Tuesday, October 18, 2011

Techie Tuesday: Drivetrain Maintenance

After a rather nasty mis-shift, I've been trying to work a gremlin out of my drive train. I started by inspecting the chainrings and cassette gears for broken or bent teeth. I couldn't find any, so next I looked at the derailleurs, shifters and cables. I then inspected the frame route for the front derailleur cable, and found a problem.

Where the front derailleur cable comes through the frame there is a hole. Pretty stupid design, as it should clearly be a mtb style rubber seal, but there it is, and it was filthy and packed with sand, dirt and sticky dried oil and Gatorade.

Here's a nice video showing how to clean that hole and the thru-frame cable guide.

You should also clean the guides for both the front and rear derailleurs that run under the bottom bracket, as being at the bottom of the frame, they get fouled by Gatorade that spills on the frame and runs downhill.
Chain on biggest rings, shifters positioned to relax cables for max slack, makes for easy cleaning of BB cable guides. Note pedal tether to prevent shifting.
This is a big problem area, and monthly cleaning and oiling will make your shifting fingers much happier. A toothbrush is a great tool for cleaning the BB routes, as is a good terrycloth hand towel on the tip of a straight-bladed screwdriver.

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