Rules of thumb for estimating ft/lbs of force?

[Grey Thumper]

I'm planning to change fluids for the tranny and final drive. 22ft/lbs are recommended for the tranny plugs, 17 ft/lbs for the final drive fill plug (about 30 Nm and 23 Nm respectively).

I've got the right socket (19mm) for the FD drain plug that fits my torque wrench, so no prob there, but don't have hex sockets that fit, just hex wrenches.

Should I be anal about the torque setting? Is there a rough estimate for 22 and 17 ft lbs (hand tight + 1/4 turn, or something like that)?




Edit: added metric values.

[macx]

That depends on a lot of variables - including what everyone's definition of hand tight
and snug tight etc etc etc are.

But I'll take a stab at it, after years of spinning torque wrenches assembling all kinds
of things.

Assuming you are a normal male with average strength in the hands, I'd say this -
With a standard length allen wrench and using 1 hand, tighten it until you start to
feel significant resistance. (another term for interpretation) Don't use most of your
hand strength but snug it up pretty good. If you change oil in your car, and haven't had
any problems with stripping the oil pan plug, kind of go by that. Or if you change spark plugs
esp in an aluminum cylinder head. Good and snug but not seriously tight. As the crush
washer starts to crush, you'll feel increased resistance. When it gets close to fully crushed,
that resistance will increase significantly in a very small amount of turn. Then it's definitely
time to stop.

Probly better a little on the loose side rather than giving it that "last little tug" that so often
results in stripped threads. If it leaks, you can always snug it up a little dab more. If you
strip it to start with, you've got more problems than a small leak. Err on the side of caution.
Your crush washer will help seal the plug and will be effective over a relatively wide range of
torque.

Boy, wasn't THAT specific? :-/

OR, you can get allen head sockets that'll fit your torque wrench at a reasonable price.
You don't need the high $ ultimate quality sockets for that, you can do just fine with
cheap ones for that.

Undoubtedly the safest idea overall. Good luck.

[MIXR]

A 'rough estimate' of torque value on my front axle bolt by my service guys is what screwed up my brakes! Big time problems. The thread about it is here somewhere.

Torque values are there for a reason. There are some parts that you can get away with 'guessing'. There are some you can't. I know some guys (in my Air Force days) who could be pretty consistent in 'guessing' torque values. Do you want them to get it right 9 out of 10 times on something critical on your bike, when you are number 10? Don't think so.

Get the right bits from a cheapo tool shop. If the torque wrench is ok, the other parts (adapters, sockets etc) will probably work ok if used carefully. An overtorqued part like a plug won't be problem until you go to undo it next time. That's if it doesn't fall out first because it was too loose. If it was too tight, it may just break something instead of cracking loose. That's the risk.

There are lots of things I don't torque. There are some I do. You have to make up your own mind what's important.

[Xdot]

Get a torque wrench. It matters, and they're not that expensive.

[boxermania]

Like everything else, practice makes perfect. I can use my impact wrench to tighten wheel lugs and be within 4 to 5 ft-lbs from the torque wrench value, but I have done that a zillion times during my life.

Personally, I have a problem using a torque wrench on soft materials and low torque values as it is easy to make a mistake and damage something.......I do use a torque wrench but for specific tasks only.

[EH2Zee]

Get a torque wrench. It matters, and they're not that expensive.

Do you folks typically recemmend to have two torque wrenches - one for the little stuff and one for the big stuff? I have a hard time believeing that my (admittedly cheap) torque wrench is even close to accurate in the lowest ranges...

[iowabeakster]

Yeah, your wrench is probably inaccurate in the lowest part of it's range.

Two wrenches is a good idea.

[Keppelj]

Well, and then there's the choice between bar and "click" type wrenches. Bar type is fine until you get out of position and can't read the scale like with the oil sump drain plug. Pricey, but I'd like "click" types for both low and high torque settings.

[MIXR]

Two types of click - One with a moveable head, and one with a release pin. In order of quality, I'd go the pin type, then click head, then bar. The bar ones are rubbish and difficult to maintain in calibration. The other end (pin type) is damned expensive. Depends on how much work you are planning. You need a foot-pound one for big stuff, and an overlapping inch-pound one for the small stuff. Look for 'sets' of two wrenches from some makers and save even more money, and get a nice plastic protective box as well. And ALWAYS release the tension setting when finished, even for lunch breaks! And put the wrench back in its box as soon as you are done. Some bigger tool stores may offer a relatively inexpensive calibration service. Shop around for that.

[ccameron]

I bought the click type torque wrench at Lowes----Kobalt. After reading many torque wrench comments I was concerned with accuracy. My brother is an aircraft mechanic at FedEx and he took my wrench in immediately after I purchased it to have it certified. It was dead accurate on all tests they performed! Many of the other mechanics were amazed as the spent 3 to 4 times as much for superior wrenches (snap-on, etc.) Good value ($90), lifetime warranty and accurate! I would suggest you get any new ones tested to ensure accuracy after some of the horror stories people have written on this forum. Hope this helps!

[jcridge]

Drain plugs can be torqued, just not over torqued or left loose. Torque is better, but the industry on a whole uses the hand tightening method.

If you feel an extra measure is needed, we used to drill and wire plugs and bolt heads, and use lock-tite for those critical fastners.

Just remember when you use a torque wrench, to find out if the manufacture requires dry or wet threads,and if using a click type, pull using a flat palm up grip and complete the final torque in the middle of your motion. You just don't want to be 90% there and have to stop and start again.

John

[R1150Rclean]

I got a CDI 602NMRMHSS 10-60 nm torque wrench (a Snap-on company) for $140 including shipping. It is a work of art from a tool perspective and covers all the regular torques you need for the bike. Comes with a calibration certificate.