Proper use of a torque wrench

When using a torque wrench, remember to measure twice and torque once. I was installing my cranks, and looked up the proper value. Put the crank on, attached the bit to the wrench, and started cranking away.

"hmmm, this is starting to get real difficult, and I'm just over half of the target value" I thought to myself.

But I had a torque wrench, so I could do no wrong. It wasn't until I got to the point that I was about 20 ft/lbs shy and I could barely budge the wrench that I decided to take a break and see if I could figure out what was going on.

It turns out that when I looked up the information in my Park Bike Repair book, as I went from the left side of the page to the right, I somehow wound up on a different row. The actual necessary torque value was something like 20% of what I was incorrectly trying for. The crank was squished on so tight that the FD was rubbing on the chain.

I quickly removed the crank and put it back on using the proper torque value and counted myself lucky that I didn't split the end of the crank open.


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