I have been enjoying the heck out of my newly rebuilt LOOK KG486. There is nothing like a “new bike” to re-motivate (actually, the frame is 10 years old and most of the components only one year younger)—in the five weeks since I picked it up from the shop I’ve logged just over 1,000 miles on it despite it being the dead of winter! I don’t think I’ve never been as ga-ga over a 10-year old bike. From the beginning, however, I noticed trouble with the drivetrain. I already knew the chain was worn, and since I would need to replace it I also decided that a new cassette was in order—something with gears more suitable for flatland terrain rather than the old Shimano 105 12-27t cassette I had gotten for my latest trip to France and had slapped on when the previous cassette had worn out. I ordered up the chain, paired it with a 12-23t cassette (both Ultegra—no sense in paying top dollar for expensive Dura Ace components that will only wear away), and anxiously awaited their arrival. In a few days, I had them on the bike, hit the road to enjoy my new lease on a crisply functioning drivetrain, and CRUNCH!!! I hadn’t even thought about the chainring also being worn, but when I looked closely its teeth looked suspiciously small. The next several days confirmed the problem—no chain slip in the small chainring no matter how heavy the load, but whenever I was in the big chainring I had to really take it easy, or else CRUNCH!!! I ordered up the new chainring (and a small one as well, no sense in mixing old and new), and when they arrived I took of the old and this is what I found—teeth worn to nubs! I guess I can’t complain, since I probably logged around 40,000 miles on this chainring (for what it cost to buy a new one, that works out to about 1/5¢ per mile).
I had a bit of a scare when I was taking off the chainrings. The first four bolts came off fine, but the fifth just spun around as I turned the hex wrench—the nut spinning freely along with it. Now, it’s been a long time since I’ve changed a chainring, so I had forgotten what to do when this happens. I jumped on Google, looked it up, and found out that I needed a chainring wrench to hold the nut in place while I unscrewed the bolt. Great—now I have to wait until tomorrow, go to the bike shop, and buy a chainring wrench before I can ride again. I decided to go out to the toolbox and look for something… anything… that might serve as a chainring wrench in a pinch. As I was fumbling through the toolbox, what do you think I found? A chainring wrench! I don’t remember ever buying it, but I was sure glad I did. That problem solved, it was a quick matter to remove the last bolt, switch out the new chainrings, and voila… a “new” bike with brand new chain, chainrings, and cassette. Check out the teeth on the new chainring below!
© Ted C. MacRae 2015