As I mentioned yesterday, I’ve been having some drivetrain issues with the AMPerino:
Specifically, under “load” (to the meager extent I’m capable of applying load to a bicycle drivetrain), the chain would defect from the middle ring to the grandparent ring.
After semi-careful examination I was unable to find any glaring defect that might cause this to happen. The shifters and derailleurs were adjusted properly, the chain was lubricated and didn’t seem to have any sticky links, and I couldn’t find any play in the bottom bracket or anywhere else that would be sufficient to move the chain off the middle ring. However, I did feel sort of a tick or click at a certain point in the pedal rotation, and somehow I came up with the theory that perhaps the issue was with the middle ring itself.
Trying another chainring was easy enough in theory, but the only one I had in the appropriate BCD was in use on my three-speed singlespeed:
I have been extremely pleased with the Roaduno in thringlespeed guise, and yet I continue to experience the urge to re-singlespeed it. This is the Curse of The Singlespeed: when you don’t have one you want one, and when you do have one you enjoy riding it so much you think about how it would be even better with a couple more gears. And the blessing and the curse of the Roaduno is that it’s very simple to set it up either way, or go back and forth, especially if you have lots of spare parts.
All of this is to say that borrowing the middle ring was just the excuse I needed to revert. So I removed the triple:
And replaced it with the original crank from the Normcore Bike:
And yes, you’re goddamn right I left the Biopace chainring on there:
The chain’s a little slack at certain points in the rotation but that doesn’t matter. You can really feel it Bio-pacing when you’re pushing up an incline, too!
Part of my thinking for using the Biopace is that Sheldon Brown says it’s good for riding at low RPMs, but mostly it’s because I’m a proud member of the Anti-Velominati, and Rule #1 is that you should always have at least one bike equipped with Biopace.
[Qui si parla Bee-oh-PAH-chay]
Next I installed the scavenged chainring on the AMP, and you won’t be surprised to learn that I was wrong about the chainring because the problem was still there. Could it be the chain? I swapped it for a 10-speed with low mileage and the derailleur threw it off the large cog and into the spokes immediately, making a mockery of my disdain for pie plates:
If you’ve been there you know it’s the equivalent of getting yourself caught in your zipper:
Fortunately I was able to extract it without the aid of first responders. Then I duly adjusted the limit screws, and while I’ve only test-ridden it around the neighborhood, so far the results are promising:
Though this sort of thing does make me remember why I started riding singlespeed mountain bikes.
