I watched Stage 6 of the virtual TdF run on Zwift. Ineos’ team included Froome - the video of him on the bike/trainer was pretty spectacular - in the shade of a tree with a phenomenally attractive background. But it was totally apparent that he was running non-round chainrings. Actually, pretty extreme non-roundness. Now, maybe this is what he rode pre-crash, or maybe this is some compensatory effort to adapt to any residual effects of his injury.
More importantly (and more generally - I don’t care about Froome in the vTdF, or the vTdF overall b/c the charity and novelty/experiment aspect of this event clearly trumped the accuracy and fairness components)…do non-round chainrings provide any advantage/disadvantage in Zwift? Which is another way of asking how individual, controllable trainers/bikes ‘handle’ non-round chainrings. My guess is that this is known (certainly should be known by the trainer manufacturers, at least for commercially available non-round chainrings).
Just probing the ST hive mind about this and if there could be a way to design a chainring that provides some advantage in power reporting… Just to be clear, I’m NOT implying anything negative about Froome, just opening the discussion of the power reported by non-round vs round chainrings from Zwift-compatible trainers (and power meters, I suppose, such as pedal-based or other systems).
I watched Stage 6 of the virtual TdF run on Zwift. Ineos’ team included Froome - the video of him on the bike/trainer was pretty spectacular - in the shade of a tree with a phenomenally attractive background. But it was totally apparent that he was running non-round chainrings. Actually, pretty extreme non-roundness. Now, maybe this is what he rode pre-crash, or maybe this is some compensatory effort to adapt to any residual effects of his injury.
More importantly (and more generally - I don’t care about Froome in the vTdF, or the vTdF overall b/c the charity and novelty/experiment aspect of this event clearly trumped the accuracy and fairness components)…do non-round chainrings provide any advantage/disadvantage in Zwift? Which is another way of asking how individual, controllable trainers/bikes ‘handle’ non-round chainrings. My guess is that this is known (certainly should be known by the trainer manufacturers, at least for commercially available non-round chainrings).
Just probing the ST hive mind about this and if there could be a way to design a chainring that provides some advantage in power reporting… Just to be clear, I’m NOT implying anything negative about Froome, just opening the discussion of the power reported by non-round vs round chainrings from Zwift-compatible trainers (and power meters, I suppose, such as pedal-based or other systems).
I’d have to guess it shouldn’t matter on a direct drive trainer. Most of these events make you use the direct drive trainer power, not a separate power meter reading at an unknown location (pedals, crank, etc…). This makes it consistent, all readings at the trainer. Next, the trainer per the terrain (percent grade) likely just holds a torque on the rotating assembly. The faster you spin through that load, the more power it takes.
I haven’t used the Osymmetric rings but I use the Rotor QXL rings and I love them. I have heard that if you are using SRAM you can have shifting problems but I use Shimano and havent had any problems.
Yup, I knew that Froome was on Osymetric (or similar) previously, but watching him today, the variation in chain position per revolution seemed super noticeable. Maybe the appearance is just because we don’t often see him side-on, especially stationary.
I haven’t used the Osymmetric rings but I use the Rotor QXL rings and I love them. I have heard that if you are using SRAM you can have shifting problems but I use Shimano and havent had any problems.
I have used Rotor Q and QXL fine with Sram and Shimano but I couldn’t get Osymetric rings to work at all. They went on and came off my bike pretty quick and back to Rotor.