What do you suggest for the best feeling pedal assist?

I'm thinking of switching over my project from a heavy commuter to more of a light, quick bicycle that uses pedal assist to turn it into a little rocket.

Is there a component recipe that creates a very natural feeling pedal assist. I've heard that some units have very good pedal assist (mostly responsive and scale well to your inputs) and others are very poor (boolean, only know when you're pedalling and when youre not)

Any thoughts on this?

Luke

I'm interested to see responses to this too. I'm starting a similar build using a bafang hub motor. I have an older ecrazyman controller that has pedal assist but I'm wondering the same things. I would be nice to have torque sensing. Do any low cost escs have that? I'm so used to using RC escs that I'm a bit out of the loop as far as bike stuff goes.

The most natural feeling pedal assist is Bionix. Expansive, low power and designed with proprietary components, but the best pedelec kit that one could buy.

The BionX is the only ebike I've ever rode, the pedal assist felt incredible. I've come to understand from you and others that the alternatives pale in comparison. My last bit of research was almost five years ago, so I hoped that this had changed since then.

My inclination is to put strain gauges in each crank... but getting the signal from the spinning cranks to a controller is a whole nother story.

I think what you're looking for is a suitable torque sensing bottom bracket (like a thun) and a CA companion.

A magnetic pas sensor only detects rotational movement around the magnet ring. So movement translates into in/off throttle response at a specified setting. There is a delay in motor start and stop with this technique and it only applies your preprogrammed throttle amount.

With a torque sensing BB, it's more like a twist throttle than on/off. Higher torque translates into higher throttle and has less (probably none with a good setup) delay.

As was mentioned, bionx and Bosch both use the torque sensing technique.

The CA V3 can operate with a torque sensing BB (torque and RPM scaling) or with a simple PAS wheel (on/off or RPM scaling). It's an easy retrofit to any hub motor system that can yield very acceptable results. I use the PAS wheel with RPM scaling on a heavy cargo bike and like it a lot.

That said, what makes PAS work is the software and the firms making units with matched bikes/motors/sensors/algorithms as the entire purpose of the product are way ahead of the V3 that must cater to a mix of all manner of vehicle weights, motors, controllers, and PAS sensors. These are different worlds from the perspective of control problems and sophistication.

So - to get the most integrated feel, buy a whole bike. To retrofit and get a bike-like riding experience, get a Bafang mid-drive with matched motor/sensor/controller/algorithm. To use a hub motor, the CA V3 with torque-sensing BB is a good possibility. I'm sure others can step up in this last group with recommendations for controllers with built-in PAS as an alternative.

I've only got experience with a THUN torque sensor/CA3 but for what it's worth I cannot imagine that a bionx has anything on it... With a caveat. You have to be willing to play with the settings (there are many) to get the response you want.

I'm using the system in a handcycle where I tend to have much lower pedal rpm, need more assist than a typical rider (just try pedaling with your arms some time), and producing the kind of torque most bicycle cranks see is extremely hard on the joints. With the help available on this forum and some time tweaking settings I now have a system the responds very naturally and exactly how I want. I had to play with parameters that I'd never have had access to with a bionx or other "package" set up.

As far as compensation for different vehicle weights etc. every system on the market has to deal with different size/weight bikes, different wheels sizes, different tire hardnesses... All kinds of circumstances. The CA3 is the only one that allows you to tweak parameters to make everything work together.

If you're the DIY type, and don't mind investing the time learning the ins and outs of the CA3 I don't think there's a system on the market that will allow you to customize how your bike behaves even close to as much as the CA3.

And all those benefits don't even take into consideration the best part... Every component in a CA3 based bike is nonproprietary... Use whatever batteries, motors, controllers, PAS/Torque sensors you like and swap them at will.

Check out the unofficial set-up guide, and the info on GRIN's website. If you're not intimidated by what you learn, I don't think you can beat the CA3/THUN.

http://endless-sphere.com/forums/viewtopic.php?f=4&t=37964&start=225#p571345

http://www.ebikes.ca/product-info/grin-products/cycle-analyst-3.html

If you get a controller with LCD and 5 levels of PAS, you'll be happy. You don't need to the complexity of torque sensors and Cycle Analysts.

The older style controllers often have no LCD and no adjustment on PAS. Instead they have ridiculous power algorithms that make the bike unrideable. A lot of people here on ES still use this type of controller for some reason.

With the S12S and S12SH sine-wave controllers, you can even switch them over to current control for a more natural feeling.

MadRhino said:

The most natural feeling pedal assist is Bionix. Expansive, low power and designed with proprietary components, but the best pedelec kit that one could buy.

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Ich wouldn't call a 46V (13s) system with a 30A controller "low power". That's around 1300W el. input. I'm not sure if huge motor power can be seen as an advantage in a a pedal assist bike.

The good thing about BionX is that you can configure it to your lining with the various codes (official and inofficial ones) and hacked software.

You can also run it on throttle or on both.

There are lots of other good pedal assist systems from Bosch, Panasonic. Impulse, Alber (Xion), Ortlinghaus (Greenmover, go-swiss-drive), Falco, etc...

None is as configurable as a (hacked) BionX systems

Some things to know about the BionX sensor at the rear axle:

If you put oil there chance is high that the sensor will become loose and if you are not able to replace it (you need to open the motor) you can throw it away (or run it at throttle only).

The amount of "torque" mesured depends on the tooth of your chain ring. In lower gears you get more assietncae for the same effort. That's how it works, you can not change that.

BionX motors can be bought quite cheap over here at ebay.

Wheels_78 said:

I've only got experience with a THUN torque sensor/CA3 but for what it's worth I cannot imagine that a bionx has anything on it...

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The Thun sensor is designed in a way that it can only messure the power from one foot/crank, the other one has to be extrapolated via software. That may work well (or not).

I personally don't like pedal assist. Sometimes it kicks in unexpectedly which is not safe in my opinion. I like thumb throttle and to have power on demand the best.

Actually, in my perspective and experience a Bosch system has the best feeling, bionx works great too it is true, but it is still an Hub and not small too....and Seems that the OP was looking for a "light, quick bicycle that uses pedal assist to turn it into a little rocket" Maybe it is my bias, but that doesn't match with a Bionx system in my mind, I have seen some road bikes with bionx but the almost 6 kg of the motor on the wheel (an old PL250 on my scale) and the big diameter still make me think that isn't the best option for such a cycle....
I think that for a true lightweight e-bike (say under 14-15 Kg) a small geared hubmotor (2-3kg max) is the best way to go...the problem is that a motor with windings for the right wheel size is too slow for these bikes, however a faster motor (lower turn count or overvolted) isn't easily reliable due to the gears and the small motor size...at least if you need the bike to be used as a normal fast bike can (2 digit climbs - flats - fast downhills)
Given that, from my perspective, the CA3 + thun or simply the Variable PAS that actual controller/display combos are able to provide are the best way for your question. Unless you would like to spend x000$ for a complete bosch bike or $1000-2000 for a new Bionx kit

Cephalotus said:

Ich wouldn't call a 46V (13s) system with a 30A controller "low power". That's around 1300W el. input...

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That is about dimensional relativity. I am used to pull 150A off a 24s Lipo pack, so 1300W is looking like very low power to me

I agree with D8veh 100%.
I'm in the process of converting my Q100 "Cute" powered Ebike over to sine-wave controllers.
So far, I have done just the front wheel using the tiny SO6S controller w\ the SLCD-3 display and it works almost seamless.
Select the level of assist and hold the throttle WOT for 10 seconds or so and the cruise activates. Since it's a low power system, there is no lurching or such, just smooth assist.
The display offers two types of assist, current limiting and speed limiting. I think I'm using current limiting(or what they call "imitation torque control", still learning the system).
Level one is good for about 14 mph(200 watts) and the levels step up to about 22 mph(500 to 600 watts). I use the first three the most.
I say it's almost seamless because one has to dis-engage the cruise to change assist levels.
The small button module mounts next to the throttle and is right at your thumb.
I installed the PAS, but the cruise and adjustable assist works so well, that I don't think I need it.
If one is serious about pedaling, I think it would be hard to beat the Q100\SO6S\SLCD-3 combo. for the money.
If I was going to use a single motor, I would go with the Q100H (260 rpm @ 36V) on the front for an easy to install, low cost and smooth working pedal assist.
But be forwarned, the SO6S will not live on 48Volts, maybe around 44 V is max.

BIONX is the most smooth /jerk free/ pedal assist I tried.
Incredibly configurable for user /mostly through dealership which only has computer interface/.
No tricky /endless adjustments/ , dirt-prone PAS sensors to install o BIONX - sensor is inside motor.
Nothing "kicks in unexpectedly" on BIONX.
Designed and manufactured in Quebec, Canada.
Of course PANASONIC drive is a legend used by many ebike manufacturers.

Well, the price of the Bionx kit causes me to have an involuntary knee jerk.
Could build 7 Chinese kits for the price of one Bionx.

d8veh said:

If you get a controller with LCD and 5 levels of PAS, you'll be happy. You don't need the complexity of torque sensors and Cycle Analysts.

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Until you try a bike with a torque-based pedal assist. Quite the authoritative tone you take. You seem to try very hard to convince yourself, and unfortunately others, of this.

lester12483 said:

I personally don't like pedal assist. Sometimes it kicks in unexpectedly which is not safe in my opinion. I like thumb throttle and to have power on demand the best.

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I've never experienced this on either of my BionX bikes, or heard of it on any other BionX bike. BionX also have a thumb throttle. Why did you feel the need to make this comment in a thread titled "What do you suggest for the best pedal assist?" I don't believe I need to check your website to see if the bikes you sell have pedal assist.

motomech said:

Well, the price of the Bionx kit causes me to have an involuntary knee jerk.
Could build 7 Chinese kits for the price of one Bionx.

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The disinformation brigade is really laying it on thick here...
I posted a link last week to a site where a new 36 volt BionX system could be bought for US$1199. I don't think you can buy an entire new kit with battery, motor, throttle and controller of remotely similar quality of construction and ride for much less than that.

silentflight said:

d8veh said:

If you get a controller with LCD and 5 levels of PAS, you'll be happy. You don't need the complexity of torque sensors and Cycle Analysts.

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Until you try a bike with a torque-based pedal assist. Quite the authoritative tone you take. You seem to try very hard to convince yourself, and unfortunately others, of this.

The disinformation brigade is really laying it on thick here...
I posted a link last week to a site where a new 36 volt BionX system could be bought for US$1199. I don't think you can buy an entire new kit with battery, motor, throttle and controller of remotely similar quality of construction and ride for much less than that.

Click to expand...

I've tried just about every type of torque sensor system on the market: Bosch, Bosch Active, 26v Panasonic, 36V Panasonic, Panasonic hub motor, Bionx old and new, Kakhoff Xion, Kalkhoff Impulse, Falco, Xofo, Smart, BH Emotion, Cycle Analyst with Thun, plus loads of others that I can't think of at the moment.

I'm a development engineer for a well know UK ebike brand, so I try to investigate everything that's new on the market.

I've spend probably over $25,000 looking for my own ebike nirvana. I haven't found it yet.

I wouldn't have any of the above-mentioned systems on my own bikes. Nearly all of them make pedalling harder work and preclude the use of a throttle. I prefer the normal 5 levels of PAS with Speed control and a throttle to use when I need it.

Everybody's entitled to their own opinion. Please don't try and imply that my opinion is without basis.

d8veh said:

I've tried just about every type of torque sensor system on the market: Bosch, Bosch Active, 26v Panasonic, 36V Panasonic, Panasonic hub motor, Bionx old and new, Kakhoff Xion, Kalkhoff Impulse, Falco, Xofo, Smart, BH Emotion, Cycle Analyst with Thun, plus loads of others that I can't think of at the moment.

I'm a development engineer for a well know UK ebike brand, so I try to investigate everything that's new on the market.

I've spend probably over $25,000 looking for my own ebike nirvana. I haven't found it yet.

I wouldn't have any of the above-mentioned systems on my own bikes. Nearly all of them make pedalling harder work and preclude the use of a throttle. I prefer the normal 5 levels of PAS with Speed control and a throttle to use when I need it.

Everybody's entitled to their own opinion. Please don't try and imply that my opinion is without basis.

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Good to know. I was wondering why I am so happy with my MAC10/S12S/PAS combination...

I have been commuting to work on bike for 20+ years, and for the last few years I've used a Bionx PL350 equipped bike part of the time. The experience/feel of the assist is generally good, depending on my own riding mode/behavior.

It feels most natural when I am standing on the pedals to ride up an incline, or when I'm tired and getting sloppy in my pedal stroke (mashing). When I spin in good form using hamstrings with fairly even/constant torque throughout the pedal stroke, the Bionx assist essentially drops out on me. It seems its torque sensor relies upon impulses above an assumed zero baseline, and when I spin with relatively constant torque it starts treating that as the baseline. I verified this behavior by entering diag mode #3772 and observing its (filtered) torque input digits and assist output levels. From a design perspective I can understand why you would continuously auto-compensate for drift in the torque sensor, but I think this isn't optimal for experienced riders. Lately I find myself using the thumb-throttle during "cruise" so that I can spin with "good form" to layer a relatively constant leg power on top of the Bionx output. I've been wondering if there are solutions that work better in this regard, but I get the sense from d8veh's experience/investigations that there isn't...

After four years on various electric bike forums, I postulate a theory: If you like dressing up in lycra, you will probably prefer a torque multiplication system with a torque sensor. If you prefer to cycle in normal clothes, you'll probably prefer a pedal speed sensor with a decent multi-level PAS system.

Some systems use the torque sensor only to determine that you're pedalling, but the controller still works on speed control. Some systems combine torque speed and cadence sensors in an attempt to give ideal power. IMHO they all have advantages and disadvantages.

The only PAS systems I'd definitely avoid are single level ones with a cadence sensor, higher powered ones with a three-speed switch, and the most diabolical of all: those that give more power the faster you pedal.

I'm in the normal clothing category.

But I am interested in adding a torque sensor for one purpose: to make takeoffs more natural. With the S12S and PAS sensor, it takes about 120 degrees of rotation for the assistance to kick in. With a 60 lb bike, this can make for occasionally awkward uphill starts. I'd love for the bike to sense the pedal pressure, and respond.

Since i don't have a CA, and use a Patterson Transmission, a BB torque sensor isn't an option. But I'd really like to get my hands on one of those BEAMts sensors. They feed directly into the throttle input, so can be used with any controller. With the S12S, the torque torque sensor could be used to complement the PAS sensor.

I'm in the normal clothes group too. My eZip Trailz had was equipped with PAS before I bought the 36V controller for it, it worked okay but on a 24V system it only gives yor 50% of the power. You then can throttle to get full power; I found myself using the throttle quite frequently. I am really happy with my 5 level PAS and digital display system that came with the yescomusa kit! At first I wasn't going to bother installing the PAS, but I am glad I did! I only have experience with these two PAS systems, hopefully I will get the chance to experience the Bosch or Bionx systems in the future!

I think that I am a frustrated and confused cross dresser then -- I commute in loose MTB shorts (pockets), and wear a lycra jersey . The notion of an auto-sensing proportional input system that doesn't require much fiddling appeals to me.
My intuition has been that PAS-only system at a high setting would have response lag with exaggerated assist at low speed. Perhaps I just need to try out a good PAS system or a hybrid PAS/torque system to compare...

Avitt said:

I'm in the normal clothing category.

But I am interested in adding a torque sensor for one purpose: to make takeoffs more natural. With the S12S and PAS sensor, it takes about 120 degrees of rotation for the assistance to kick in. With a 60 lb bike, this can make for occasionally awkward uphill starts. I'd love for the bike to sense the pedal pressure, and respond.

Since i don't have a CA, and use a Patterson Transmission, a BB torque sensor isn't an option. But I'd really like to get my hands on one of those BEAMts sensors. They feed directly into the throttle input, so can be used with any controller. With the S12S, the torque torque sensor could be used to complement the PAS sensor.

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Can't you use a throttle for take-off?