Friday, January 10, 2014

Sky switch from SRM to Stages

When you think about power meters what professional team comes to mind? Only one...

Indeed, there's a web site devoted to photos of Chris Froome looking at stems. Staring at his SRM display, many have claimed. Sucking the humanity of out racing by reducing it to pre-programmed efforts determined by power analysis? Hardly, obviously, but traditionalists always oppose change.

Froome and his SRM

He even does it in Pro Cycling Manager, a video game:

Froome and his SRM

So it's a major change in the world as we know it when it's leaked that for 2014, Sky is discarding their trusty SRMs for Stages power meters:

Stages on Sky

Stages measures power on only the left leg, assuming the right leg is the same. This, not surprisingly, results in errors. I looked at Stages power data in this blog post.

For example, comparing Stages power / 2 to Vector left-leg power is a good match, according to DC Rainmaker's data:

Stages on Sky

But compare it to the Vector right leg data, and things get uglier:

Stages on Sky

It typically takes two legs to pedal a bicycle (although some manage rather well with just one: Stages would be a great option for half of them).

I'm surprised the team of "marginal gains" would allow itself to get by with anything less than the best. In particular, since asymmetric chainrings are popular with the team, I'd be tempted were I them to use Power2Max power meters, which measure detailed cadence and can thus deal with eccentric chainrings. I looked at the error from eccentric chainrings in this post.

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