Park Tools Torque Wrench
 

I bought the Park Tools torque wrench (the larger one) as part of my winter project of replacing the groupset on my Giant OCR-1 with the Ultegra group. I'm wondering why the wrench handle ratchets back and forth. It's obviously designed to do that (there's one pin that holds the handle to the main shaft of the wrench), but I can't figure out why.

I should add that I've never owned a torque wrench before.

I know some people never use torque wrenches and I respect that, but I figured if I'm going to do this, I ought to at least attempt to do it right. As such, I'll probably now try to torque down everything in sight. What would be the most critical parts to torque down on a project like this? Is it a good idea to do the pedals, for example?

A torque wrench is designed to measure foot pounds. That's literally 1 pound of force applied 1 foot from the axis.

If the handle didn't pivot on a pin, the force that you apply would be spread over a range of about 4 or 5 inches. The handle pivot concentrates all of your effort at one measured point. Incidentally, when you use it, you should take care that the handle stays free floating.

Absolutely correct! The pivoting handle shouldn't contact the the wrench arm when applying force or you will get an incorrect torque value reading.

Thanks.

Any suggestions on what to torque?

The big one for bicycle use is pretty much limited to bottom brackets and crank arm bolts. 30 lb/ft is a typical spec for those. If left to the SWAG system I suspect that I'd generally under torque those.

To me, one of the main values of owning a torque wrench comes from "calibrating" the user. You will learn what 25 inch-pounds or even 60 in-lb usaed on a small fastener feels like. You will learn what 100 ft-lb (for a monster bolt) feels like. Basically, you will learn how hard to tighten certain types and sizes of fasteners. Then, even in the abscence of a torque wrench, you will be using the correct torque value (or at least closer than without the understanding you will soon learn).

There are very few critically torqued fasteners on a bicycle. I alwys worry about over/under torquing the quick release levers on my axles and causing excessive preload on the bearings when the axle compresses. I've had (in the distant past) troubles with crank bolts coming looses far from home with no special socket wrench to tighten them.

BB cups for sure, then cassette lockrings. Most people would apply too little torque to lockrings. The new Campy UT crank spindle fixing bolt, joining the two halves of the spindle should be torqued to spec. I never torqued a crankarm bolt in 25 years of wrenching.

Torque wrench tip: when done with it, reset it all the way back down to zero before putting the wrench away.

The Park wrenches are beam-type. They always go back to zero on their own unless you bend something. :)

To the OP: here is Park's web page about torque wrench use and a table of recommended torque values for various bicycle components.

No link, but thanks for the suggestion. I'll go there and check it out.

+1 on calibrating the user.

the newer ones are. they use to offer the TW-4 torque wrench

OP- use a 1/4" drive wrench on smaller bolts and carbon parts.
I prefer a torque screwdriver for these.$$$

So how many hosed out left crankarms have you encountered in 25 years of wrenching?

Any thoughts on the best make of torque wrench with a reversible ratchet head? It seems that one having this facility would be needed for BB cups.

You are supposed to measure dynamic torque and not static. That is, the nut/bolt has to be moving to use a torque wrench properly. Also, the threads are supposed to be greased unless locktite is called for.

I use the same wrench. It's identical except for the metric scale to an old Sears wrench I used to have.

Al

Whoops, forgot to click "paste" to post the link.

Any beam-type wrench is reversible. Many clickers are too.

"The best" torque wrenches cost thousands of $$ (or ££). You might want to refine your question a bit. :p

Allrighty..... what ratchet torque wrench (I assume reversible) offers the best value?

I ask as I've tried three different ratchet ones in my workshop, and with the advent of outboard hubs it looks like I'm going to have to invest in few.

I have seen ratchet/click type torque wrenches go out of calibration. When I was working in manufacturing these, and torque screwdrivers, were required to be checked for calibration regularly. Torque wrenches, micrometers, calipers etc all had calibration stickers and were forbidden to be used if not within calibration date, or if they were dropped or subjected to other abuse, until the calibration was rechecked.

The beam type of torque wrench is more foolproof and rugged IMO. As long as the pointer returns to zero without a load applied then the torque wrench should be accurate.

Craftsman. I have an in/lb and a ft/lb

-R

Many thanks.