On Vestigial Gearing and Its Evolutionary Implications
How do you know when you've got gears you don't use or need? It's a tough call. Some might even say there is no such thing as "gears you don't need," especially when it comes to those low-low-low ones. If you can set up your bike with a sub-(sub)-1:1 gear, go for it! And even if you usually don't use them, you never know when they might come in handy, so better save them for a rainy day. I mean, who knows - you might go on a long trip where all the climbing comes at the end, when you are already right and truly exhausted. Or you could be called upon to rescue a cat from a tree.
Anyway, that has been my take on it at least. Which is why, even when I stopped relying on the biggest cogs in my SRAMpagnolo drivetrain on a regular basis, I kept them. Just in case!
...Until one day, I lost use of them completely. I am a little embarrassed to admit this, but hey - I never did claim to be fastidious when it came to bike maintenance. But anyhow, at some point my chain started skipping whenever I would try to get in the big cogs. Adjusting the derailleur didn't fix it, and it was that particular flavour of skipping, where I could tell the cable needed to be replaced. But I procrastinated. And procrastinated. And in the meanwhile I simply didn't use those 3 biggest cogs that were problematic. And hey - it was winter, so I didn't go on any long or overly hilly rides anyway. I would get the drivetrain fixed before spring came.
But spring came, and I procrastinated still. I started doing longer rides, steeper climbs, all with the malfunctioning drivetrain. In short, 4 months went by while I rode without the use of my lowest gears. And I didn't miss them.
Looking at my drivetrain one day, I realised I was essentially lugging around three "vestigial" cogs. And an unnecessarily long-armed derailleur that was installed specifically to accommodate them, into the bargain. Now: If I had managed to make do without them for this long, while doing rides incorporating the steepest climbs around, exactly what was I saving them for?
I examined the SRAM cassette to remind myself what gearing I was in fact using. To my surprise, the biggest three cogs were 36t, 32t and 28t. Whoa. That meant the biggest functional cog in the cassette was a 25t. So really I was using a 7-speed 11-25t cassette to do all those climbs, except with a lot of extra weight attached to it. I believe the technical term for that is: Jayzus!
So... I don't know. I am not going to go as far as switching to a racing cassette. And I still believe in stashing some "just in case" gears. But I think that the 12-29t cassette I had on my original all-Campagnolo drivetrain will be quite sufficient in that respect.
As mentioned in the previous post, I am dismantling my roadbike to have the frame painted. And when I get the frame back, I am going to re-assemble it slightly differently. Namely, the bladed-spoke wheels (which I have already given away) will be replaced with something more crosswind-friendly. And while I'm at it, I also think I will go back to my original all-Campy (sorry: "Campag") drivetrain, with a standard "rear mech" and "sprockets," if you know what I mean. It's a little sad to have finally achieved a perfectly functional hybrid sub-1:1 drivetrain, only to get rid of it 3 years later. But hey: Use it or lose it. It's evolution, baby. (Now: if anyone local needs an X9 derailleur and a 11-36t cassette, give me a shout.)
Do you ever discover "vestigial" parts on your bicycle? I am curious what they are, and what you do about it!