I recently added a DZero (barely used) to my stable of PMs and the results were interesting upon install. For some reason it took 3-4 rides to fully "settle," which isn't something I'd expect on a spider-based PM where the chainrings haven't been touched since they were taken off the previous owner's bike. Nonetheless, the first time I performed a zero offset on the DZero it returned an offset of 197. I immediately zeroed again, and it returned 192. At the end of the first ride, I zeroed once more and it returned 217. Before the next ride, I got 216. In the middle of that ride I backpedaled 4x and checked the offset again...208. On the 3rd and 4th rides, the offsets were identical at 220 and the power numbers were finally within 1-2W of my Vector 3s.
Very odd. I wonder what was settling exactly, the NDS crankarm + GXP bolt interface??
I did check the torque on the chainring bolts, and everything was plenty tight. I did not check the 8-bolt DS/spider interface, but maybe I should have. Anyway it seems fine now, so it probably wasn't that.
Crank based power meter questions
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It depends on the power meter. Some PMs will always display 0. Some PMs will display an actual offset value. Some PMs will just display the real-time torque in newton-meters, which should basically be zero.
In the case of Quarq, it shows an integer up to +/-1000, which corresponds to a static N-m offset. The Qalvin app will show both.
Interesting. The Assioma Duo's always display 0 when they are calibrated without any weight (crank vertical in 12/6 oclock position). They'll show a torque value if, for example, you do calibration process while pedals are weighted...TobinHatesYou wrote: ↑Sun Dec 09, 2018 11:52 pm
It depends on the power meter. Some PMs will always display 0. Some PMs will display an actual offset value. Some PMs will just display the real-time torque in newton-meters, which should basically be zero.
In the case of Quarq, it shows an integer up to +/-1000, which corresponds to a static N-m offset. The Qalvin app will show both.