Wednesday, July 13, 2016

Tooth Removal

When I first built my Canfield a couple years ago, I went with a Shimano Zee crank and a 32-tooth Race Face chainring. I had to use an extra spacer on the right side of the bottom bracket so the chainring would clear the chainstay. Consequently, the left crank arm wasn't on the spindle all the way, and the chainline was less than optimal. However, what bugged me the most was the fact that one crank arm was closer to the frame than the other. Asymmetry completely freaks me out! I figured it was only a matter of time before that 2.5 mm of offset caused my hip to explode.

In a completely unrelated move, I bought this M782 crankset about 18 months ago for $99. It features yet another bolt circle standard (96 BCD) introduced by Shimano which allows for a 30-tooth middle chainring. I didn't really have a burning need for it, but the price was right. What could I do? Not buy it?

I figured eventually aftermarket chainrings might be available. The cranks were filed away in the archives and forgotten.

Fast forward to now, and there are a few companies making narrow-wide chainrings in 96 BCD. I chose the Wolf Tooth 30-tooth because it has integrated threads. Unfortunately, it also has integrated spacers that positioned the chainring too far inward. It hit my chainstay.

To the Internet!

I then bought a Blackspire 30-tooth, which fit perfectly.

Now I have a little bit lower gearing, a better chainline, and my hip is no longer in danger of exploding. I can sleep comfortably knowing the Universe is back on its axis; my cranks are now symmetrical.


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