Recently I'm pretty interested in Roll Road Emma3.0. It has a 1500w powerful Bafang motor. Since I living in hilly area so the motor is the first I would consider.
Yes. 20 is fast enough on the flats for sure. It's those big ass hills that get in the way. LolIn 2020 I bought a Radrunner after studying an EBR video that showed its performance. Mine was disappointing. I checked the specs: 750 W and 80 Nm. On a 10% grade I found that I was getting 2/3 of that torque. On a 6% grade I found I was getting 2/3 of that power. What's more, when I studied the video again, I calculated that they were getting much more torque and power than specified.
They claimed 750W and 80Nm because that's what Bafang specified for the motor output. Bafang must have specified a 25 amp controller. Radpower must have used 16 amp controllers for OE and 35 amp controllers for their demovid. With the OE controller, I would have had to push the bike up anything steeper than 10%. A 35 amp controller gave me ample torque and power.
That was a geared motor. I've also had three direct-drive bikes. The 750 and one of the 500s came with plenty of torque. The other 500 was from Radpower. I found that it was producing only 350 watts. As with the Radrunner, the OE controller was too small for the advertised mechanical output. A 25 A controller gave me more than 700 W output on a hill. For my purposes, the torque and power were as good as what I got from the 35 A Radrunner.
Air drag becomes significant at 15 mph and increases with the cube of speed. I don't go much over 20 on the level and am usually not over 15. I guess that's why if a motor can put out 700 watts, that's plenty, provided it can produce enough torque. Adding poles can increase the torque of a direct drive motor.
Here's what a riser did for me on my Radrunner. I'd say the bars were now 10" above seat level, which was typical of how riders adjusted classic 3-speed commuting bikes (although those bars had a better wrist angle).That setup looks painful. With no front suspension you feel everything you go over. Nothing to absorb the rough roads. I wanted my bike to be comfy as possible so I added a riser and Jones H bar to allow my arms to be higher up and back. Much better ride. Here's some photos.
so you figured the riddle of wide tires too,congradulations,used to drive a dump truck with "wide floaters" on the front, beat you too pieces.My Radrunner was terrible on bumps. At 30 PSI, those wide tires were stiffer than other tires at 60 PSI. A suspension post and seat with springs made little difference. A worse problem was that the handlebars were at belt height and not far ahead of my belt. That made my upper body unstable and thus the steering dangerously unstable.
It was much better after I moved the seat back to get it away from the bars. Comfort on bumps was an unexpected benefit. Instead of sitting erect, I was leaning forward, a bit like standing with my butt against a wall for stability. My legs were absorbing most of the bump energy, and they did it better than my spine.
Wrist shocks were still so bad that apparently I tore a tendon. It felt as if I had a broken bone in my wrist. It finally dawned on my that I could use a riser to raise the bars a few inches. Raising the bars meant less weight on my hands, and my arms were freer to swing on bumps instead of transmitting shock lengthways.
I also bought different bars to change the angle of my wrists. It still had stiff tires and no suspension but was now comfortable on bumps. My legs could lift my butt, and my wrists could "float."
The photo shows my position with the seat back 7 extra inches on a layback post, braced with a plywood triangle. Leaning forward to put weight on the pedals took the weight off the seat, and that meant comfort. However, these bars were too low, not letting my arms swing up to float over bumps.View attachment 181820
the floaters i refer too are those heavy duty 65 mph things that cost way more than an 11.00,things would beat you to death and when the alingment was bad these things let you know it.I retired from trucking in 2000. I pulled double tanker trailers that had those super single tires on them. Those things made me nervous. With dual tires, the second tire will keep the load upright. But blow a super single with 105,000 lbs. load and that liquid load could roll. Never noticed the lack of comfort, the tractor had normal duals. My bike has balloon type, not the fatties. Good ride.
The wide tire was suppossed to be lighter than the duals thus saving on fuel. The discomfort and worry to the driver was secondary. On bikes I fail to see the advantage of the fat tires.the floaters i refer too are those heavy duty 65 mph things that cost way more than an 11.00,things would beat you to death and when the alingment was bad these things let you know it.
as much as i dislike them they seem to be a bit better in the rough,i noticed my 27.5 bike handled better then the 26" bike with narrower tires on my "hell trail"( finally had to abandon it-its the only place i liked to ride around here,17 mile round trip) had a guy comment yesterday that the trail bikes have destroyed the road( part of the eastern trail) i agree.The wide tire was suppossed to be lighter than the duals thus saving on fuel. The discomfort and worry to the driver was secondary. On bikes I fail to see the advantage of the fat tires.