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

Crank torqueing advice please

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.

Crank torqueing advice please

Old 05-01-08, 05:42 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Dec 2005
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Crank torqueing advice please

Hi all. I’ve been trying to do more and more in the way of basic bike maintenance over the last year. I feel comfortable with adjusting the derailleurs, brakes and replacing tubes…all essential do-it-yourself jobs. I recently bought a fairly expensive folding bike (Bike Friday New World Tourist) and did some more reading about the things one should do after riding a new bike for a couple of months. Of course I already had the derailleur adjustments down (which go out of adjustment a lot when the bike is new).

I decided to buy a Park beam torque wrench to torque the cranks, as this seems to be on the list of things to do early on (and I thought – how hard can this be?). I practiced a few times on an older less expensive mountain bike. First I undid the bolt, greased it, and then tried to torque it to specs (40nm). I found it quite difficult to read the gauge, pull on the wrench, hold the crank in place, and keep the bolt moving until the torque was reached. After going through this procedure a few times, I came to the conclusion that I really did not feel all that comfortable tackling the expensive new bike.

So here are my questions:

Is it really that important to go through this crank torqueing routine (they don’t feel loose at all)?

Should I buy a click-type torque wrench and will this make the process easier for a klutz like me? And if so, which one is recommended?

And, on another note, should I tackle the adjustment of my Chris King headset? I read a bit about this, and it does not look easy!

Anyway, any advice on the above would be most appreciated. Rich
rwgreenberg is offline  
Old 05-01-08, 05:54 PM
  #2  
Senior Member
 
Join Date: Mar 2007
Location: Louisville, KY
Posts: 469

Bikes: Trek Madone 5.5, Klein Q Pro Elite, Surley LHT

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I also, have a NWT. As for the proper torque, all bolts and nuts have a specified torque. That does not mean tight and a half turn more. After you have done some bolt tightening to the proper torque you will know when you have it within the specs. As for a click type torque wrench, A lot easier to use as all you do is set the torque desired on the wrench and tighten until the wrench clicks. Is it worth the expense? That is your call. As a retire aircraft mechanic I prefer the click type. That comes form years of using one.

The head set adjustment is rather a simple process. Try doing the procedure in Park Tools web site.
kycycler is offline  
Old 05-01-08, 08:27 PM
  #3  
Healthy and active
 
twobikes's Avatar
 
Join Date: Mar 2007
Location: Caldwell, Idaho USA
Posts: 887

Bikes: mid-60's Dunelt 10-speed, Specialized Allez Sport Tripple, Trek 7.2 FX

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I made my own torque wrench using a steel bar and a dial type fisherman's scale that reads 0 to 50 pounds. The nominal distance between the scale and the tool is ten inches. The dial is easy to read. 35 pounds is 350 inch pounds, which is about what my bikes requires for the bolts that hold the cranks on the bottom bracket shaft. I mentioned the nominal length of the steel bar because I weighed something of a known value and found the scale read six percent light. I shortened the distance by six percent to compensate. The cost of my wrench was about $5. Park Tool's web site has a conversion table for Newton meters to inch pounds, etc.

On adjusting your headset, I assume you are talking about putting some tension on the screw in the stearer cap before tightening the stem bolts. It is really pretty simple. Perhaps I do not understand your question.

I do like to torque to specs wherever specs are given. There have been a number of threads on this during the last year. Some use a torque wrench. Some insist they can do it by feel after gaining some experience.
twobikes is offline  
Old 05-01-08, 09:40 PM
  #4  
Senior Member
 
Old Hammer Boy's Avatar
 
Join Date: Aug 2005
Location: Utah
Posts: 1,082

Bikes: Trek, Cannondale Tandem, Surly LHT

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It's important to keep your crank arms tight and properly torqued. If they aren't tight enough, you can fairly easily damage them. Because they are aluminum, the spindle of your BB can "eat" into them from the hammering resulting from a loose crank arm.

Whether you use a beam type or clicker wrench, it really shouldn't be that hard. As both wheels are on the ground, I just grab onto a pedal and tighten 'er up, working 180 degrees against myself, until she meets spec. Perhaps you could have a friend help hold the crank arm as you tighten. At any rate, don't neglect this chore, you could ruin your crank assembly.
Old Hammer Boy is offline  
Old 05-02-08, 10:35 AM
  #5  
Member
 
Join Date: Dec 2007
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
speaking of torque. this thread got me looking for a torquing guide which i found on the park site:

https://www.parktool.com/repair/readhowto.asp?id=88
bifo is offline  
Old 05-02-08, 02:07 PM
  #6  
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Posts: 6,925

Bikes: 03 Raleigh Professional (steel)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I am totally confused.

Why would you go to expense of buying a torque wrench and then try to rationalize not using it?
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline  
Old 05-02-08, 05:47 PM
  #7  
Junior Member
Thread Starter
 
Join Date: Dec 2005
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by DMF
I am totally confused.

Why would you go to expense of buying a torque wrench and then try to rationalize not using it?
I think the expression is, "I'm chickening out."
rwgreenberg is offline  

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.