Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

square crank - engaugment length on shaft

Notices
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.

square crank - engaugment length on shaft

Old 03-07-11, 08:44 PM
  #1  
Member
Thread Starter
 
bjohn's Avatar
 
Join Date: Oct 2009
Posts: 30
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
square crank - engaugment length on shaft

what is the correct length of crank arm to shaft engaugment, or how far should the crank arm push on to the bottom bracket shaft. I've push it on and it is 5mm away from where the washer sits (end of shaft). Its engaugment, alloy contact area to shaft is about 12mm. Does this seem OK. It is a mismatch of campag cranks and different shaft? old Scapin frame. I have noticed some cranks push onto about 2mm from shaft end? any thoughts, Cheers Ben
bjohn is offline  
Old 03-07-11, 09:42 PM
  #2  
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,955

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 141 Post(s)
Tagged: 1 Thread(s)
Quoted: 5910 Post(s)
Liked 2,779 Times in 1,551 Posts
Ideal engagement has the spindle ending roughly 2mm sub-flush. You have less than ideal though you didn't say whether that's after you torqued it on. 12mm engagement is reasonable though another 2-3 would be nice.

This isn't a digital pass/fail concept, more engagement is better, less is worse. Whether you have enough depends on things like what you weigh, and your riding style. For a 150# spinner, I'd say no problem. For a 200# masher, it might be dicey.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

Just because I'm tired of arguing, doesn't mean you're right.

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 03-07-11, 09:49 PM
  #3  
Senior Member
 
Join Date: Jan 2008
Posts: 295
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Sounds like you're pushing ISO cranks onto a JIS spindle.

While the engagement is fine, my crystal ball sees you sorting out loose crank arms ... over and over. Just get a ISO bb.
sideshow_bob is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
noobinsf
Bicycle Mechanics
17
11-02-15 02:45 PM
jpsawyer
Bicycle Mechanics
1
05-10-14 11:36 AM
joseph senger
BMX
0
07-03-11 04:50 PM
bigshuse
Bicycle Mechanics
8
10-16-10 01:52 PM
xenologer
Bicycle Mechanics
13
12-11-09 11:47 AM

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.