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

40 Nm without a torque wrench

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.

40 Nm without a torque wrench

Old 04-28-18, 01:51 PM
  #1  
Semipedersen
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 126
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
40 Nm without a torque wrench

Hi, another beginner question. I bought the Abus Nutfix wheel locking system today. It says in the instructions that I should tighten it with 40 Nm. I cannot use my torque wrench because of the design of the Abus Nutfix. Is there an easy way to tighten something to 40 Nm with an open—end wrench?
Semipedersen is offline  
Old 04-28-18, 02:36 PM
  #2  
kyumin2lee
Junior Member
 
Join Date: Apr 2018
Posts: 11
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
40Nm means a moment of 40N - equal to around 4kg, at a distance 1 meter from the pivot. You could get place a 4kg weight on a 1m bar. You can scale it down - so 8kg on a 50cm spanner, 16kg on a 25cm spanner, 32 kg on a 12.5cm spanner and so on.

But realistically, 40Nm to me is 'pretty damn hard'. I'm sure the locking mechanism or the axle isn't particularly sensitive to the proper torque, you just don't want your wheels falling out of the dropouts mid ride.
kyumin2lee is offline  
Old 04-28-18, 02:52 PM
  #3  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,322 Times in 832 Posts
A having a torque wrench a couple uses can give you a feel for what that is like, then thereafter, you may not need it as much.

have something else you can use a torque wrench on, to rehearse the feel of how tight that is?

https://www.abus.com/eng/Mobile-Secu.../NutFix/NutFix

there are 'Crows foot' bits to use on a torque wrench that are open end , with a square socket bit hole


Last edited by fietsbob; 04-28-18 at 02:57 PM.
fietsbob is offline  
Old 04-28-18, 02:52 PM
  #4  
RGMN
Senior Member
 
Join Date: Feb 2018
Location: Twin Cities,MN
Posts: 466
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 210 Post(s)
Liked 166 Times in 114 Posts
Originally Posted by kyumin2lee View Post
But realistically, 40Nm to me is 'pretty damn hard'. I'm sure the locking mechanism or the axle isn't particularly sensitive to the proper torque, you just don't want your wheels falling out of the dropouts mid ride.
That's barely 30 lb.ft, not even close to pretty damn hard. More like almost moderately tight.

To the OP, take a nut & bolt that use the same size wrench as the Abus Nutfix, torque it with the torque wrench to 40 Nm, and then take the wrench and see how tight it feels. Then try tightening the nut & bolt with the wrench and check if you hit 40 Nm. It will take a few tries but you should be able to get fairly close after you "calibrate" your arm. Then tighten the Abus Nutfix.

Alternately, you could get an appropriately sized crows foot and torque it with that.
RGMN is offline  
Old 04-28-18, 03:09 PM
  #5  
Semipedersen
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 126
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Crows foot you guys are great! I will get one next week. Never knew that something like that exists. Thanks for the help. I need more tools.
Semipedersen is offline  
Old 04-28-18, 03:23 PM
  #6  
Ol Danl
Senior Member
 
Join Date: Dec 2004
Location: Chattanooga, Tn
Posts: 276

Bikes: 1977 Raleigh Record, 1987 Schwinn Prelude, 1971 Raleigh Record, 1988 Schwinn Traveler, 1967 (?) Carlton Super Course, 1959 Huffy Sportsman 3 speed, 1972 Raleigh Super Course, yet another 70-something Raleigh Record

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Liked 2 Times in 2 Posts
We use torque wrenches at times in my craft, and our training has us make sure a crow's foot is at 90 degrees to the handle to get the torque value right.
Ol Danl is offline  
Old 04-29-18, 04:01 PM
  #7  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 2,847

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1062 Post(s)
Liked 259 Times in 195 Posts
Ol Danl is right: use the crow's foot at 90 (see drawing). If you must used the crow's foot at 0, you can do it, but lower the click-setting torque you set on the wrench by a factor of L/(E+L).

WizardOfBoz is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
WGB
Bicycle Mechanics
19
09-25-19 03:05 PM
maartendc
Bicycle Mechanics
15
02-09-18 08:38 AM
skids929
General Cycling Discussion
22
04-26-17 01:30 PM
soom
Bicycle Mechanics
15
03-15-16 09:25 AM
Foilnz
Bicycle Mechanics
9
11-18-14 01:52 PM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.