Frustrating lurch of e-bikes
 

If this has already been discussed, pardon me.

From time to time, I have ridden with people on e-bikes. For those of us who power our bikes the old fashioned way :), I find most people like consistency in the speed of the group - whether it's 2 people or 22 people. I have yet to ride with someone on an e-bike where they are riding a 'consistent' speed. They seem to be lurching often when they 'punch the gas'. Yes I know that 'consistent' is a relative term when it comes to hills, wind, other riders, etc. But I must confess, it's not a pleasant ride with this going on. For those of you who ride e-bikes, do they all lurch, or is it just the people I ride with???

It is the rider not the bike. They are using to much assist, sort of like pedaling hard then backing off. They need to learn to be smooth.

This has been discussed to death. Don’t need more criticism here than there already is. Close this thread

It's more difficult to be smooth on an ebike but I agree it depends on the rider. Of the three who regularly ride with our group, one was always smooth and still is. The other two were squirrels on regular bikes, still squirrels on ebikes. All of them tend to drop off on the flats due to the speed limiters, then catch up on the hills. It's still fun to see them cruise by on the hills, laughing and trash talk.:thumb:

When an automation company I worked for built a test skid for Fallbrook in Austin we went down there to test it out. At lunch they let us ride their e-bikes equipped with their CVT hubs. They thought it funny to not tell us and turn the pedal assist to 100%. I could totally see someone not totally familiar with the operation and use to have some bucking or surging.

They'll get used to it eventually.

Some ebikes, like my 500W geared rear hub drive from a kit, have somewhat crude pedal assist. I set mine up for 5 levels of power assist. It goes roughly 10, 15, 20, 24, 28 mph in each level.it acts like cruise control in an auto, only with 5 preset speeds, instead of being able to set any speed as in an auto. So some ebikes don't have the ability to tweak their speed to match group speed. Ebikes like mine could stay at the rear, and fall back and catch up at will so as not to disrupt steadier speeds of human only powered cyclists.

part of it is also hub drives were mostly they will go to the speed set for that assist level. when I test road one I was peddling my usually 80 r-ms but the bike kept going faster and faster till it topped out at that assist level. yes you can adjust this on some bikes but its not like a mid drive or a regular bike.

Might be that they are in higher gear ratio than the others since they have some assist and when they decide to accelerate simply accelerate faster since they have more power to put into that ratio.

Have you noted if they are normally keeping up with the group at a lower cadence? If so, they are in that higher gear ratio.

This sums up the problem very well. There is little finesse to the PAS if the system is based only on crank rotation, not torque. I find it nearly impossible to smoothly "idle along" below 10 - 12 mph when caught in traffic. It can be done roughly by quickly tapping a brake to cut the power and limit the surge, but it is still a nuisance. In those situations I usually turn off the power and ride it like a normal bike - far easier than fighting the PAS. I also cut the power when riding through crowded areas (parks, swimming beaches, etc.) so that I am not fighting the PAS while in tighter conditions.

Another alternative in those situations would be to stop pedaling and gently use the throttle to maintain an even speed. But there tends to be a short delay between throttle cutoff and actual power cutoff, which can be touchy in traffic.

I lurch. Don’t take it personally just don’t ride in a group with ebikes. If you were part of a racing club that trained regularly and had weekend warriors join training rides you’d have other another set of problems with half wheelers.

FYI: https://www.bikeforums.net/electric-bikes/

I'd not be so quick to blame the riders. The e-bikes sold in the U.S. are quite overpowered. Layer on a bad PAS and you've a problem. An average rider uses 200w to go 20 mph on flat windless ground. A bit more if they're overweight or going uphill or in to the wind or faster. A bit less otherwise. A 120w e-bike will provide about 50% of that (there's about 15% loss due to transmission and extra weight) so you can ride 20 mph for the effort you'd normally expend for 14 mph. That's a pretty big boost. Even going up a hill that extra 100w makes a very major difference.

500w or 750w is more than many people can produce for more than a few seconds so even with a good PAS these are usually producing very significant amounts of power - more like a multiplying factor than an assist factor.

The best e-bike I've ever ridden was 160w. It provided plenty of assist but was also quite smooth. The 240w version with the exact same PAS was noticeably jerkier. The PAS had two variables IIRC; assist level in % of watts produced by the rider and a taper curve. The lower the assist level the smoother the 240w version was. The 160w was somewhat similar though even at 100% assist (1w assist for each rider produced 1w) it was still smoother than the lowest setting of 20% for the 240w version. The taper curve made little difference in jerkiness.

Electric commuter trains have the same problem with jerky power delivery. Nature of the beast.
-E-bikes have no clutch that can smoothly initiate movement. Adding such a clutch to an e-bike or e-bike kit would jack up the price a bit.