Road Bike, Cycling Forums banner
1 - 4 of 4 Posts

·
Goodbye, Pork Pie Hat
Joined
·
4,622 Posts
Discussion Starter · #1 ·
...the Thief, His Wife & Her Lover :eek:

I've got a question about torque and it's application in component assembly.

I just recently purchased a build kit to slap on my newly-acquired Fondriest frame. While Zinn, Sheldon Brown and any number of wrenching gurus on this site say that proper bolt torque is essential for:

1) Preventing component failure while riding

and

2) Maintaing manufacturer's warranties on expensive (and shiny) parts.

I've found a reasonably priced torque-wrench (with a 3/8" drive) with which to assemble my new toy. My question is, if I put a 3/8" to 1/4" adapter on (to facilitate the smaller hex sockets I need to tighten various bolts) and thereby, change the effective distance between the point of contact and point of force (the moment arm in physics-speak), will this adversely effect the amount of torque I apply to the bolts?

Apologies if I'm not elucidating my question or even if this is essentially a non-issue, but before I start cranking on this stuff, I'd feel better knowing that I'm within the proper range.

With that said, many of the technical manuals that came with the build kit components offer an acceptable range in which to work, thus, my gut feeling is that with an incremental change in distance that an adapter represents would not effect the torque as to shift it out of that range.

Any thoughts?

Thanks in advance for your help.
 

·
Goodbye, Pork Pie Hat
Joined
·
4,622 Posts
Discussion Starter · #3 ·
Excellent. Thanks, TM. I wasn't sure if the extra distance between the bolt and the ratchet (ignoring the moment arm) would have made any difference in the amount of torque applied.

Again, you confirmed my gut instinct, but damned if I was going to take the chance on screwing something up on my first attempt at building up a bike.

Cheers,
A_B
 

·
Registered
Joined
·
1,860 Posts
Except for crow's foot sockets

TrailMix said:
You haven't changed the moment arm, as long as you're swinging the wrench around the bolt's axis (the normal usage).
The only exception is if crow's foot sockets are used (which are open end wrenches with square drive sockets). For these, you simply have to mount the crow's foot perpendicular to the wrench arm to keep the moment length the same (which will keep the torque measurements the same).
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top