Torque, an un-assuming little beastie, it’s always there and harms no one unless you abuse it, the stripped thread/broken bolt will have you rolling about in a fit of expletives.
What the hell is it and why is it so bloody important not to piss it off
Put simply (very) it’s how tight a nut or bolt is and should be, not tight enough the bolt/nut might vibrate off or warp the thing it’s holding together, too tight and it can warp the thing it’s holding together or the bolt may snap or you’ll strip the threads in a blind hole.
Either way it’s problems which are easily avoided. There are two ways to tighten a bolt/nut, 1 .put a socket wrench on and put a six foot scaffolding pole over the wrench handle, get the bolt/nut tight then jump up in the air and put all your wieght on the pole. You’ll know when the process is complete by the bang, crash, snap noises as you fall on you’re arse and the bolt snaps or the thread gives up and goes home. 2. Use a torque wrench to achieve the correct tightness, Note : It’s not always necessary to use a torque wrench, it depends how adept you are at judging tighness by hand, when fitting cylinder heads, cam bearing bolts, crank bearing bolts and other warpable/expensive if broken bits then it’s a must.
Disc bolts, caliper bolts, wheel spindles or you’re heavy handed, it’s a good idea to use a torque wrench if you’re not sure.
First thing to do is buy a torque wrench from your local tool shop/mail order/Granny, the latter may not be much use since the torque wrenches used in knitting may not have high enough torque settings
There are many makes and size of torque wrench, often, the one’s meant for cars just don’t go low enough in the settings, i.e 10nm (newton metres, guess old Sir Isaac had problems wiv his bike), The table below show that 6nm is the minimum, so look for a torque wrench that goes from 0 to 150nm, you might not be able to get one with the whole range , I’ve got two, a wee one and a big ‘un but some clever git’s probably made one that does it all.
Here’s a table of common torque settings, These are very general, the setting will depend on the material, whether it’s a bolt, nut, tapped hole etc. If possible refer to your Haynes Manual or better still Workshop manual.
General Torque Setting (Nm)