was working with the torque wrench today on some very delicate roadie parts.

I remember touching on a subject at uni for maybe half a lecture about the importance of torque settings and how you get dry and lubed torque settings.

i remember there was an equation relating to coefficient of friction of the lubricant and the dry torque value given.

Looking at the torque sheets i was working off it just specified torque , neither dry nor lubed jst specified torque to be 40-50 Nm for one and 8Nm for another and 4 Nm for another

Are manufacturers torque values for dry assembly or lubed assembly(and if so is there a generic lube that its specified with ? )

or do they just not bother with this faff and just specify any old torque they see fit (as most of the bike trade doesnt seem to fall into any of the engineering stuff i learned at uni)

Surely the lube has a very small affect (<5%) at the business end of things (fnarr fnarr).
But seriously, it’s probably less important than how calibrated your wrench is?
Perhaps?

Unless otherwise stated, always assume dry. This is how the aviation (And I believe motor manufacturing) industry works. IT assumes CLEAN dry threads, unless the part is designed to be inserted lubed (and it says so in the manual/fitting guide) in which case any specs from that are obviously “wet”. Ultimately very few things on a bike are overly torque-critical (i.e. most things dont rely on pinch bolts that must be bang-on or perfectly adjusted cone bearings etc) and it’s better to err on the side of caution and go dry anyway as most components are designed of light alloys that strip very easily.

Most items on a bike that are designed to be assembled with loctite use the dried form of loctite, so avoiding the problem of that lubing the threads particularly.

In general wet torque is about 25% less than dry, give or take.

I’d have thought 99% of torque ratings on any consumer level bike only exists to stop idiots getting away with using a monkey wrench, backing it off a turn once it’s stripped. If you are using a moderately ‘accurate’ torque wrench and ignore any lube issues, you will be assembling a bike far better than most. At the end of a day it’s a push bike, not a plane.

a assumed dry when working today since as CK puts it there was dry loctite on and i did not require new liquid loctite

but as i remember there are **** loads of charts refering to this

http://www.portlandbolt.com/technicalinformation/bolt-torque-chart.html

also explains the equations i was talking about for working out wet torque from dry