Pedal Assist question - Retrospec Chatham ebike

Signmom99

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I'm brand new to e-bikes and something just doesn't seem quite right. I just purchased a Retrospec Chatham e bike. It has 3 levels of pedal assist along with a thumb throttle and also 7 gears. It appears that the only difference in the pedal assist between Low-Med-High is that it increases my speed. I want to use my legs more and not have the "assist" help so much. But even in low (no matter what gear I'm in), it takes me up to full speed and my pedaling is basically free wheeling, there is no resistance. Is this normal or might something be wrong with my set up? Perhaps that is how the less expensive e-bikes are? I hope this makes sense. This is riding in town on flat elevation. Thank you for any input.
 
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Should be just a speed of crank rotation sensor, though possibly a torque sensor, which often have setup issues.

Try testing on Low setting, with a very low gear setting which would allow very fast crank rotation with little torque. Try very slow rotations, with no pressure or torque, for a minute or so, and also very fast rotations, both freewheeling. also stop pedaling altogether. IF there is no speed change, with the different pedaling speeds, then EITHER you have a torque sensor and not a rotational sensor, or the rotational sensor is setup wrong or malfunctioning.

Torque sensors are great when they work, not so much when they don't, and fairly pricey to replace. Also they require a power supply.
they often have calibration and/or installation or power issues, sometimes compatibility issues with particular controllers.

Rotational sensors are cheap, simple to install. minimal calibration, and require no power source.

An alternative method is to simply set the throttle to a comfortable speed, then select gearing to comfortably pedal as you wish with that speed. Simple, minimizes problems.
 

Signmom99

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Thank you for responding. I'm not very mechanically inclined but am married to a mechanic who's hobby is motorized bikes (gas). That said, when I am in first gear and on lowest pedal assist - after one rotation of the pedals it takes off and goes up to about 11-12 mph. The speed stays the same if I pedal very slowly or if I pedal very fast. However, if I stop pedaling the bike starts to slow down much the same as taking ones foot off the gas pedal in a car.

I'm guessing that this bike is probably equipped with a rotational sensor since it is toward the lower price point.

I will be biking with my granddaughter this spring/summer and being 10 she will be riding my Trek so going slower will be important to me but I would still like a little assist, hence wanting to be able to adjust how much assist I receive.

Thank you for the input. This gives me a place to start.
 

HumanPerson

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Hello Signmom99 :)

I cant seem to find the display that your ebike uses, would you mind telling us the make and model of your display please.

That way we might be able to get you some information on the settings if we can.

Ride Safe mom! :cool:

HP
 
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Disconnect the thumb throttle cable and test. One thing which could cause your symptoms is IF your thumb throttle is floored, but the PAS or pedal sensor is primary. Which it usually is. This would give you essentially an on/off switch activated by pedal usage, which is what you seem to have.

Power off when disconnecting or re-connecting any and all cables.
 

HumanPerson

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This make/model of ebike does not come with a display sadly. I wish it did.
Interesting. Is there anyway you'll be able to get a different ebike that has a display which lets you adjust setting parameters?
Can you link me to the ebike you have?
 

CuckooForCargoBikes

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Looks like it's this model:

The initial jolt is a common aspect of many cadence based sensors as it just goes by movement of the pedals/cranks rather than the pressure of the pedaling. Unfortunately, without a display and the ability to modify the settings, you may be stuck with how your ebike handles; many cadence sensors can be modified by the user by going into the advanced settings and changing the power input to the different levels. Ebikes that use torque sensors tend to be much smoother when delivering assist because they go off of pressure input from the rider rather than just the spinning of the cranks, so it feels more natural rather than abrupt.
 

Signmom99

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CuckooForCargoBikes, that in fact is the correct bike. I have determined that although not the cheapest out there, it is definitely an entry level bike. I am in my early 60's but still have some adventure left in me and I think I'll outgrow this bike by.....oh prob next week, lol.

I do not have any opportunity to "exchange" this bike for a different one so will chalk it up to lesson learned. Plus being in a small town, there are not a lot of choices. So, I'll bide my time and keep researching for a bike that has everything I want and also won't totally break the bank.
 
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From the picture, disconnecting the throttle altogether may be a bit difficult. As an alternative, move and hold it to the far end of its travel, test as described while it is held at both ends of its travel. The on-off behaviour described IS how many similar controllers work, BUT this is usually only when throttle is at maximum. On some, ANY throttle at all is seen as maximum and throttle must be all the way off for PAS to work normally.

The good news is that you could replace the controller and display with minimal expense, however all that nicely-bundled wiring will be a royal
PITA to deal with. New controller would give you improved control over PAS settings.

My own display is an older model of yours, but identical buttons and LEDs. No programmability whatsoever, but I don't use PAS, just throttle and have no issues. I put the throttle where I want it and pedal accordingly, when I want to. Specifically, the three speed settings are NOT pedal sensor controls at all, but limitations on maximum speed. In fact, my kit did not come with pedal sensors of any kind..

What you are getting may be the way it is SUPPOSED to work, this may be a Kluge to deal with local regulations. I assume you are in England or Europe?

One thing with the throttle test, see if it has any range other than on or off. Most are only "live" for less than half of the total travel, so checking for a range of speed settings involves some small movements.

it may be that the throttle itself is your PAS controller for differing levels of assist.
 

Signmom99

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Nelson37, I'm in the US. Throttle is pretty much all or nothing, the feathering option isn't very good. I've pretty much decided I'm not going to tinker with this bike, just enjoy for the time being until I can get one I really like and want. Do I "need" all the bells and whistles that I'm wanting? No probably not, at least not at my age, but we still like options and choices no matter what our age.

Thanks to everyone who has helped on this thread............
 

MikeR.

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If you have not already given up on this. You bike is like most pedal assist bikes. Some have 3, 5 or up to 9 levels. The level is not a power level, it is basically a speed sensor/setting. Level one might take the bike to say 8 to 11 mph. Above that speed, the assist cuts out and you are on your own. What gear you are in has no effect, other than your pedal speed, the motor works directly on the rear wheel. Level one = 11mph, level 2 = 15 mph, 3= 19mph, as an example. You might be able to contact the seller / manufacture and find out if there is a way to change the settings, Thats a "good luck" sort of thing.
I found the HeyBike Cityscape to be a good low cost example (currently $899 with free shipping, and sometimes free accessories , check it out on YouTube, or HeyBike.com and (you can adjust the settings)
 

Signmom99

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Mike you are 100% correct on your assessment of this particular bike. There is no way to change settings unfortunately. I have spoke to the mfr already. That said, there are so many aspects of this bike that just don't "float my boat" that I am biding my time, saving my pennies, and looking for a bike that will meet all my wants. I have lots of time. I'm figuring it will be next spring probably before I can get a new one.

Maybe I'll coerce my husband to let me ride his WickedThumb ebike when it gets here!!
 

Wingsy

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I'm brand new to e-bikes and something just doesn't seem quite right. I just purchased a Retrospec Chatham e bike. It has 3 levels of pedal assist along with a thumb throttle and also 7 gears. It appears that the only difference in the pedal assist between Low-Med-High is that it increases my speed. I want to use my legs more and not have the "assist" help so much. But even in low (no matter what gear I'm in), it takes me up to full speed and my pedaling is basically free wheeling, there is no resistance. Is this normal or might something be wrong with my set up? Perhaps that is how the less expensive e-bikes are? I hope this makes sense. This is riding in town on flat elevation. Thank you for any input.
I discovered the same thing with my Lectric XP2 step-thru, which I just got yesterday. It seems that at a PAS value of 1 the motor will be supplied enough power to take you to about 6mph (level ground) once it detects that you are peddling, and about 10mph with a PAS of 2, and increasing up to around 20mph at a PAS of 5. The thing is it doesn't matter how fast you peddle - the power to the motor will remain the same with a constant PAS. But if you peddle faster or move to a higher gear you'll reach a point where you can propel the bike faster than the current motor power will deliver, and that's when you start to get a workout. And it is also where the motor is truly supplying an "assist". It's almost like "peddle assist" should actually be called "motor trigger" since peddling is what turns the motor on (and the PAS setting says how much power is supplied to the motor when it is on). I thought it was a lot more sophisticated than it is. I was expecting it to drive the motor with a proportional amount of power based on how much torque your legs are supplying the sprocket.
 

Signmom99

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Exactly!! I could not convey it correctly, so thank you for that. With mine, in the lowest level of PAS I automatically am thrust up to about 11mph. When riding in town, that is too fast because I'll come to an intersection and have to brake before my legs can get any workout. So, what I've been doing is to pedal out with no electrics turned on, then using the electrics coming back. For now that will have to suffice until I can get the bike I really want. And that a brings me to another dilemma! Which one......I think I have it narrowed down to 3 and think I've eliminated one of those. So, I have time. Figure it will be next spring before I can afford to get the one I want and will just ride and enjoy this one for now. If nothing else I still have my regular Trek bike I can use for a work out.
 
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