Sunday, January 20, 2013

Bicycle Sprocket Growth: 13 by 2030



Graph of number of rear cogs on Shimano road sets

Still battling rhinovirus/cold, or what a knowledgeable doctor tells me may be "parainfluenza", I set about doing something, anything, other than laying around listening to myself cough. This yielded the first graph, above, which shows that once marketers and engineers formed their unholy sprocket growth alliance around 8, their upward march of more and more rear sprockets has proceeded at a steady clip.

More, it seems, continuous to be perceived as better, probably faster, and doubtless with higher margins and shorter lifespans as tolerances tighten and dimensions shorten. Where will it all lead, though? 

Adding a rear sprocket every eight or nine years

Surely, an ever-narrowing chain combined with an ever-widening rear spacing will hit some practical limit, in which someone, hopefully an engineer, scratches their chin and wonders aloud, in the hearing of other engineers, "Will it really make cycling better if we have 13 rear cogs in the year 2030?"

I surely don't know. I'm not psychic, not at all. For example, I'd like to say that I knew how it would all turn out when I bought my Lemond road bike, but I didn't have a clue. I just liked the bike. It has ten cogs out back and three chain rings up front, by the way. Perhaps one day, out near the end of the second graph, we'll look back at it, with the aid of perspective of our then-new super-efficient nanotechnology bottom bracket CVT gear boxes, and laugh at the crudeness of a stack of 10 cogs crowded between the dropout and the hub.

Or, on another hand, perhaps cog count is like PC processor speed, 11 or so cogs being analogous to 3 or so GHz. Which would lead us to divert from the cog growth path, and down an alternate route of ratio adjustment, the multi-core 11 cog, if you will. Instead of having a single 11 cog stack, perhaps 3 or more concentric or planetary multi-core cogs would achieve that ever-increasing number of "speeds" without requiring further chain narrowing or rear spacing widening. Multi-core in '24! 

It would be like those early "turbo" add-in boards for the IBM PC, raise your processor speed to untold heights, add these multi-core cog extenders, increase your speeds to 60!

I have wondered in this space before about how many speeds I really need, and will freely admit that my opinion varies between 1, 8, 21, 30, and points in between. However, in the context of market-driven cog growth, that is perhaps the wrong question. The right one would be: how many cogs do you want?

    

13 comments:

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    1. Ah yes, the traditional 3x3 9 speed configuration.

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  2. When I bought a bike in 1986 with 6 cogs on the freewheel, I really felt like I was somebody!

    Now, I have 8 cogs on my rear cassette, and I only regularly use 3 or 4.

    The rest are dead weight.

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    1. I was engaged in a keep-up-with-the-Joneses speed battle when I was a kid. First we had one speeds. Then I got a stingray with 3 speeds. Then my friend got a five speed, and it was all over with. He was two speeds faster than me.

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  3. Wherever we end up, if it's further developments in the rear cassette, or more advances along the lines of the nuVinci hubs, we've got a way to go before we catch up to Sheldon's 63 speed :)

    http://sheldonbrown.com/org/otb.html

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    1. Total speed count will be somewhat difficult to tally when we pair a nuVinci with an 11 speeds cog and derailleur, but we'll come up with something.

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    2. It's true, infinite options x 11 might break your chart.

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  4. I live in super-flat Chicago, and I seldom shift out of my middle ring (out of three up front), and on the rear cogset I'm most often sitting right around the middle there too. Occasionally with a nice tailwind I can go farther down the cogset, while if it's too windy I end up going up the cogset. When I lived in Georgia though, it was a different story. Riding my road bike up and down rolling hills meant I used a lot more of the cogset as well as the chainrings (dual on that particular bike). Riding my mountain bike off-road was a totally different story. I probably shifted the whole gamut of gear options there, although I think the large chainring remained largely unused except when I'd ride the mountain bike on the road. Off road that large chainring was largely useless. The push towards more cogs in the back seems dubious from an engineering standpoint. What do 11 cogs offer that you can't get from 9 or 7, except maybe a weaker wheel and chain?

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    1. I run through a pretty large number of combinations on the trail as well. Not ashamed of using the very low end to grind up the longer hills, the high end for blasting down those same hills, and the middle range for everything in the middle. The vastly different types of terrain, even overall general trend of increasing or decreasing altitude, might lead you to stick with one particular range on one particular ride. It's probably similar for elite road racers seeking to eke out the last watt at the last rpm on the last ten miles at a high speed, finding that Goldilocks combo that just spins. But I find somewhere around 7 or 8 x2 or x3 to offer more than enough choices on the road, with most riding done in just a very small number of combinations. It occurs to me that it's possible that if getting a good workout was the MAIN goal, then using LESS efficient and LESS comfortable combos at unfamiliar cadences or power ranges might add more to the workout, but that's not generally my personal main goal.

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  5. Nobody quoted Grant P. who wrote somewhere "seven is heaven, eight is great, nine is fine, ten is getting a little ridiculous but it won't kill you." :-) Myself, I am comfortable with 7 x 2 for most riding.

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    1. I do wonder if something like 7x2 would more or less cover it. Or 8x1 for the clean look of no front derailleur, but honestly the better ones are almost no trouble whatsoever, and perform their function so well that it's hard fault them. (except I guess on a downhill mountain bike where it appears that it's nice to be able to restrain that chain to one ring so it doesn't jump off)

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