Why you need a power meter
And why biking uphill is not hard
And it’s nothing to do with e-assist. It really does not have to be hard riding uphill. You simply have to go slower. And knowing your power output is the key.
As long as you output the same power going uphill as on a flat road, it is not harder going uphill. At all. Most of us find that difficult to believe before riding with a power meter. So for that reason alone, I recommend getting a power meter on your bike. Also if you don’t “train on a bike” but just want to enjoy riding.
Power meters have been all the rage for sports cyclists for a decade now - fueled to a large degree by TdF commentators talking about nothing but watts each summer. And when they get fancy they talk about watts per kg.
After designing and testing many different power meters my approach to it is a bit different - maybe also because I am not a sports person. The way I use the power meter is simple: By looking at the numbers on normal days in flat terrain where I feel comfortable I understand my comfort-watt level. And this is the level I try to not go much over for too long. Easy - not complicated :)
Touring
When touring the power meter turns into a calorie counter. Not for losing weight, but for gauging the riding limit for the day. I know pretty well how many MJ I can put into the pedals in a day if I want to be able to do that again the next day and the day after.
So when we do longer tours the power meters on the bikes are super valuable to set the ambitions for the day. No reason to overdo it - there is another day tomorrow. And it is supposed to be fun.
We simply note when we cross our personal 50% calorie limits for the day, which typically happens in the middle of the day. By looking at the route and the distance covered it is quite easy to figure out where to stop for the day - and to plan accommodation.
Need a video?
The YouTuber Cycklingabout (who we ran into at Eurobike last year when hanging out with the Pinion folks) made a long video explaining this and a bunch of other things related to getting the right gearing and such.
Riding naked?
Some prefer riding naked (= without a bike computer). I like having some numbers to look at on longer tours. Not with my head down in the numbers, but more as something to glance at from time to time.
But what numbers? For touring the typical speed and average speed (km/h) is not working for me.
Power instead of speed - or watts instead of km/h. The speed is what it is. It is a result of the power I put into the pedals and a bunch of other parameters I am not in control of. Like inclination, wind, surface, etc. So power is on my screen - speed is not. In staying at a sustainable level for an enjoyable tour, the speed is irrelevant. Power is what matters.
Total km traveled today is also relevant for me as the distance is what road signs show. This many km to the next town, etc. But even more important is the total calories (or Joules for me). This is what tells me what I put into the pedals and when it is time to stop for the day.
Fun fact: The number of joules put into the pedals is about the same as the number of calories burned by the body. The efficiency of the human body in converting energy-in, to energy-out is about the same as the conversion factor between joules and calories.
What about e-bikes?
With hub motor e-bikes, there is a significant challenge going uphill. Those electric motors do not output much at low RPM. Our friends over at Grin have this magnificent calculator: https://ebikes.ca/tools/simulator.html to help you figure that out. Before you build your dream hub-drive e-bike.
A mid-drive e-bike is a very different story as you can better use the gears of the bike with a mid-drive.
Power meter on an e-bike?
Is there a case for having a bike power meter on an ebike? Well, maybe. A significant number of new ebike buyers are supposedly converting their commute from public transportation towards ebike. Because - and here it comes - they want to get more exercise. And even though it sounds contradictory, getting an ebike can very easily be a way to get more exercise - not less - if the alternative is bus/train.
We see some ebike companies trying to power meter/calory counter in smartphone apps etc. With the type of super accurate, yet inexpensive ebike torque sensors we make in Sensitivus, we can easily build a power meter that is a LOT better than the (quite expensive) power meters available for sports/training purposes.
The sensor accuracy and sample rate are simply much much better than what we did back when we developed power meters. I am super curious to see how this surprising difference in the technology used in these two quite similar sensor types will merge in the future. Time will tell.
Happy pedaling (uphill).
NERD/TECH/BIZ STUFF
An open-source power meter?
Over at Sensitivus, we developed power meter technology and even had it on Kickstarter back in 2016. One of the few (if not the only?) power meter Kickstarter campaigns that actually delivered a product. With the average delay and all - but it DID in fact deliver the promised products :)
We also sold this technology to a number of brands and got it integrated into various cranksets. It is actually still selling in what is maybe the top power meter crankset you can get: The €2300 sub 300g THM Clavicula.
Problem is - volume is low. Too low to keep a sustainable business running around it, so it is hard to keep the technology up to date. It is still a really great power meter technology. And if we were to add some of the tricks we have developed for the e-bike torque sensors it could be even better :)
Should we open-source it?
In running development around this type of technology, you need a team with a combination of these types of skills (all at a pretty high level - this stuff is not easy):
Embedded software development (nRF-type ARM processor with code in C for running the complete system with ANT+ and BLE communication)
Embedded hardware development (low power, quite compact, and with some very sensitive signals/high gain)
App development for iOS (Apple)
App development for Android
Cloud management for the build system, user data upload, and firmware download site (encryption protected firmware can be downloaded into the PM through the app).
PC software development for calibration system where all PM’s are calibrated in a semi-automated test setup (.NET software under Windows)
Mechanical design and FEA skills to design what is in essence a load-cell in a weird shape (i.e. some part of a crankset)
Project management (and/or community management in an open-source setup)
Some of it could be outsourced, but you simply need a sustained effort on especially the software side to run this as a business.
So what do we do? And one idea is: Turn it into open source. Find a core team that want to drive this for fun. And honestly, it is great fun to play with this type of technology. But, here is the key question:
Can we find a team of enthusiastic engineers and bike crazies who want to continue the development of this technology into the very best power meter out there? Or whatever goal that team wants to set?
Would it be cool to have an open-source power meter that can be built at a really low cost? We once estimated the total Bill-of-Materials cost could be as low as $6 in really high volumes. I think that largely still holds. For high volumes. As the cost-adder on top of the crankset. For the materials needed. Strain gauge and electronic components. Which is what we call BOM :)
You can already go DIY
Since mid-COVID, we have offered the electronics as a DIY option for those wanting to tinker with the technology. This is still happening and is proof that there is a pretty good overlap between tech-savvy and bike-crazy people. Good - we are not alone :)
So, let me know?
Would you be interested in joining a team that takes over all the software and hardware design needed to build a real shipping power meter? And create a thriving team and community around it that can take it all to the next level? In exactly the direction you can agree on… No strings attached.
Let me know!
And also let me know if you think this type of technology can have a happy life as open-source? Or why that is a bad idea? I am very openly really unsure if this could fly without me putting in a lot of the time I don’t have.
Or is there another - even better - idea for this?
EBIKE/STAT STUFF
Is it more dangerous to ride on an electric bike?
No - not according to this new study that simply explains how
“greater fatality risk can be attributed to rider age and distance of travel”.
Controlling for age seems quite important when doing statistics on bike incidents. Who would have thought? Doh.
FUN/SILLY STUFF
Don’t know about you, but the things YouTubers do to have some “content” is sometimes a bit. I don’t know. Too much?
I have met Ray several times and actually consider him a great guy with high standards and good judgment. But here I have to ask: What’s the point?
FRIENDS
Oliver Bruce
We were at this Ethiopian restaurant after a long day at Eurobike in Frankfurt. Oliver was sitting across from me and before long we were deep in some great discussions over a few beers and some excellent food.
Turns out Oliver has a great grip on - and is quite sharp when it comes to the intersection of business, micromobility, and technology.
The reason I share this is that he co-founded the micromobility podcast, newsletter, etc. This is something you should follow if you are interested in that space. This also led to the forming of the Micromobility conferences - with the next one coming up in Amsterdam in June.
I do not plan to be there (although I would love to) - but I do plan to be at Eurobike again (maybe my EB number 11?).
ABOUT
I have been spending the last 10 years on sensors and technology for bikes. Both are things that I really enjoy. Technology for bikes can be many things - these are the types of products and technologies I can talk about from experience:
Power meters (to measure how hard you pedal for training purposes - but actually valuable for much more than just that). A product with a high retail price and a low BOM price. Mostly sold as after-market.
Case: Technology still on the market by THM - The Clavicula PM crankset.Brake sensors (for optimizing MTB downhill performance). Very niche product for elite riders, which may eventually slowly become more widely accepted. Pure after-market.
Case: Technology on the market from BrakeAce.
e-bike torque/cadence sensors (to make e-bikes feel more like “analog” bikes on a really “good leg day”). Super high volume product with a fairly low sales price - a pure B2B product for integration into a motor design or similar.
Case: Technology on the market from Sensitivus, but not quite out in stores yet.
Each of these examples has occupied a good chunk of my life over the last 10 years, but there is more. A lot more. This is a story for another day.
P.S.
Over on EE-Training I have a super nerdy course coming up - check this out if you are into designing the very fastest and most efficient digital bords today:
Signal Integrity w/Hands-On Simulation, Online, Apr 15-19, 2024
Find it all on ee-training.dk
P.P.S.
If you found this interesting there is more in the back issues. And if you found it boring, maybe the previous issues were more interesting for you:
Why you should buy a new bike now - and why you should know TwoTone :)
Why you should ride a bike to work - maybe even an electric unicycle
Why hub motors are better - and how Miri may be just the writer/photographer you are looking for
Thanks for reading along :)
[[ LET’S KEEP UNF***KING THE PLANET - ONE EBIKE AT A TIME ]]