eric wrote:Patterson is what got me to give up on 50x12 and buy a cassette with an 11t cog.
I also got popped on Patterson (E3) on a gradual descent with a tailwind. But I wouldn't have gotten popped had I not been at the back in the first place. And I wouldn't have been at the back if I hadn't descended like a wuss. I do mostly hillclimbs these days.... don't need to worry about that
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Anyway, the point the chainline on a 1x12 will be less optimal than on a 2x11 is still valid, however. Measurements published in Cycling Science have shown chainline affects efficiency much less (if at all) then one might expect. Indeed in the early days of road racing riders wouldn't use multi-gear hubs because it was felt optimized chainline was critical. Certainly the SRAM 1x11 works well: it won the cross-country world championship. But a key efficiency there is pulleys and chainrings which are specifically designed for chain retention, with teeth specifically mated to the wide and narrow gap pattern in the chain. Such chainrings wouldn't allow front shifting.
It's only a matter of time before we see a similar 1xN group for road. With a 34 or 36 tooth rear cog, you could even go up to a 50 front ring and still have a low climbing gear (50/34 is same as 39/26.5).