How does it feel/work?

[worldpax]

Wasn't sure how to search for this.

When you combine motor power with leg power, how does that work or feel?

Let's say I'm cruising along with no pedaling at 20mph and then I start to pedal without changing my throttle setting and reach 25mph. Effort wise is that going to feel like I'm pedaling at 25mph or 5mph. My guess is that it should feel like I'm pedaling 8-10mph when you factor in aerodynamic drag. Is it just a simple sum of watts?

I'm just making these numbers up as an example.

watts required to go 25mph=350
The motor provides 250 watts and then I add in my 100 watts of leg power which gets me up to 25mph.

Just wondering if I could use a smaller motor or a wind with more torque and use my legs to achieve the top speed I would like on occasion.

 

[Drunkskunk]

It feels seemless for a rear motor, Hills feel flatter, flat ground feels like you're riding down hill. otherwise, you won't notice a rear motor except for the slight sound.
Front motors are a little different, because you can slightly feel the torque pull the front in corners and turning sometimes, but in a straight line it's just as seemless.


You can get by with a smaller motor and just pedal harder, but that's rarely the best plan. You could easily over load and burn up a motor that way. Unless tthis is a pure race bike, its better to match a motor to the riding conditions, and then just add what ever level of pedal input you chose to add.

 

[d8veh]

It depends a lot on what type of drive you have (hub or crank), what the maximum speed of the motor is and how fast you're going.

Assume that you have a 500w or 750w hub-motor capable of 30 mph, and you're travelling at 25 mph with the throttle at a constant setting. You can pedal as hard or as light as you want. You won't see the speed change. Instead, the power used by the motor changes. You can see it if you fit a wattmeter. Most controllers use speed control, so your throttle or PAS sets a target speed, which the controller tries to maintain. If you're at maximum speed with the throttle against the stop, the bike is probably below the target speed of the controller, so the extra pedal power might add about 1mph to the speed. You can still pedal as hard or lightly as you want. With a speed control system, pedalling saves battery rather than increases speed, except when hill-climbing, where the extra torque from pedalling can make a bigger difference

If you had a low-powered bike (250W), you need to pedal most of the time. It;s a bit like pedalling with the wind behind you. In principle it's like I described above, but, because of the greater proportion of power coming from the pedals, its slightly different.

Some bikes, like the European, crank-drive ones, use a torque control system rather than speed control. They behave more like whay you're expecting because the motor torque depends on how hard you pedal.

 

[dogman dan]

For one, if you are motoring at 20 mph, and pedal to 5 mph, it feels like a lot more than pedaling 5 mph.

This is laws of physics stuff you can't avoid. Air drag at 5 mph is a tiny fraction of drag at 20 mph, and the drag when you increase speed to 25 is a lot more than 0-5 mph.

For this reason, you see similar effect on range of your battery. Traveling 25 mph, you might have 20 mile range. but slow to 20 mph and you might have 30 mile range.

For me, a normal person past his athletic prime, running the motor 15 mph, and pedaling to 20 mph is difficult but possible. I don't think I can add 5 mph to 20 mph. Not even in a sprint, since for me a sprint won't last 50 feet. Often the road will make it harder, with a tiny grade you can't see, but sure can feel.

If you are young and strong, able to put out 200+ watts for hours, then you will get more. But it's still closer to 300w more to get from 20 mph to 25 mph. At 25 mph you can easily be pulling 800w, when 20 mph was 400-500.

The way to run an ebike efficiently, is to pedal and take some of the load off the motor. Set throttle to 20 mph, then with a brisk but maintainable effort, pedal up 2 mph more. A wattmeter on the bike will show your effort to be about 150w. Or, if you wish, you can faux pedal. This 50w or so of spinning, just flapping the legs will not show on your bikes wattmeter. But just moving the legs for 30 min can still have a huge effect on your health, starting with better circulation. Spin long enough, and you are strong enough to pedal at 100w for miles, then 150w as your weight goes and lungs improve.

It's quite possible to ride an ebike to improve your health. It's also quite possible to stop pedaling and turn into a lump of grease. A wattmeter helps a lot, it keeps your pedaling effort honest.

Lastly there is the issue of gearing. If your top gear is 48-14, then by 25 mph you are clown pedaling. You have a very hard time maintaining a cadence fast enough to really push on the pedals. Clown pedaling is what you do when a cop sees you going 35 mph on your ebike. Pedal like a cartoon character, and he may not think it's funny you are going that fast. My cargo bike has a 56-14 top gear, and I can't push very hard past 25 mph.