Rotor new 1X13 road drivetrain

[Tony]

I like Rotor as a company and think this will be a hit for the them if all works great in ride reviews. However no one ever mentions watt losses due to cross gearing on 1X systems?
https://road.cc/content/tech-news/244867-video-first-look-rotor-1x13-all-you-need-know-about-rotors-latest-hydraulic

[Jaybee]

Interesting that you have to run disc with 13sp. Also interesting that you can switch to 12sp and use an existing 11sp Shimano splined wheel (disc or rim)

Since I'm not gonna do the research myself, how bad are the power losses when cross-chained?

[Mark McM]

Interesting that you have to run disc with 13sp. Also interesting that you can switch to 12sp and use an existing 11sp Shimano splined wheel (disc or rim)

From the linked article (bolding added by me):

The reduced dish of the wheel means that Rotor is only offering the new hub as a disc brake system, because they’re not convinced the final wheel would be stiff enough not to rub on rim brakes. Anyway, the Rotor Uno shift levers, which are repurposed for this new groupset (minus the left hand shift mechanism), are disc-only anyway. The new 13-speed hubs have a 2:1 spoke ratio on the rear (24 spokes with 16 on the drive side) to increase stiffness.

2:1 spoking helps equalize spoke tensions, but it actually decreases stiffness unless the left spoke flange is moved outboard. Many hubs designed for 2:1 spoking do in fact move the left flange outboard, but this can't be done for disc brake hubs. As Rotor readily admits, these wheels won't be as stiff, which will affect handling, and may increase the tire/frame clearance required to prevent tire rub (i.e. may reduce the maximum tire width that may be used with a particular frame).

Since I'm not gonna do the research myself, how bad are the power losses when cross-chained?

The cross-chaining will result in extra drivetrain losses, but not by as much as that 10 tooth sprocket will. Here's an article about shifting strategies to decrease drivetrain losses, factor in sprocket sizes and cross-chaining:

https://www.bikeradar.com/us/road/gear/article/friction-facts-free-speed-from-proper-shifting-44016/