Technology

#Your ebike doesn’t need a ton of power to be worth the price

#Your ebike doesn’t need a ton of power to be worth the price

Whenever I read a review of a lightweight ebike, inevitably someone in the comments feels the need to point out: “you can get the Powertron Cyclenator with a 1,000,000W motor for this kind of money!” Or, you know, something like that.

I’ll admit, when I first started to ride and review ebikes, I thought much the same. I’m a big guy, after all, and back then I had pretty much no cycling experience beyond just knowing how to ride a bike. More power for the money always seemed like a good idea. How else was I going to get up that one nasty hill?

But after reviewing a bunch of ebikes and riding and researching dozens more, one thing has become obvious: the power specs tell you little about a bike’s performance. They tell you even less about how much you might actually enjoy riding and living with a bike.

Let me make one thing clear: This article isn’t meant to disparage high-powered ebikes or even dissuade anyone from buying a high-powered ebike — they can be a blast, and you should ride whatever you want. If you’ve already tried out several ebikes, chances are you know what you want. I’m not here to judge you.

Instead, I’m aiming this at ebike newcomers. It’s my experience that many people buying their first ebikes aren’t used to riding a bike at all, so it’s easy to assume more power is automatically better.

This isn’t always the case.

Watts are misleading

The most common spec people will look at is an ebike’s power or wattage rating — perhaps because it’s one of the most prominent in marketing. You’ll see many ebikes rated at 750W in the US, for example, and some that claim even higher performance. Yet most of  the ebikes sold in Europe are limited to 250W. Does that mean that European ebikes are all weaksauce?

Hardly.

While an ebike might be nominally rated at 250W, this is usually given as a ‘continuous’ or sustained power rating; this is essentially how much power the motor is allowed to produce over a very extended period of time. However, the majority of these motors are capable of providing temporary assistance that goes far beyond the 250W rating; it is not uncommon for them to deliver twice that power output — or more — during a climb, for example. (For a more technical explanation of how this is possible, ebikeschool.com has a good writeup here.)

In my experience, this means a motor’s watt rating is a very poor predictor of the amount of assist a bike appears to be providing, especially when comparing across different types of motors. Sure, the 750W hub motors I’ve ridden generally feel faster than the 250W hub motors (not always!), but things get a lot fuzzier in smaller increments (say, a 350W motor vs a 500W motor).

It’s also a lot more complicated when comparing a hub drive to a mid-drive, which even at 250W often provide a ton of assistance (mid-drives are also more efficient because they can leverage your bike’s gears).

That said, some ebike companies do provide a ‘peak’ power rating, which should give you a better idea of what to expect, although it’s not definitive.

Torque is more useful, though still imperfect

A much more useful figure is the motor’s torque rating, which tends to correlate more with the feeling of having ‘super legs.’ You especially appreciate the extra torque when going up a hill, carrying cargo, or starting from a stop.

For example, the vast majority of mid-drives from the bigger, more reputable brands (Shimano, Bosch, Yamaha, Brose, etc) are all rated at 250W, but they typically differentiate their product tiers by torque rating. A cheaper mid-drive might only deliver 30-50 Newton-meters of torque, while heavy-duty motors meant for mountain biking and cargo will tend to pull 60-90 Nm.

Credit: Bosch