19 January 2017

Thank you for your service, Yamabushi

Yamabushi under construction
Photo after paint job
Closer to what it actually looks like these days ... a working bike, not a show one!
It is five years ago next month that I built a frame at UBI (bikeschool.com) in Portland, which once built up and back in Japan was christened the "Yamabushi". It was designed for cyclocross, which I have never really taken up. So instead carried me on the 1300 kms in Tohoku that I rode that Golden Week, many other trips on forest roads, gravel and smooth pathways. By late in 2012, it had become my commuter bike -- with fenders for keeping my legs and ass dry in the rain, dynamo lighting front and, eventually, rear, and a different fork with disk brake added to the front, for better (and more nuanced) stopping power in the city than the original canti brakes.

Then another 4 1/2 years of commuting use, over 100 kms almost every week, sometimes closer to 200, within the city. It has my name painted on the top tube (though wearing thin now), was very large for Japan, and looked just odd enough so I never worried about it being stolen (and it never was).

The latest overhaul was a few months ago -- new shifter cables, new chainrings on the crankset, new chain, and FD and RD adjustments.

So it was a disappointment when, on my commute home yesterday, the front derailleur cable broke, down near the derailleur itself.  I wrapped the loose cable around the top tube and rode on.  But something was wrong.  There was an odd motion and noises, as if the seat were not secured onto the post.

I dismounted and checked for broken spokes, loose seat, etc.  Nothing.  I rode further. The bike seemed normal when I did not apply my weight to the saddle and seat tube, but abnormal when I would sit.

I checked again and noticed a gaping crack around the seat tube at the BB joint.  Here:

When we built these at UBI, the final welding test before students were allowed to start work on their frames involved welding a tube to a BB shell. A large diameter metal rod was inserted into the tube, and the student applied all his or her weight to the metal rod, until it broke.  If the break was somewhere in the tube, the weld had "held" and you could start your frame.  If the break was at the joint with the BB shell, your weld had "failed" and it was back to the practice table.

Unlike most of the class, I did not pass the first time.  And looking at the crack on the Yamabushi frame, it reminds me of the broken tube after that first test.  A failed weld.

But at least it made it 5 years and tens of thousands of total kilometers, with a heavy rider, in urban stop/start conditions frequently with a heavy pack on my back full of books, computer, etc.

What bike will I commute on now?  Mmmm.  I picked up a couple bike registration stickers at the university so I can take my time in figuring out which will be my primary ... but unfortunately these stickers are pretty much permanent, or will ruin a paint job!
UPDATE: I may have been a little tough on myself and my weld in the above post. Hiroshi at C Speed showed me a Nagasawa frame that is broken in the same place after many years of service. "Metal fatigue", plain and simple. And, thinking back, I realize that I did go "off the bike" once in late December, when a delivery motorbike (trike?) made an illegal left turn -- cut through a line of standing cars on Komazawa Dori and pulled in front of me with me going at a normal speed (25kph?) and only a few meters to stop.  I was not injured nor did I see any damage to the bike, so accepted the shop owner's apology and went on my way. ... but a month later, I fear that maybe this started a crack in the frame. ...

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