Crankwinder

I don't though, pick just one thing. I also mentioned the facility to ride socially with muscle bikers. They are demoralised by e-bikers zooming up the hills, which unfortunately is the only way to keep a hub-motor spinning at something like its most efficient rpm! But before I get onto hub motors, what of those supposed crank drive problems? Sure, cadence can vary, but any cyclist with some experience of riding on muscle power alone, plus an ounce of intelligence, knows very well how to keep their cadence reasonably constant. It's simply a matter of equipping one's bike with a sufficiently wide range of gears - especially low gears - and shifting as appropriate. With today's highly reliable, wide-range '1×' derailleur systems, it's easy to keep a crank-drive spinning nicely and is second nature to anyone who already has a few decades of muscle-biking experience. I'm so accustomed to pedalling at 80-90rpm that it just feels wrong to let my legs drift round at 60! Gears too low, is that even possible? Given that you can't fit a chainwheel much smaller than 40T on most crank-drives and the ubiquity of 11T top sprockets, it would be a very strange e-bike that lacked a high enough gear to work efficiently at 25kmph. As for those poor souls who never learned and cannot now be bothered to move their legs more than once per second, I guess that for them, a hub motor may be the best thing. But what size of hub motor? You write of your 48v 22A AKM128, that "it has all the power you need and it can give very good efficiency". I'm sure it does and can: that's a whole kilowatt! What you have there is an electric moped - not anything like a bicycle as we know it. Because that's how electric motorbikes and cars work: just bung a big enough electric motor in it and there is no need for gears. Your typical driver, after all, expects to go near enough the same speed uphill as on the flat. Bicyclists however, don't. A human pedalling a bicycle is by its very nature, a seriously under-powered vehicle for its weight. And the only way such a vehicle gets up a steep hill is slowly, in a low gear. E-bikes are supposed to perform much the same as a typical bicycle. (And that's yer typical bike in the street, NOT in the Tour de France!) That's why their motors aren't supposed to be capable of delivering more than 250W continuously. And provided it's delivered to crank, so one has the option of taking longer to climb a hill, 250W should be enough. Because energy = power × time, so take your time and a limited amount of power will nevertheless suffice. To sum up, if you want an e-bike that's something like a pure pedal cycle, but easier, choose crank-drive. And if you want something more like a motorbike, but would trade some speed for the freedoms of cycling, get a hub-drive. But unless you can avoid really steep hills, it'll have to be an illegal hub-drive!

That's true for the highest assistance level, for which the as-supplied cadence limit is 100% of the rated (i.e. peak efficiency) output revs of motor+gearbox, which as I said, appears to be 85rpm. I didn't want to make my post even longer but of course you are right, electric motors - just like our legs - are capable of turning faster than the cadence at which they work most efficiently, but only up to the speed where all of the supplied energy goes into making them go round and there's none left over to do any useful work. Cyclists call this "spinning out" and I think the same phrase also does very well for motors that have reached the condition of back emf = battery voltage. As far as I can tell (from spinning the pedals of my bike on a workstand and watching the controller's speed and power displays in the highest assistance level and a low enough gear to ensure this happens well below 25kmph) the BBS01B 'spins out' at a little over 100rpm. In all the other, lower assistance levels however, the factory settings of the controller software imposes articifially lower cadence limits. The result of these percentage "speed" settings is that the smaller amount of power provided at that level begins to fade at the relevant percentage of 85rpm and ends completely (i.e. the motor spins out) when you're pedalling at a cadence approximately corresponding with that percentage number (since the motor's 100% spin-out speed is approx 100rpm). By changing all of those "speed" settings to 100%, I've removed those artificial restrictions so that however much, or little assistance is requested, it does not begin to fade with increasing cadence until the motor begins to approach its natural spin-out speed. P.S. It is easy to be confused by Bafang's sloppy terminology, using 'speed' not only for the miles and kilomtres per hour travelled by the bicycle, but also for the revolutions per minute of its crank axle!

If you're frustrated by insufficient power from your Bafang BBS01B, it might simply be that you like to move your legs a bit more briskly than Bafang expects. Being a cadence (rather than torque) sensing unit, the Bafang cuts the current when it senses that you're pedalling quickly enough that you probably don't need any help. That's all very well, but as supplied only the highest assistance level delivers its full quota of current at the unit's rated revs per minute, which appears to be 85rpm. The lower levels not only have lower current settings, to deliver less power, but also begin to cut that power at lower cadences. And not just a bit lower. The lowest level (if you implement all nine levels) has a cadence limit of 32%, which means assistance starts to tail off at an awfully slow 27rpm! The result of these default settings is that anyone who likes to pedal quickly, doesn't get any help at all unless they select a much higher level of assistance than they necessarily want! Either that or pedal like a complete cycling novice! The best solution for someone who likes to pedal at 80 to 90rpm will be to set what Bafang calls the "Speed limit in Gear" of each and every assistance level (Bafang calls them "Boost Gears") up to 100%. And while you're at it I'd recommend reducing the "Max Output Power" percentages of the lower levels. The defaults, which start at 36% for level 1 of 9 (39% for 1 of 5) are all too high, so I find, for riding socially with muscle bikers of average ability. I set mine with five levels (i.e. levels 2, 4, 6, 8 & 9 of 9) at 9%, 21%, 39%, 60% & 100%. Those look like odd percentages but there's a sound technical reason why they feel right for me. If you're interested read this: https://www.pedelecs.co.uk/forum/threads/new-bafang-kit-has-different-non-round-plugs.49243/post-757361 There is a quick and dirty way of overcoming Bafang's too-low cadence limits and that's to set 'Keep Current' to 100%. This totally disables the tapering off feature: the controller keeps on passing the selected level of current to the motor regardless of how quickly it's turning already. The cadence limits simply become irrelevant. This option is not available however, in the new "CAN protocol" Bafang units that seem to be the only option from most suppliers.

Presumably that's the easily metered electrical input power, rather than mechanical output, that the motor will have no way of measuring. The difference of course, goes into warming up the windings of the motor and can be very considerable. The motor may be able to stand the heat, but the wasted energy will nevertheless reduce how much range one can get from a given size of battery. That's the main reason I choose mid-drive: by keeping the motor spinning at it's most efficient rpm, even up the awfully steep hills we have here in the Peak District, I don't need such a big and heavy battery to go the distance without range anxiety. And since I ride with a mixed group of e-bikers and muscle bikers, it's more sociable to go slowly up hills, which I can do by selecting a lower gear rather than a higher level of assistance.

I daresay we'd all get on 'like a house on fire'...

I've just dug found the 'Hackers Guide' I printed out for the old Bafang programming lead. This explains that 'Keep Current' is a % of the assistance level current (itself a % of the system's limiting current), that the current will drop towards when cadence exceeds the 'Limit Spd' for that assistance level. Setting 'Keep Current' to 100% means that there will be NO drop in current when one's cadence exceeds the 'Limit Spd' ('Speed Limit in Gear' according to CANbus terminology) for the assistance level. Whatever that limit may be, the motor will keep right on assisting at the same level until it begins to spin out, which seems to happen from 80 to 90rpm at the chainwheel. I now realise that setting 'Keep Current' to 100% is just another (quick and easy) way of overcoming the too low cadence limits of the lower assistance levels, simply by making all such limits irrelevant! So don't worry that you won't be able to set a 100% 'Keep Current' on CANbus. Setting the 'Speed Limit in Gear' to 100% for each and every 'Gear' (= assistance level) has exactly the same effect.

If you pretend to Eon that your E-bike is an electric car you can get their Next-Drive tarrif that currently charges (sic) only 7p per kWh between midnight and 7am. They don't actually check that you have an electric car (so I just named the one I'll probably get when our ancient diesel Astra dies) or care if you don't have a charging point fitted to your house (except then you can't get their smart drive tarrif that takes advantage of even cheaper spot prices). Of course they charge a LOT more for any leccy you buy during the day, but provided you have a big enough household battery, charged up every night, you'll seldom have to pay more than 7p. Unfortunately that goes up to 8p this year and I think the time period gets a bit shorter, but still a good deal. Our E-bikes have 500Wh batteries, so even if charging were only 60% efficient that would still be less than 7p per full charge.

I'm afraid I've never understood what "keep current" actually does, so don't miss the lack of any facility to adjust it. Maybe it's a factor in the new display's "Speed-up Character", that I also don't care to increase much above minimum. For me, adjusting the "Speed Limit in Gear" to 100% for all 'Gears' (assistance levels) has the desired effect of maintaining a reasonably constant level of assistance regardless of cadence - up to about 80rpm at which the motor seems to begin to 'spin out'. All I want from e-assist is what it's supposed to do: enable me to ride like I did on a pure muscle bike when younger and fitter, but not like a TdF superstar or a moped. Slow uphill is perfect, I don't want to drop my muscle-biking companions anymore than I want to be dropped! And it doesn't take very much assistance just to keep up, provided the bike has a low enough bottom gear to keep the motor spinning efficiently at the hill-climbing speed of a slow to middling rider.

Good news! I've now converted my Spa Ti Tourer and found that the new CANbus display/control enables all the tweaking that I want to do, to be done via the 'Advanced Settings' menu on the display itself I chose the Varstrom EKD01 display because it's not too bulky and can easily be adapted to fit the slightly larger diameter of a dropped handlebar (by fitting a thinner rubber liner in the clamp, that I cut from an old inner tube). I can't guarantee that other displays have this facility but I don't see why they wouldn't, since most of them are bigger and more expensive than EKD01. To me it seems a distinct improvement that the new system doesn't require connection via a programming lead to a PC in order to customise how assistance is delivered within legal limits. Or even beyond those limits, since maximum assist speed is one of the parameters that can be and indeed HAS to be adjusted, since the unit defaults to 99kmph! Wheel size defaults to 26in and may also have to be adjusted. Both of these settings are found under the Information tab of the Settings top menu. In order to change them you need to enter the settings password '2020' (cannot be changed, unlike the main screen password '0000'). Another thing you might want to change is the number of assistance levels. I'm happy with the system default of five levels. Select 'Boost Gear' under the Display Setting tab if you'd prefer three or nine. Beware that the downloadable instructions loose something in translation from Chinese (assistance level for example, is called 'Gear') and don't exactly correspond with reality. The option to select a different 'Theme' for the Display - of which there are supposed to be four options - just isn't there on my unit. 'Advanced Settings' on the other hand, aren't mentioned in the instructions but ARE there on my unit: last item before 'Back' under the Information tab. And thank goodness for that! Select Advanced Settings (you'll need to enter '2020') and you get the following list: Speed up Character Max Output Power Speed limit in Gear Start up Angel Exit The first three items in that list let you tweak the performance arameters of each 'Gear' or assistance level. Select one of those parameters and you'll get a list of three, five or nine 'Gears', plus Exit. Select one of those Gears and the next thing you'll see is a slider that can be shifted to and fro with the + and - buttons. Here's what they do. Speed up Character seems to set how much extra power the motor will apply in a short burst, in attempting to boost cadence (pedal speed) up to whatever limit has been set below. This parameter is tweakable from 1s to 8s - presumably those are seconds. I don't want a sudden jerk whenever I shift actual gears, so I set most levels at 1s, with 2s & 3s for the top two levels. I don't know what 8s feels like but certainly don't need it and am pretty sure I wouldn't like it! Max Output Power is THE key setting parameter. The slider sets the percentage of maximum output power (legally 250W) that'll normally be applied at that level. Assuming 50W from me, I did the maths to work out what percentage of 250W assistance the motor should provide in order to get the same percentage increase in total power at each change of level from 50W at zero to 300W at level 5. Accordingly I set level 1 at 9%, 2 at 21%, 3 at 39%, 4 at 60%, 5 at 100%. Speed limit in Gear means pedalling speed, what cyclists usually call cadence. This slider sets the percentage of the motor unit's maximum cadence - which seems to be just over 80rpm - at which the unit decides you are pedalling fast enough already not to want any more help. Maybe it suits novice and occasional riders to pedal slowly when the going is easy and faster up hills, because that's how the default settings are, with lower cadence percentages at lower assistance levels. As a lifelong cyclist however, I'm accustomed to pedal at about 80rpm regardless, if anything slightly slower uphill than on the flat. So for the time being I've set all my sliders to 100%. I might put levels 4 and 5 a little lower, but since I haven't needed more than level 3 so far, even on 1:5 hills around here in the Peak District, I'm not in any hurry to do that. Start up Angel (sic) is the deity who decides how far you must turn the pedals before the motor kicks in. The default is 60° and as that's also the minimum end of the scale I haven't changed it, or bothered to discover how much further one can delay the arrival of heavenly assistance! Your mileage/maths may vary, but for me the above numbers are working very nicely. I call them my ten times years younger levels. Even a mere 23W of assistance seems to make hills as easy as they were ten years ago and with 250W it's like I'm 21 again!

A couple of years ago I converted my wife's bike with a Bafang kit. She likes to pedal with a high cadence but didn't get any help unless she pedalled slowly or selected a much higher level of assistance than she wanted. So I got a programming lead and tweaked the cadence settings of each power level. She's now a happy e-biker, especially since I also fitted the throttle so she can actually start on a hill! Now I want to convert my bike too, so I got another kit, but found that the display has a triangular connection. I've searched for but cannot find a round to triangular adapter. What I have found are arcane discussions where the terms UART and CANbus are bandied about, with some despairing that the latter system, which Bafang have changed over to, cannot be programmed at all! Others alledge that all the programming one might want to do can be done through bluetooth with an app. Is that right? Will I be able to adjust the cadence at which assistance is available? Because I'm not about to change the habit of a cycling lifetime and start pedalling like a slug!

Who are "They", the cat's parents? I guess you mean those enquirers like me who are merely "Finding their (electric) wheels". You may be an "Esteemed pedelecer", but I'm afraid your reply is no help at all. Are you not aware that 'start assist' is a thing - and can be found on an increasing number of European pedelec systems? Perhaps not, if your focus is on delivering more power and speed to those who don't really NEED it. I may not yet know all that much about pedelecs, but I know how to find things out and do seem to have discovered a solution that satisfies all of Eddy's requirements.

I've been crawling over Fazua's website and it looks like their latest 'Ride 60' system (but none hitherto) has what Eddy needs, namely a 'Boost' function (see p30 of this pdf manual) that provides up to 4 seconds of 450W power from standstill. That should be enough to start up any hill, while he gets into the saddle and transfers his good left leg from ground to pedal. Provided he's selected a suitable gear of course. But as this model also has 'Push Assist' (p31), gear selection can be sorted by walking a short distance in that mode whilst leaning on the bike and operating the shifters. So: we've just got to find a nice E-road bike equipped with Fazua Ride 60. I've got a feeling it won't be cheap! A test ride will still be needed to check that one gets a full four seconds of Boost before one has necessarily pedalled a full circle.

Maybe. It depends on what you had in mind exactly. A requirement to hide the battery inside the frame however, seems to rule out conversions.

Eddy's really looking for a ready-made E-bike with battery discreetly stowed INSIDE the frame, not a conversion.

He's a big guy, but mostly bone and muscle.

This time I really am 'asking for a friend'. My friend - let's call him 'Eddy', not his real name but he'd like that - is fundamentally a very strong rider, who regularly rides more than 100 miles in a day and goes like a locomotive on flat or undulating roads (where the rest of us form up like carriages behind) but struggles on climbs due to a gammy right leg. Eddy's left leg does it all really and once he's up to speed momentum keeps him rolling. But gravity sucks . Drag increases, momentum decreases and eventually Eddy stalls between left pushes. And once Eddy stops, he cannot easily re-start. Starting is dodgy enough at any time or place for Eddy: his right leg can neither push the pedal down hard enough, nor provide a steady prop to stand on while his left leg does the job. On a hill his only option is to point the bike downhill then do a U-turn. Not very safe - and Eddy really does not like to stop at junctions, for a much better reason than most of us have ! Eddy's recently got an E-bike and it helps keep him moving uphill, but on anything much over 15% (1:7) the motor stalls too. And here's another thing: we ride in the Derbyshire Peak District, where the hills are fiercely steep. It's just too route-limiting for us to avoid the double arrows that Ordnance Survey sprinkles generously over our local lanes - indicating 20% and even steeper gradients! This E-bike (it's a Ribble) has a Mahle hub-motor. I guess the current and torque increase the slower it rotates, but only up to a point and surely that drains a battery faster than a motor that keeps spinning at its most efficient rpm? I'm thinking Eddy would do better with a bottom-bracket drive, where both rider and motor get an easier and more efficient ride when a lower gear is selected. And the Mahle system does not offer start-assist, not at all. I know, I asked Mahle if a different controller was available that did that, but no. So I'm wondering, does Fazua offer start-assist? Or is there another super light and efficient 'stealth' e-bike system that does? What would anyone recommend for my impressive friend? Remember, Eddy can go faster on the flat with his one good leg than most of us can with two. He doesn't need any help with that, just for starting and the steep stuff. And it's still got to look and ride just like a pure muscle bike. Nothing less will do for our Eddy .

Apparently what I want is specifically allowed in Germany and called 'Start Assist'. I received this informative reply to my post on another forum: https://1-gd--systems-de.translate.goog ... _tr_pto=sc Shucks. It seems like I'd be wasting my money on a Bafang programming lead and my time on trying to get it to do what I want. Unless someone on here has actually done this themselves and can tell us exactly how they did it! One avenue may remain open to me. I could bite the bullet of removing or bypassing the Bafang motor's integral controller and fit an alternative controller in the space provided for such, in the carrier-fitted receiver of the (non Bafang) 36V/13Ah battery I chose for this build. But: has anyone here actually done this? And did you succeed in getting a workable start-assist function out of it, in addition to normal and legal operation of the Bafang mid-drive?

By "standard KT controllers" do you mean the controller that is neatly integrated already with the Bafang mid-drive? I'm afraid I wouldn't be happy about extracting that and swapping it for some other, separate controller, although there is space provided in the battery receiver for one. However, if the included controller does nevertheless allow the throttle (when limited to 6kmph) to provide full torque without pedalling up to a speed close to 6kmph when the maximum pedal assistence level is selected, that would do fine. Helen can easily tap the assistance level back down to where she wants it, once safely under way. From your experience, do you think that would work?

Same one. I didn't think there were any other 250W Bafang mid-drives currently available (but I guess there must once have been a BBS01A).

Thanks for that information. I didn't imagine for one moment that it would be possible to limit the throttle to a different speed than pedalling, but I can see that if it's limited to 4mph, the throttle becomes legal as a walk-assist control. That'll be perfect - even better than my idea of a starter button!

I've recently electrified my wife's bike. I did my research and fitted a Bafang 250W mid-drive motor with 40T Lekkie 'bling-ring', whilst upgrading the rear shifting to 11-speed in order to get a low-as-easily-possible bottom gear via an 11-51T cassette. It's great, she can now ride up anything Derbyshire County Council cares to spread tarmac on and a lot that they don't - although we haven't yet tried it on Bamford Clough! That's provided Helen can start somewhere flat-ish and doesn't have to stop for anything partway up. For good reasons I won't go into here, although she's a most experienced rider, starting off has never been easy and lately she's become unable to launch into the saddle until the bike is well under way. I hoped that E-assist would help with that too, but it hasn't. If anything, the extra weight has made starting more difficult - especially uphill. Here's what happens: the right pedal goes down, the bike goes forward and does receive a nice little electric boost - that immediately dies away, because the pedals are not moving any more, so the bike slows down again before she feels sufficiently confident to commit. A higher gear works better, that and max assist gives enough of a push, enough speed that lasts just long enough on a slight upward slope, for Helen to feel that the bike is moving well enough to risk putting ALL of her weight on that downward pedal, sit on the saddle and find the left pedal with her other foot, then PEDAL! That's improving her starting confidence, but I can't see it ever being enough for the really steep hills, where the the bike stops very promptly once the right pedal is down and there's no more power. By the way, I have set the controller so that power kicks in after only one pole has passed the cadence sensor. I thought that walk-assist ought to do the trick. If the bike would just go at walking pace, that should nevertheless be enough for Helen to commit and pedal on. But sadly, the Bafang mid-drive's walk assist mode seems to be limited by chainwheel cadence, rather than actual road speed, to a slow enough motor rpm to ensure that 3.7mph is not exceeded even in the highest gear that any receiving bike is ever likely to be equipped with! As Helen's bike is geared quite low, it goes even slower than that, even in top - strolling rather than walking pace. And the torque also seems to be limited in walk-assist mode, to just enough to move the bike, not both bike and rider and certainly not in top gear up a steep hill! Can anyone suggest some way of getting into the deep settings of the controller, so as to make walk-assist more speedy and powerful? The display is model 500C. I realise that the simple solution would be to fit the throttle that came in the kit. But Helen doesn't want anything illegal on her bike. And all she really needs is a starter button delivering full power and any legal speed for say three seconds, then cut. I expect you'd get that result by briefly connecting two of the three wires in the redundant-in-UK throttle cable dangling temptingly from the handlebars. But can one buy such thing as a Bafang starter button ready made? I realise that would be illegal too, but a stronger argument could be made for such a gadget, especially if it were designed so it couldn't be pressed continuously and timed out for say 30 seconds, before resetting. I know another cyclist who's lately got an E-bike - that gets him up the hills but doesn't get him started. He's a very strong rider on the flat (we all tuck in behind when Dave gets rolling!), but that's all thanks to his left leg. His right leg has nerve-damage and isn't sufficiently strong or controllable to push the pedal down for a hill start, or to stand on while his left leg does the job. So he points his bike down the hill then does a U-turn. Not easy on any road, very tricky on a steep hill and possible only if the road is wide enough, which most steep hills aren't! A starter button is exactly what Dave needs too and if E-bikes are supposed to help less able cyclists, I think he should be allowed to have one. So does anyone know if it's possible to add such a feature to a Ribble E-road bike equipped with the Mahle hub?

But that's an American site that only talks about the 750W BBS02 and gives a quite different answer (53mm with Bafang chainring) from the drawing courtesy of Whoosh above (50mm). So is the BBS02 fatter by 3mm? Are the people who say that BBS01 and 02 are outwardly identical, plain wrong? Then on a another American website (https://www.electrifybike.com/blogs/news/choosing-a-diy-conversion-mid-drive-motor#tc1) I find a comparison chart that gives an even further out chainline for the BBS02 of 60.8mm when fitted with a third-party chainring intended to make it LESS far out! Which of these two Yanks is right? They can't both be. Confusion reigns - especially when Americans are involved!