Saturday, October 11, 2008

Seven or 666?

Still working on the $12,000 beater bike, I finally achieved smooth front shifting after four derailleurs and four bottom bracket configurations on top of the new chain rings and several shift cables. I started to think the bike was possessed.

The funniest part is the derailleur. What works? Not the modernest marvel I could order. No, what shifts cleanly is a Deore from about 1991. It matches up with that misapplied Ultegra brifter like it was born to do it. But is it worthy of a $12,000 bike? I put the question to the owner. He says he'll try it.

The new XT derailleur I was trying to install to replace the worn-out XTR would fray the shift cable every time I tightened the anchor bolt. I burned through five or six cables while trying different configurations. Remember, kids: bad design is not a manufacturing defect! No warranty for you!

Our parts bin now has an XT front derailleur and an XTR Octalink V1 bottom bracket (116.5) that we may never use. We'll probably place the derailleur, but who is going to need that BB?

I ordered the wide BB after I couldn't get the chain to drop to the granny with the old one, because the front derailleur was already folded up as tightly as it would go. Only moving the chain rings outward would put them under the dreailleur in that position. Since it's hard to find detailed dimensions on current componentry, let alone obsolete stuff, I didn't find out until the new BB arived that the axle only sticks beyond the end of the bearing cartridge as far as it does on the 109.5 mm Ultegra BB that was already in the bike.

The XTR unit came with spacers for different chain lines. Interestingly, neither chain line listed in the spec sheet that came with the BB matched what I measured on this bike, so I was on my own. The BB that finally worked was the original one with 1.5 or 2 mm of spacers behind the flange of the drive side of the bearing cartridge. The new one would have worked as well that way, but his left crank arm would have been dangling way off the left side, making the tread measurement of his bike much wider than before. Since Seven supposedly chooses every dimension of their bikes to match customer specifications, I didn't want to widen the stance of the pedals when it was supposedly carefully calculated. So we ate the new bottom bracket.

The bike has been picked up by the owner's staff, to await its rider's return in the spring. He's off to wherever he winters, whether that's the mercantile centers of Megalopolis or Utah ski country.

No comments: