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Trainer Calibration - Yeah probably a lot to ask

PostPosted: Fri Dec 27, 2013 2:43 pm
by dannyst
Someone on my team pointed out a product available for the Kurt Kinetic Road Machine.

I read the review and it didn't really interest me that much, but I did get one takeaway from it. If I understood part of the author's point about it, the only thing that differentiates this power meter from the software based ones that are already available (eg Peripedal) is that their phone app knows how to do calibration to dial in the power for each session. He points out that the software ones are precise to within something like 10-20%, but with the calibration this thing offers, the power can be accurate back down to about the 1-2% range.

The article mentions that the calibration is done by doing an initial spin up to 23mph and then coasting to a stop, then repeating that after a 10 minute warm up spin. It apparently can figure out by the rate of deceleration from the flywheel, how to dial in and tweak the power curve for a given session.

I have wondered a lot if the small variables in how tight I synch the flywheel on my bike make some rides easier and others harder, thus making things like an FTP test a lot harder to make consistent. I also know that some friends on my team who are much stronger riders than I am have considerably lower FTPs according to Peripedal and their trainer. So it just got me thinking that it would really be amazingly awesome if the calibration was possible. I know it would be a gargantuan task to figure it out and set it up for every trainer you support. I personally think it would make sense to do something where you offer the calibration as an a-la-cart option for people to purchase their trainer's calibration. I don't know what price would be reasonable, but I personally would pay for something that would turn the software power into something as consistent and accurate as a true power meter. As a free update to the software would be even cooler of course :). I know that if you were to work this out, you would have a HUGE leg up on any competing program out there.

Re: Trainer Calibration - Yeah probably a lot to ask

PostPosted: Tue Dec 31, 2013 8:31 pm
by Adam
This would be awesome, but probably unrealistic to accomplish.

The Kinetic Inride has a significantly higher resolution than what I get from a bike speed sensor. The Inride gets a data point for every rotation of the trainer cylinder. I get a data point every rotation of the wheel, which is probably 10x lower resolution.

Unfortunately I don't think this would be possible to do reliably. If I ever do figure out a way, I would be happy to add it. Thanks for the suggestion!