Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 12-28-07, 06:48 PM   #1
StephenH
Uber Goober
Thread Starter
 
StephenH's Avatar
 
Join Date: Sep 2007
Location: Dallas area, Texas
Bikes:
Posts: 11,286
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 21 Post(s)
Cottered Crank

If you hand-fit a cottered crank together, how much farther will the pin move when fully installed?
In other words, how do you know if you need to file it down any without driving it in, then back out, then repeat, etc?
StephenH is offline   Reply With Quote
Old 12-28-07, 07:33 PM   #2
tellyho
Your mom
 
Join Date: Aug 2006
Bikes:
Posts: 2,541
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It should not move too much more. I've learned this the hard way. Pre-fit should be nearly where it sits when finally seated. Of course, someone who's done more of them is probably going to contradict me.
tellyho is offline   Reply With Quote
Old 12-29-07, 02:50 PM   #3
thechamp
loser
 
Join Date: Jan 2005
Location: portland, or
Bikes: steyr, lejeune, schwinn, sears, crescent, blah blah blah.
Posts: 385
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
sheldon brown suggests that tightening the nut won't get it tight enough.

go here and scroll down.

Good luck!
thechamp is offline   Reply With Quote
Old 12-29-07, 03:08 PM   #4
OLDYELLR
My bikes became Vintage
 
OLDYELLR's Avatar
 
Join Date: Aug 2005
Location: Ontario, Canada
Bikes:
Posts: 1,110
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
You have to hammer it (or use a press) before tightening the nut. If you have cottered cranks, it's good to have a good supply of these cotter pins (just like the other cotter pins [split pins in British parlance], they're expendable).
OLDYELLR is offline   Reply With Quote
Old 12-29-07, 09:01 PM   #5
StephenH
Uber Goober
Thread Starter
 
StephenH's Avatar
 
Join Date: Sep 2007
Location: Dallas area, Texas
Bikes:
Posts: 11,286
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 21 Post(s)
Thanks, y'all.

I had read the Sheldon Brown articles, otherwise it wouldn't have occurred to me that they might need to be filed- I would have just assumed they had to go in far enough to get the nut on. (Right now, with hand assembly, you can't even start the nut on the threads, so unless they move a good 1/4", the nut won't be fully on.)
StephenH is offline   Reply With Quote
Old 12-29-07, 10:56 PM   #6
twobikes
Healthy and active
 
twobikes's Avatar
 
Join Date: Mar 2007
Location: Caldwell, Idaho USA
Bikes: mid-60's Dunelt 10-speed, Specialized Allez Sport Tripple, Trek 7.2 FX
Posts: 887
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Cotters were once cheap and ubiquitous, but now are hard to find locally. I needed a new one, but did not have any and did not want to wait until I could get some by mail order. The threads were stripped on an old one. I cut off the threaded portion and welded a 1/4" x 20 thd/inch stud to the body of the old cotter. It worked very well. I now have more than 1,000 miles on that welded cotter with no problems. If you have access to a welder, it is also possible to build up the flat surface on a cotter and file or grind it to a new configuration.
twobikes is offline   Reply With Quote
Old 12-30-07, 03:49 AM   #7
relyt
Senior Member
 
Join Date: Jan 2004
Bikes:
Posts: 619
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Where do you mail order your cotters from? I haven't had any luck finding any and I might need some soon.
relyt is offline   Reply With Quote
Old 12-30-07, 09:11 AM   #8
twobikes
Healthy and active
 
twobikes's Avatar
 
Join Date: Mar 2007
Location: Caldwell, Idaho USA
Bikes: mid-60's Dunelt 10-speed, Specialized Allez Sport Tripple, Trek 7.2 FX
Posts: 887
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
You can get them from Harris Cyclery in West Newton, Massachusetts, which is where Sheldon Brown is based. Here is a link to their page on cotters. You probably want the 9.5 mm (3/8") size.
twobikes is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 04:56 PM.