If you don't have one, this method works identically. Just need a a little math.



PLUS



Equals torque wrench.

Remember though, if you aren't using Torque Fluid your readings will always be about 25% erroneous.

A 3/8" seems reasonable to me for cranks and BBs; a 1/4" seems reasonable for about everything else.

And, for general duty, there is nothing wrong with Harbor Freight torque wrenches, contrary to some opinion. Waiting till they are on sale will get you one for less than $15, maybe even 11 or 12. I would go for 1/4 inch, a 1/4 to 3/8 adapter, and a set of allen (hex) sockets. Inch pound scale is nice for bike work. Be brave, and buy 1/4 and 3/8 wrenches when they go on sale.

I got my torque wrench from PBK . Its adjustable from 3-15Nm , HEX 3,4,5,6 mm .

Close enough only counts in horse shoes and hand grenades.

I build engines on the side and torque specs are there for a reason. Over or under tighten a bolt can cause it to snap or come loose. On a carbon bike you can pull the embedded nut out which means the part hast to be replaced. Carbon stems are not cheap, but a whole lot cheaper than a frame. Or worse the stem can come loose when you're riding.

If you're willing to trust your bike to a $15 torque wrench, please don't ride in front of me.

BTW... i read a car magazine review of a Harbor Freight 1/2" drive that when set to 70ft-lbs, it was actually 65ft-lbs which his 7.15% off.

Sort of 70ft-lbs is not very accurate.

I just got a Ritchey torque driver. Its set at 5nm. Works for all the small stuff. Try out homedepot.com they have lots of torque wrenchs online that are way cheaper then the park tool stuff.

Yeah, I read, that my uncle's neighbor saw it happen....... A lot of fear-mongering without real proof.

I have read exactly the opposite. That HF torque wrenches perform as well as any other.

And, I'll bet you never saw or heard of a S-K, Snap On, or Craftsman tool failing, either.

With proper maintenance and storage, the HF torque wrench performs as well as any..... and accurately, too!

Wow! You are so cool! Can I hang with you IRL?

That test was the result of improper storage............ and they knew it! The original proper test showed "the original test that shows the wrench varied between 69 and 70.3 lb-ft," at 70# indicated ... i would classify that as acceptable.

Read more: https://www.hotrod.com/how-to/additio...#ixzz3lYfYSFdf

There's an adage for buying tools: Buy a good tool and cry only once when you buy it, buy a cheap tool and cry every time you use it.

That said, matching the quality and cost of a tool to the required precision and intensity of use makes sense to me. No doubt that torque wrenches by Snap-On and other high quality brands are far better and far more consistent than what you can get from HF. Of course, they cost 10x as much, so they should be better!

And the risk of getting a HF wrench that is >10% out of spec also has to be much higher. But if you have a way to calibrate it every now and again, then I suspect the HF will serve you fine -- the tolerances on most bike fittings are probably really wide relative to other applications that spec a torque.

Any reason to believe the torque specs on a bike require more than +/-10% accuracy?

Steel or alloy... maybe not. Carbon, maybe yes.

a good 1/4" torque wrench will not sit on the shelf with me, so i don't mind buying a quality tool. If you're gonna use it only a few times a year, then maybe $100 is too much to sit on a shelf.

I'm fairly certain we don't need NIST traceable torque wrenches with 1% accuracy to put together a bike. Any decent manufacturer would design in plenty of safety margin. I very much doubt that tightening a bolt spec'ed to 5nm to 5.5 or 6nm is going to cause a problem. If it did you should look for a better bike.

A CDI 5nm key and a set of hex bits will perform most all of the common tasks.

Don't use it to loosen anything. That may effect the calibration.

Get a Harbor freight 1/4" and 3/8" for everything else and get religion about only storing them with the setting at minimum.

It's a bicycle, not a rocket ship. the tolerances aren't that tight.

The bike is a Trek Emonda SLR, so getting a "better" bike is not really an option.

1%, no... 10% no also.

You/I really have no idea. +50% may be perfectly acceptable. Your bike is not as delicate as you might think. Pretty sure the average bike mechanic or owner is not sending their torque wrenches in for annual calibration.

Had one of the bottle cage bolts snap. it took some time to remove the remaining piece in the down tube bung. It was torqued to spec, but the bolt was alloy and the spec was for a steel bolt. I remove the other bolt and could see that it was stretched. After contacting the manufacturer I found they recommend a much lower torque spec, unfortunately they didn't specify it anywhere on the packaging of the cage. The cage was Bontrager... aka Trek.

Just glad the bung was not damaged. I've seen a seatpost bung that was cracked from over torque. Not a cheap fix.

Agree that bolts shouldn't be overtightened but the actual force that's applied to stretching a bolt is highly variable even if you are applying torque within 1%. How much lubrication is on the bolt threads and any mating surfaces of the bolt affect how much of the torque you apply is translated to stretching the bolt vs overcoming friction.

I guess my long winded point is that the Harbour freight torque wrenches are fine and won't wreck your bike.

Dude... you torqued your water bottle cages to spec? Your. Water. Bottle. Cages.

And you expect to people to take you seriously?

The spec is way less than you'd do by hand.

They list a spec for a reason. If I did it without a torque wrench I would of snapped them immediately.

Dude.

Then you are 100% ham-fisted.

And you expect people to take you seriously?

Sorry but my hands are calibrated for 14ft-lbs and not 4.5nm.

My two fingers and thumb are calibrated to 4.5 N-m, not my hand.

I bought one of these for the more frequent little stuff, seat post, handle bars, cages, etc. Anything bigger, I'll borrow one from work.

Really convenient too. No need to search for the right size. Just grab and use.