The Crankset Part 1

Getting the Right Tools For the Crankset

Ok, I am going to be a little technical with the parts number, so please forgive me if unintentionally scared you away.  So, I spent sometime last weekend installing the Alfine crankset along with the Hollowtech-2 bottom bracket, chains, pedals, and hooking up the shifter cable.  Speaking of the HT-2 crankset/bb, the most economical way to install is to purchase the Parktool BBT-9.  At first, I got the BBT-19, which is essentially the same as BBT-9 except that you can snap the 19 onto the torque wrench, so installation can be done in a more professional way.  But, BBT-19 by itself is not enough.  On the other end of the BBT-9 is a cap tool, which is not found in BBT-19 and is required to secure the cap on the non-drive side.  So, in addition to the BBT-19, I need to buy either a Shimano TL-FC16 (~$3.50 + $5 shipping) or Parktool BBT-9 which I got it for $11 from Amazon.  Those tools are beginning  to cost me my left and right kidneys.

BBT-9

BBT-9 (Cap Tool)

BBT-19

Shimano TL-FC16

Observations

One thing I noticed is the 45t chainring is literally less than 1 mm away from the chainstay, on my SOMA Juice.  Well not quite, but less than 1mm of clearance.  The chainline of 42.7mm (see techdocs above) is really getting close to sawing the chainstay on the frame.  So I suggested probably 39t version of the Alfine would probably be a more appropriate choice for the Juice or similar 29er frame.

Installation

Installation is be straight forward, screw the BB cups in, insert by tapping the crank axle from the drive-side through the BB, screw the cap in the left arm, insert the plate-pin, and tighten the hex-bolts in the arm, (for more detailed instructions, refer to Shimano's techdocs here) BUT, I have a confession to make.  First time I thought I put everything together, decided to go for a ride, the left arm fell off.  What have I done incorrectly this time?

It turns out that it has nothing to do with my newb mechanical knowledge but rather my lack of attention to the spec of the frame.  Soma Juice 29er has a BB shell width of 73mm, a very common shell width for mountain bikes, and the Alfine crankset is designed for 68mm BB shell.  This is a costly mistake especially with the new HT-2 design, which the axle is welded onto the arm of the drive-side.  So you can't just replace the bottom bracket like how you can do it for square-taper, octalink, splined, or other 3-pieces crankset designs.  I love the style of the Afline crankset so much that I decided to ask people from bikeforum.net if there's any work-around to the length of the axle, and the post can be found here.  Unfortunately, it turns out there's no adapter or some extender that could solve my problem other than either milling the shell on the non-drive side, (so that the axle would stick out a little further), or replacing the whole crankset.  In addition to that, I found out there's a double chain guards version of Alfine crankset that has a longer axle, but I have no clue where to get one.

So I decided to not spend too much time on the crank itself and went with another less costly alternative.  I decided to get a Truvative triple, and hopefully, I can convert it to a single chainring with the correct chainline.  More about this in another post.