Comment on WeRide: Cycling community celebrates reinstatement of e-bike standard
Zagorath@aussie.zone 1 month ago250w limit in EN15194 is overly low
I just don’t agree. Remembering that that limit is continuous output, and brief spikes above that are permitted, and that a throttle-operated vehicle is illegal, so some power from the legs is always to be expected. I’ve got a power meter on my analogue bike, so I can tell you how much power my legs are putting out at any given time. A very light, easy cycle, my legs are probably doing about 100 W; that would be 350 W if you put the same easy effort with the battery of an ebike.
The most power I have ever put out for 2 minutes is 303 W. Bring it down to 1 minute and I’ve done 400 W. But that was during a power test on an indoor trainer. Even climbing up an incredibly steep climb, I can manage with about 500 W for about 30 s. Now, what exactly EN15194 means by continuous output is left vague, talking only about how the motor is thermally limited. It seems reasonable that 30 s might be an acceptable amount of time to exceed the 250 W continuous limit by 150 W…or for a cyclist to put out more than that miniscule 100 W.
Just for reference, here’s a 25 second section of my most recent ride on an extremely steep section:
Text transcription of salient points of the graph
Graph showing both power and speed over a 25 second section. Speed starts at just below 20 and quickly drops before levelling out a bit above 10 km/h. Power climbs from just below 200 to a hair over 500 W over the first third, then drops gradually to just above 300 W over the last two-thirds.
At 39:30 it’s exactly 350 W, and at 39:50 it’s 351 W. That’s 20 seconds above the limit I set, where the cyclist would only be putting out 100 W. And a cyclist could definitely do this section with less power than I use. I have a psychological thing where I hate going slow up hill (even if I’m fine cruising casually on the flat, and I actually go way, way slower than most downhill), so I put in more effort than most would.
The counterpoint to my reasoning is that I’m a fairly light dude, riding a carbon bike. A heavier person with a loaded cargo ebike would necessarily need more power than me. The riposte I’d give to that is that this is a route that roadies use for the sake of training. There are multiple alternatives that are less steep. And there’s still the option to just go slower, or put out more power from your legs. Still, all that aside, I would be ok with allowing up to 500 W for cargo bikes. A bike not towing children or lugging large amounts of cargo absolutely doesn’t need more power, but people should be able to take their kids to a weekend sport club, carrying their kids’ sporting gear, in a bike instead of requiring a family car. And they should be able to do that regardless of where they need to go. So 500 W, sure. There’s zero case for anything above that though.
Tau@aussie.zone 1 month ago
The continuous output is where average people actually want more power though, one of the main points of ebikes is to reduce effort from climbing hills. Most people are not going to be at your level of fitness or investment in cycling (in both the physical and mental sense) and just want to get places without needing a shower afterwards. I can see why you want to keep a purer form of something you have an interest in (similarly I think there is limited need for automatic transmissions outside of disability) but there is a case for more power if you want more people to be riding than driving.
Zagorath@aussie.zone 1 month ago
To be very clear: the case study I provided is on an exceptionally steep hill. Very few people need to climb something this steep, ever. The 350 W you get from a currently-legal ebike plus a lazy casual amount from the legs (I’m seeing varying numbers, but every number I’m seeing suggests that even a slow walk on foot uses significantly more than 100 W). And on a non-cargo bike, the sorts of normal hills many people climb every day on their daily commute can easily be climbed at a good pace at 350 W. Heck, at 300 W, even.
It’s not about investment, it’s about ensuring the power numbers stay low enough to reduce the potential for abuse. It’s got nothing to do with purity, and nor did anything I say provide even the vaguest implication that “purity” has anything to do with it. If it was about purity, I wouldn’t be starting from the standpoint of assuming 70% of the power is coming from the motor, or using 100 W as my presumptive minimum even when climbing. I wouldn’t have provided the evidence with data for why even for people who don’t want to put in a lot of effort don’t actually need that much power, and explained how the fact that my rides do contain more power are precisely because they’re an outlier.
Zagorath@aussie.zone 1 month ago
Sorry but, what part of everything I wrote makes any of this relevant?