PM
OnGuard K9 Folding Plate Lock
06-27-2022 10:38 AM
Bike for commuters
06-27-2022 05:50 AM
Rim replacement for Old Cosmos SuperCors...
06-26-2022 11:24 PM
What was your first bicycle?
06-26-2022 07:18 PM
Identification help
06-25-2022 08:19 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
19 posts
no avatar 2. Yevhen
9 posts
no avatar 3. ReapThaWhirlwind
8 posts
no avatar 4. Munich Transfers
7 posts
no avatar 5. Hoodoo Creek
7 posts