Installing the new FSA GRADIENT CRANKSET and the weird threaded bottom bracket

The stock cranks on my new Karate Monkey suck.

But it's hard to find a good crankset that works with a normal 73mm MTB bottom bracket.

Luckily FSA decided to do something smart: make a freaky BB392 crankset AND make a threaded bottom bracket so that you can instal it in a normal bike.

I Give You the Gradient: 

 The Gradient works with either a single or double chainring, and comes in 170mm and 175mm lengths. It's pretty light and the 30mm wide spindle should be pretty stiff. Most importantly: it looks cool. Like the kind of crankset you might see Darth Vader using to club down some rebel scum.

Now the part where I tell you how to install it:

1. Check out the tools.

Here we have a big socket driver, crank puller, torque wrench in newton meters, 8mm allen, overpriced FSA BB tool, and a regular BB tool. Not pictured is a 10mm allen that I forgot about and probably some other stuff. 

2. Take off the old Bottom Bracket and cranks. 

The securing bolts come off with a 8mm allen. Lefty loosey on both sides. I usually take the pedals off first because it's easier to get leverage when the cranks are still attached to the bike, but there's no rule.

Make sure to take the chain off:

And use the crank puller to yank the arms off the spindle

 Now here's the tricky part: the drive side (right side) of the bottom bracket is reverse-threaded. That means righty loosey, lefty tighty.

 The non-drive side is normal though.

3. Screw in the new FSA BB392 to BSA Frame Bottom Bracket.

This part is pretty annoying because you need a special tool, which you can only get through FSA for $60. As of this post, there isn't even a spot on the regular FSA site to buy the tool (I would have linked it if there were) so you have to get it from a dealer. Ugh. Good news is that it uses a 1/4" in driver, just like my torque wrench, so putting it to the recommended 50nm was simple.

Anyway, it was easy to screw in, but the other annoying thing is that the crank spindle is just a smidge too big for the bottom bracket's inner diameter, so I had to smack it with a hammer to get it all the way in.

I actually used a rubber mallet, but I forgot to take a shot before I put it away. 

4. Last thing you want to do is torque it down. 

Officially you'll want to use a real torque wrench with a 10mm allen bit. But I lost my 10mm bit, so I just did it by feel. I checked my work a few days later at the bike show with their torque wrench and I was pretty close to the recommended 40nm.

5. OK the real last thing to do is screw the pedals back on and take it for a test ride off some jumps!

And hey, if you like this post, check out the one about the Surly Karate Monkey from the photos.