Torque wrenches

(1/3/2014) If you are going to work on your bike, it is very important to have two torque wrenches in your toolbox, each of a different scale:

1. foot pounds
2. inch pounds

Above/right is a photo of my two wrenches, the newer one (inch pounds) is in its plastic case. I made the mistake of throwing away the case for the larger, ft.-lb. wrench, so it would fit in my toolbox. I now realize that it's very important to keep these wrenches clean and the case helps toward that end. I am going to be sure to keep this case and rearrange the contents of my toolbox to accommodate the new arrival.

These are both called "click" or "clicker" type/style torque wrenches because they make an audible clicking sound when you reach the set torque. This offers the advantage of not having to see the wrench in order to know when you've reached the correct tightness. You don't have to have much experience working on motor vehicles to appreciate this feature, as you are often inserting your tools into crevices that make reading a dial very difficult, if not impossible.

I confess that it was only recently that I purchased an inch-pound torque wrench. (I've had a foot pound wrench since 2000, the year I bought my Harley Davidson Road King Classic.) I became particularly motivated to purchase the inch-pound wrench because I want to change my oil pressure sending unit and the creator of a YouTube video I watched on the subject pointed out that getting the torque right is especially important for this component.

As you may know from reading some of my recent blog posts, I recently changed my front brake pads, and the pad pins also call for a specific torque, i.e., 180-200 inch pounds. As I did not have an inch-pound torque wrench available, I had to tighten the pad pins to what "felt" right, which is really not a good idea.

Now that I have the new wrench, I plan to go into my garage this weekend and tighten the fasteners for which the manual specs inch-pound torque values. I've included a table below with some examples of both foot-pound and inch-pound values for some of the threaded parts we more often have to deal with, such as spark plugs.

Why you need torque wrenches

There are three reasons that come to mind immediately why you need to torque fasteners to their specified tightness:

1. To avoid cracking or otherwise breaking the fastener, e.g., bolt, screw, etc.
2. To avoid having the fastener come loose during vehicle operation, and
3. When a gasket is involved, to prevent squeezing the gasket beyond its optimum pressure, possibly damaging it or leading to a leak, or both.

Read the documentation!

Be smarter than me and read the documentation carefully when you get a new torque wrench. Now that I am writing about such matters, I do read the documentation. However, it would have been a good idea for me to read it when I bought the first one. Had I done that, I would have learned to set the wrench to 20-25% of its maximum when storing it, and never reduce the tension down to zero. Because I hadn't read the manual, I violated both of these rules. The wrench seems to work fine but I realize now --having read the manual for my new inch-pound wrench--that I should take the foot-pound wrench to Sears and ask about getting it calibrated. (It's a Craftsman brand.)

We were not born with the knowledge as to how to properly use a torque wrench and most of us are guilty of passing along erroneous information from time to time, so it behooves us to take responsibility for our own skills development and read the instructions.

For example, here's something else I learned when reading the instructions: the torque wrench does not prevent you from overtightening a fastener. If you keep tigthening even after you hear the first clicks, it is possible to overtighten the fastener. Of course, this begs the question, why would anyone work harder than necessary? (If you're hearing impaired, my apologies if I've offended you, but you should have chosen a different type of torque wrench, such as one with a digital readout.)

Torque specifications for certain fasteners on my Harley:

Brake pad pins:	180-200 in. lbs.
Brake caliper mounting bolts:	28-38 ft. lbs.
Front axle nut:	50-55 ft. lbs.
Front axle holder nuts:	132-180 in. lbs.
Engine side cover:	84-108 in. lbs.
Spark plugs:	12-18 ft. lbs.
Oil pressure sending unit:	96-120 in. lbs.
Oil pan drain bolt:	14-21 ft. lbs.

Foot pounds can be converted to inch pounds by multiplying by 12, or inch pounds to foot pounds by dividing by 12. For example, 1 foot pound = 12 inch pounds.

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Please pray for a short winter (mild seems to be gone), and as always,
Keep the shiny side up!

-The Long Rider