Really good that you have come on here and engaged with us - that’s great to see.
If I was going to offer any (unsolicited) feedback it would be around your statement on the 1% accuracy.
You will have found that nothing invites criticism quite like a power meter accuracy claim.
On your Kickstarter page I think you will receive more goodwill if you stated the accuracy more like a goal rather than a claim.
“We believe that a real-world accuracy of 1% will be achievable” is better in my mind than “CycleClick measures power within 1%” - the latter statement will arouse a lot of suspicion without the data to support it.
And just out of interest…. would it not be easier to directly measure the cadence and infer the chain speed (you would have to tell the unit how many teeth the chainring has)? Then your chain mounted unit only has to worry about the chain tension.
Finally…. I would sleep easier if the chain unit could be attached from the rear of the bike near the cassette rather than from the front mech…. it just seems to me the way it is attached now that it could be more prone to causing damage to the bike if it were to become dislodged or bind to the chain.
That’s doubly true on this forum: (the royal) we would like to see some actual data and more info how you arrived at this conclusion rather than just claims. If this thing works and is accurate and is cheap, I’d be happy. But even reputable companies (cough, Shimano, cough) have struggled to produce reliable power meters. Others (e. g. Rotor and SRM power meters) have some flaws such as problems dealing with temperate changes or indoor/outdoor rides despite > 10 years of experience.
Yup. I’d attach it like a chain guide or front mech.
It is also a swinging mass (from what I can tell, the thing rests on top of the chain) away from the points where the chain touches the sprockets (front chain ring and cassette in the rear). It’d exacerbate chain movement as far as I can tell. That’d also be alleviated if it were mounted like a chain guide.
Then you need an additional sensor somewhere else to measure cadence. That doesn’t seem easier to me?
I also think that you need to measure chain speed, and direction, because you don’t want to measure tension when the chain is moving backwards, or hanging a bit slack due to the position of the freehub.
I do wonder how accurate this will be over time, with increasing chain wear. And if different chain lubes affect it, eg wax on a cold day, when the rollers might not roll as easily.
“”We believe that a real-world accuracy of 1% will be achievable” is better in my mind than “CycleClick measures power within 1%” - the latter statement will arouse a lot of suspicion without the data to support it.”
Yes, I think there is a not so nice term for making claims in your marketing materials that have not been achieved and verified, and therefore have no basis in reality at the present time.
It isn’t just suspicion, getting this right is really hard even if everyone is doing their best. Like I mentioned above, even companies with > 10 years of experience in power meters can still struggle with it. The two exceptions that come to mind are Quarq and Assioma.
@Picklerickle mentioning IQ^2 is good, too. Even if everything is above board, if you post in a community forum like this one, you need to establish trust. And building trust here can pay off, because some amongst us might be crazy enough to try it out once they have been convinced that this is a serious effort to build a power meter.
Lastly, it is important to remember that even companies with a good track record can struggle. I have supported see.sense Kickstarter projects on three occasions. The first two went alright, the products shipped later than initially expected, but every time I did get what I backed. They have great support and I know that these are serious people with experience in bike lights. However, the last project seriously went off the rails and is >1 year late. So even with a good track record, through no fault of anyone, things can go wrong.
I think the right move there was to scrap the video. Publishing it knowing about an obvious issue that would both damage the reputation of your product and bring your companies skill into question whilst relying on “understanding” is naive.
Whilst you are correct it is used in other industries, you must remember that the giants of this industry also employ many engineers who have came from alternative backgrounds, including aerospace.
With their infinitely larger budgets and sizeable engineering teams, they have decided that this type of approach is a non-starter. As a small team of three, you should take a step back and ask why, if your method of measuring is common elsewhere, that it has not been done already.
There could be a market for something like this at the right price.
I’m not at all convinced that a 1% accuracy will be achievable in real world conditions - i’d be impressed if it managed 5%.
Also it looks likely to be heavier than other solutions - and will cause some drag on the drivetrain.
Swapping pedals really isn’t that difficult.
However, if this was under £100 I could be interested to give it a try. It would be an improvement on some turbo trainers. Could be a cheap way to add power to rollers. Also good for a casual cyclist to more accurately track calorie burn etc. Same power meter for all types of cycling shoes/flat shoes would be a USP.
But I’m not sure the stated price makes sense, not when you consider the price of a single sided pedal power meter…. and you get pedals included in that price
The power meter was mentioned in the latest Peak Torque video, seems like he would be very interested in taking a look at it if they are willing to send a unit his way.
What I would like to see is actual power files like DC Rainmaker posts of a defined test protocol (needs to include steady state efforts, 30-30 / sprint type efforts, and long duration for heat / drift) across the following configurations:
ERG mode stability: Big chainring, all rear cassette cogs (every other one would be okay, but need to include the largest & smallest) at varying cadences
As this is a chain based power meter, the intent of this is to see if chain angle / chain speed to power affects the power reading
Redo the above for chains with varying mileage: brand new, 500km, 1000km, 1500km, 2000km, 3000km, 5000km - again, does chain wear affect power reading
I don’t know anyone who has ever swapped pedals without buying a new bike. I’m sure some people do, but this is likely a very thin subset of the cycling population.
