But first, a quote from Sheldon Brown:
“Seven sprockets enough? More sprockets must be better, right? Not necessarily! The trend toward more sprockets is driven largely by spec hype. Two chainwheels and 7 sprockets can provide everything most cyclists need. Still not enough? A third chainwheel adds much more than an 8th, 9th or 10th sprocket.”
Today I think you could add 11th sprocket to that without changing much. To the minimal extent that 11-speed changes the game, you must counter with the downsides of the Herculean effort that made it workable:
- expensive chains with counterbored side plates
- still-narrower sprockets and pitch
- a new shift ratio, front and rear, incompatible with old gear (i.e. low-cost gear) still on the market
- new rear hubs (old ones being incompatible)
- even more extreme dishing of the rear wheel, sometimes ameliorated with asymmetric rear rims or wider OLN distances in the case of disc brakes
- expensive, short-lived, polymer-coated cables (and other friction-reducing doodahs such as ferrules with tongues)
- STI lock-in (no indexed down-tube shifters)
- and no doubt others.
So, seven speed.
Shimano 7-speed cassettes have among the most rational tooth-counts of any they have made. You can get almost any largest sprocket you desire without having to waste gears on 11T and 12T cogs at the other end. Here are some varieties of the CS-HG50-7 in ascending largest sprocket:
13–26 (13, 15, 17, 19, 21, 23, 26)
12–28 (12, 14, 16, 18, 21, 24, 28)
13–28 (13, 15, 17, 19, 21, 24, 28)
13–30 (13, 15, 17, 20, 23, 26, 30)
14–32 (14, 16, 18, 21, 24, 28, 32)
13–34 (13, 15, 17, 20, 24, 29, 34)
Although these cassettes may have been taken for granted when they came out, they are refreshingly practical when compared to today’s plethora of touring cassettes … all starting at 11T. Look at the relatively close ratios on the 14–32T despite its mere 7 sprockets.
I can think of some notable benefits to 7-speed over even 8-speed:
- even greater sprocket pitch but the same derailleur shift ratio, a combination that provides greater wear tolerance in cables, shifters, and derailleurs
- slightly more cable pull per shift than 8-speed, which itself has more than the new 11-speed pull, never mind 9- or 10-speed shifters with their proportionally shorter pulls
- less flange offset on the rear hub, allowing less dish and higher spoke tension on the left side
- better chain angle because the cassette is narrower
- more heel clearance with the narrower OLN distance
- potentially narrower Q-factor and better pedal clearance in corners.
To make this work you would need:
- a frame with 126 mm spacing. That means an old one or a custom-made one if you don’t already have one. You may have other reasons to order a custom frame anyway (I do)
- a hoard of cassettes in the flavours you’re likely to want. I have settled on the 13–26T in 8-speed so the same in 7-speed (which is only missing the 14T) sounds like a good option to me. These are still pretty cheap, because Shimano still makes them. That won’t last forever, hence this stash
- shifters. This isn’t a problem if you have freed yourself from the tyranny of STIs. There are many NOS indexed down-tube shifters on eBay. No doubt bar-end shifters are also available. These are durable, so a pair a decade should do. Besides, friction shifters are an option. STI shifters may also be viable
- a couple of 126 mm hubs and preferably some spare cones. NOS Shimano 126 mm hubs on eBay are still nearly as cheap as new 130 mm hubs, so this doesn’t pose a large problem.
- chains. They are identical to “8-speed” chains that are still widely available, but 9- and even 10-speed chains are likely to work also
- derailleurs. Anything works at the front, and any 7-, 8-, 9-, or 10-speed road derailleur (and many MTB ones too) work at the back. Thus compatible derailleurs are also likely to be available for a long time to come.
Why not 5- or 6-speed while we’re at it? Maybe, but parts availability does not make this an economical exercise and Shimano’s freehub design has advantages. Besides, at those sprocket-counts you may start to feel the lack of ratios by comparison to modern standards (although that hasn’t prevented a revival of fixed-gear bicycles).
Have I missed anything important?
