What is a normal ebike riding experience?

[Roseville]

I purchased a DiamondBack Trace EXC from REI, and I'm trying to understand if I have a problem, or, if the tech rep from Curry is right.

Issue: while riding at 20.1mph in first level assist, the bike begins to pull back, like the assist level was disengaged. When I dropped to 20mph, or below, this pulling sensation went away.

While riding at 4th level assist over 20mph, the pulling sensation sometimes comes back, then goes away, again and again.

REI tech support was unable to supply any information beyond referring me to the manuals, which I had alread read, while the Curry staffer said this was a normal experience.

I generally have ridden only on flat streets in the highest chain gear (not the gear for hill climbing)

Your insight is appreciated.

Thank you

 

[flymeaway]

Your insight is appreciated.

Not sure what you mean by "pull back", but the bike is probably limited to 20mph motor assist. Above 20 and the motor shuts off.

Court J.

 

[Roseville]

Assist is not limited to 20mph. I've gone as fast as 28 mph.

The 'pulling' back effect may be the motor disengaging for a bit, then, engaging again

 

[Marceltt]

Assist is not limited to 20mph. I've gone as fast as 28 mph.

The 'pulling' back effect may be the motor disengaging for a bit, then, engaging again

I would have to agree with Court J on his reply. Cut off is at 20 mph for most e bikes. There may be just a few that have cutoff from motor at 28 mph but not many at all. The pulling back you feel is just the motor being cut of at a limit top speed.

 

[MLB]

If it's a speed pedalec (28mph) then it sounds like there's a problem. I've felt that a few times in few situations, maybe most when I was peddling hard and then stop, and then back on again. Seems like some controls contradicting each other and telling it on-off a few times. If it's just a little under weird situations I wouldn't worry about it. If it's all the time doing that I'd get it looked at while under warranty.
The next time it does that, try shifting gears up or down 1 and see if that changes the response from the bike. Seems a bit as though Ebikes can have their own slight "flat spots" of reduced response (tuning choices) just like an internal combustion engine.

 

[Cornishman]

I might have experienced a similar situation. My European spec bike gives assistance up to just over 25km/h. There are times, on the flat, at about 24km/h when pedalling seems strangely difficult and it becomes easier once the assistance cuts out as the maximum speed is reached. I'd presumed that it was a point where the small amount of electrical assistance from the motor is less than the drag on the system. If, at these speeds I feel that the motor is hindering not helping I switch the assistance off.

 

[Cameron Newland]

It sounds like you either have a torque sensor malfunction or you're simply not putting enough torque down on the pedals to activate the assist.

My girlfriend has a torque-sensing pedal assist ebike and when I ride it (I'm 180lbs), the motor offers strong power all the time, however, when she rides it, the finds that the power delivery is sometimes more intermittent, and I believe it's due to the fact that this ebike's torque sensor is feeling more weight and more pedal torque when I ride it, and it's giving me the assist I want when I expect it, however, because she weighs less and because she has a different riding style (more seated, no standing on the pedals), she isn't always able to get the assist she desires. Perhaps you're experiencing an issue similar to what my girlfriend experiences, or perhaps you need to have your torque sensor replaced.

I have an IZIP E3 Dash which is identical in many ways to your Diamondback (same battery, display, etc), and I've found that in the first pedal assist mode, I get a little bit of assist beyond 20MPH, but not much. It's better to be in three or four to get more assist above 20MPH.

 

[EasyMotion Rider]

A safe assumption would be that ebikes all have weird and differing computer/motor/module problems. my eflow will drop the power assist if do not pedal continuously and not resume sometimes unless i come to a near complete stop, but not always. i dont worry about it, i just always pedal even if i am going 30 mph down hill!

 

[MLB]

Quite a few bikes have adjustable control settings where you can change when the assist kicks in, how hard, etc
On my Falco at least the torque sensor settings can be changed.
As Cameron pointed out, if you are running out of gas (how much input you are adding) then the assist will peter out also. If you're straddling the "on/off" point of the motor kicking in, those symptoms can occur.
Might be some worthwhile time spent there if it is configurable.

 

[Roseville]

If it's a speed pedalec (28mph) then it sounds like there's a problem. I've felt that a few times in few situations, maybe most when I was peddling hard and then stop, and then back on again. Seems like some controls contradicting each other and telling it on-off a few times. If it's just a little under weird situations I wouldn't worry about it. If it's all the time doing that I'd get it looked at while under warranty.
The next time it does that, try shifting gears up or down 1 and see if that changes the response from the bike. Seems a bit as though Ebikes can have their own slight "flat spots" of reduced response (tuning choices) just like an internal combustion engine.

Thanks MLB. It is a pedalec. I've been up to 30mph, according to the display, on the flats. I plan to add a cadence bike computer, then do some formal tests, and share them with Currie.

 

[Ravi Kempaiah]

highest chain gear

This is the crucial point.
Being in the highest gear makes the sensor to think your cadence is low but if your cadence is high in the highest gear, the system should put out more torque.
Most of the "pulsing" issue in torque sensing bikes comes from uneven cadence at high speeds.

 

[Roseville]

Ravi, I think you hit the nail on the head - uneven cadence.

On my next ride, probably in the morning, I will pay attention to my cadence.

Thanks for your input, Ravi.

 

[Ann M.]

The 2015 Diamondback Trace EXC has a combination of torque and cadence sensors connected to the bottom bracket which should give a more responsive feel to the pedal assist. Not just having to stomp the pedals to get power like a pure torque sensor and not so automatic as with a solely cadence sensor. Using too large of a gear with too few pedal strokes (like Ravi pointed out) will potentially cause a jerky feeling particularly as you get close to the top speed limit where the motor will cut out normally. Use those gears a bit more and I bet you'll not have such a problem.

 

[CJDub]

I also bought this bike from REI. Am looking for a new battery and getting very frustrated. REI can't help me. I have opened a support ticket with Diamondback, but they are not responding. I am considering having the battery rebuilt by Ebike Market Place in Las Vegas. Anyone else running into this situation?