EBikes - is torque a good predictor of how easy it will feel to go uphill? Electric bikes sometimes quote the torque or max torque of the motor being used.
So for instance this bike has a Shimano Steps E8000 motor the torque of which is given as 70 Nm (confusingly enough the web page actually has another specification of torque for the same bike but let's ignore that for the moment).
Ignoring other variables for a moment (bike weight, battery charge, wind etc) would this bike go up a given hill at a given speed with less effort on the part of the rider than another bike with a quoted torque of, say, 90 Nm ?
If torque isn't a good measurement of &quot;effort uphill to achieve given speed&quot; what would a good metric be ?
To be frank, I would not put much stock in quoted ratings for motors.
Before I bought my electric bike, I test rode something like eight or nine different makes and models, equipped with a range of different motors (Bafang, Bosch, Brose, Yamaha, maybe some others), some with mid-drive, some with hub drive.
All of my test rides included some steep hill climbs.
The biggest difference I noted was that bikes that had a throttle were the easiest to go up the hill, and this was simply because it was possible to go up the hill with no pedaling at all.
Among the bikes that required pedaling for motor boost, there did not seem to be any direct relationship between quoted motor torque and perceived boost. I attribute this to there being too many variables involved.
For example, even within one particular line of bikes equipped with Bosch Performance CX motors, there were options for the gearing (Nuvinci, now Enviolo, vs Rohloff) as well as options for max speed (in the US, 20 mph vs 28 mph). The difference in gearing, as well as motor setting for the max speed, meant that even with the same nominal torque rating, different bikes climbed hills differently. For example, the 20 mph bikes were better climbers than the 28 mph bikes.
That said, all of the bikes made all but the steepest hills effortless to climb (up to the maximum speed rating for the bike), and even on the steepest hills I could easily double my speed as compared to riding a conventional bike (e.g. a hill I'd normally take at 4-5 mph, I could go up at 8-10 mph on an electric bike).
These tests were ridden entirely on paved surfaces, in a city where the steepest hills are about a 20% grade. Most of the test rides were in neighborhoods where the steepest hills available to me were in around 10-15% grade. Below 10% grade, most of the bikes provided enough power that I could reach the bike's maximum speed going uphill; the main exception being the 28 mph bike that I tried, which didn't have as much power going uphill as the other bikes.
Beyond the fact that the quoted torque for a motor won't tell you very much about how that bike compares to another, I will also suggest that you probably shouldn't care very much anyway. There is a vast difference between climbing a hill with an electric bike as compared to a conventional bike, and only very minor differences in effort climbing a hill comparing one electric bike to another.
In addition, there are a number of other aspects about an electric bike that IMHO should take much higher priority in terms of selection, including battery size and cost, drive configuration (mid- vs hub-drive), motor controller (I found the cadence-sensing motors very annoying, and the torque-sensing motors very natural to ride), and of course cost. And those aspects are overshadowed by the most important, which is simply how the bike feels to you when you ride it. How do you like the handling, how comfortable is the rider position between seat and handlerbars, etc.