Saturday, July 2, 2011

Disposable Drivetrains

This past week I had to replace the entire drivetrain on the Scale. I was a little pissed. I had been using the same 991 cross step chain for almost a year, and when I checked the wear with a chain checker it came up as being worn, not terribly worn, but due for replacement.
I had also had the bike torn down to isolate a squeak/creak that was related to the interface of my e-type front der. needing a little grease. While I had the cranks off I also took the time to repack the bearings if my Hive Bottom Bracket.
I started doing this after this past winter I was getting a knocking sound out of the drive side of my CX bike at jingle cross. When I got it home and took it apart I found that the bearings were dry. I learned a few things (I may dedicate a post to repacking the grease in external bearing bottom brackets), but a 1000 miles later the bb is still going strong.
Anyway, while I had everything apart I took the time to grease the heads of the chainring bolts, inspect the rings etc. Get it all put back together, new chain on, and take it on a pavement ride (in the big ring). squeak is gone, but the chain wants to skip between the 21 and 24 tooth cogs on the cassette when I am in the big ring, so I shift down to the middle and the skipping stops, spin around on the middle, then take it back to the big ring. Shrug my shoulders and write it off to fine tuning the cable tension to the rear der.
Then on Tues I meet Butch for our weekly Lebanon Hills man-ride (our wive get together and ride once a week). I shift down to the middle ring and start to really stand on it as we ride out of the parking lot.
BAM! chain slips, knee slams into stem. whimper and try not to cry.
Looks like its going to be a big ring session at Leb. So I spend the next hour and a half talking with Butch about drive train wear as I staggered and wobbled around Leb in either 44:18 or 44:28 due to the skipping between the 21 and 24 cogs. In some ways I was tempted to just put the old chain back on and ride that drivetrain into the ground.
Some people may have a little angel on on shoulder and a little little devil on the other assaulting their self conscious about right and wrong. I have a little dirt bag (aptly nicknamed "scumbag stumpy" by a guide I used to work with) that sits on one shoulder and Alison sitting on the other. They debate on whether or not I should poach closed trails, eat free lunch at union meetings that I do not belong too, and generally debate the nature of my everyday existence. My mind is a scary place.

So on the drive home I caved to prudence, and stopped at Penn Cycles to get a new 32 tooth middle ring and a 11-32 cassette. Wasn't the caliber of stuff that I would usually buy, but I was not about to throw down 11o bucks on a 990 cassette to save 150 grams. I hate paying retail, but Penn was pretty reasonable.

I guess that I am now trying to figure out how much life I should expect out of a chain? I didn't think that I had a excessive amount of miles on the chain, but I also hypothesize that using solely dry, wax based lubricants on it my lead to premature wear. I like dry lubes (plus Scooby gave me a box of dry lube 2 two years ago after the Buffalo Mtn TT). I like how dry lubes keep things clean, but I am not sure if it lends itself to long chain lives. Chain wear is irrelevant when all my SS bikes have stainless cogs and rings. So I got some DuMonde lube, and am going to give that a whirl.

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