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Old 03-12-13, 12:21 AM
Tandem Vincitur
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Join Date: Sep 2005
Location: Northern California
Posts: 3,317

Bikes: BMC Pro Machine SLC01, Specialized Globe, Burley Rock 'N Roll tandem, Calfee Dragonfly tandem.

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Originally Posted by Turbotandem View Post
If Ritterview or Waynesulak could put the gearing in terms of cadence I think it would be more clear. What I get is this. At a given speed, let's say 18mph at a cadence of 105, right at the point you want to shift up. On the waynesulak gearing your cadence drops 10 counts to 95 rpm as you shift in to the next higher gear. On a Di2 gearing, like mine, you drop 12 counts to 93rpm. I have trouble believing 2 counts rpm difference is really making or breaking any team's power. Ritterviews charts are unlikely to distinguish 2 points of Rpm. Seems like a lot of analysis leading to the wrong conclusion, that you must have those couple points rpm....
Well, gear-calucator has several choices (see drop down on screenshot). For this comparison of your shift-like-butter Di2 double and my rheostat 33-speed triple I've chosen ratios. Does this help? I still see that the one on the top has large jumps!

I use the road bike racer authority to get away from the over-analysis. There is a free market, as it were, in gearing for road racing. If the simplicity and weight reduction of a single chainring racing road bike were worth the inefficiency of widely spaced gearing, then it would have been adopted. It has not been, even though that scenario would eliminate the FD, chainring, bolts/spacers and left shifter for much higher relative weight and complexity reduction in comparison to ditching a triple on a tandem. I go to a race, and I see it not. When I see bike racers with single chainring, then I'll start to think about maybe a double on our tandem.

So, I am immune to all this rhapsodizing about Di2 wonderfulness if it comes at the price of a double. As does the Keystone State electorate to their firearms and creed, so too will I cling bitterly to my cables and granny.

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