Some Bafang BBSHD and BBS02 programming tutorials say Speed Meter Signals must be set to 1 or bad things happen. They are right. They are also totally wrong.
This is going to be a quickee post to show off a little spiff you can do on a Bafang mid drive, and point out something wrong I see in some tutorials or forum posts about Bafang BBSHD / BBS02 settings. Specifically:
The Speed Meter Signal
Put simply: It does not have to be set to ‘1’. But I am getting ahead of myself. Lets start from the beginning:
At the root of the matter is the BBSxx Speed Sensor. If you buy one as part of a kit, or on its own, this is what you get for roughly US$20:
The speed sensor magnet attaches to one of your spokes. You attach the sensor to your chainstay (usually) and position it so the magnet passes close to it as the wheel rotates. The sensor detects the magnet’s passing and calculates your speed, via a rotation count and knowing your wheel diameter via a separate setting.
So if you buy the typical sensor, you get one magnet, one sensor, and you need to set the Speed Meter Signal to ‘1’. Is that setting because you have one speed sensor?
No. Speed Meter Signals counts the number of magnets. Not the number of sensors. Each magnet is a signal. Got one magnet? Set it to 1. Got two? Three (for a 36-hole wheel)? Four? Change the setting accordingly and it works great.
Why do we need more than one?
The one magnet works pretty good as it is, so nobody really gets too deep into this. Plus nobody sells Bafang speed sensor magnets by themselves. So to do this you are talking about roughly $20 per magnet because you have to buy a whole speed sensor assembly.
I have found these can just be tightened onto a spoke by hand, and they do not need any thread locker to stay tight (adding some Vibra Tite would not be such a bad idea). Reportedly these magnets work over a much greater distance than their Bafang cousins, which is another benefit.
Get To The Point!
Fine here it is. Look for the speed sensor magnet in the picture.
There are four lights magnets on this wheel. One every 8 spokes. I have the Speed Meter Signals reading set to 4. The improvement is not earthshaking but I do get the following:
My speed reading on my display updates faster and more smoothly. Quadrupling the signal input is a good thing which is not a surprise.
The Cateye magnets are smaller and lighter by a fair bit than the Bafang magnet assembly. This results in the wheel getting thrown less off-balance than when using that big heavy Bafang doodad (even if you place it opposite the valve stem to even out the weight distribution).
Four magnets placed equidistantly around a wheel make for a more balanced wheel spin. Its minor. But when spinning the wheel with the motor when the bike is up on the stand the lesser amount of shaking is noticeable.
Using just two sensors (the 2-pak of Cateye sensors is only $9.95) gives a noticeable improvement as well. Enough that 4 sensors is not noticeably better or worth even the minimal the cost/effort. I can’t help but think that two magnets means two points of potential failure rather than four. This weekend I’m going to go back to two magnets.
You can take this tidbit as useful in a couple of ways: A cheap, lightweight, stronger magnet replacement or a way to get a better speed signal to your display.
Its not a big improvement, but it is a nice little one.
With few exceptions, everyone who can ride a bicycle already knows how to ride a hub drive ebike. Not so if it has a mid drive. Particularly a powerful one that can tear your chain apart. Here is how you flatten the slope of that learning curve.
“Mid Drives For Dummies”
This article is based on a portion of this post where I discuss the strength and weaknesses of different types of ebike motors. I link that article many times in help discussions, but usually only for the part about how to ride a mid drive without excess drivetrain wear, mechanical failures etc… so I am creating this standalone post on the subject… and stealing liberally from the original.
Mid drive motors on ebikes are very common in the production-line, name-brand-manufacturer ebike world. Its safe to say they dominate the industry for eMTBs. Why is this?
Hub motors power the bike thru the axle, so they are single-speed: their motive power has nothing to do with the chain, chainrings or cogs. Try taking off your chain and then go pedal the bike around. Pedal assist will work just fine. The chain and chainrings are only there for you to slug it out with; the motor couldn’t care less.
Since hub motors are single-speed, that means they are not happy climbing hills… for the same reason your life sucks trying to do the same thing with no gears. The only fix for this is to run thousands of watts thru the hub (we are talking 3-6kw or more, which is approaching e-motorcycle territory).
Unlike hub motors, mid-drives power the bike thru the drivetrain. They use the gears just like you do. This is a good thing for the same reasons its good for you.
Only a fanatic or a penitent rides hills on a single speed bike. So how is it desirable to do that with an electric motor? Spoiler Alert: it’s not. A single speed hub motor is often strong enough to help get you up that hill. But its not happy doing it, and its not good for the motor or (if it has them) the gears inside of it.
If you have only had a hub drive ebike you won’t realize just HOW unhappy until you take your first proper ride up a steep hill on a mid drive ebike. Get it in the right gear from the start and the bike simply doesn’t care that its going up a hill. It scoots right up without breaking a sweat.
The benefit is multiplied when you look at a mid drive’s motor specs. Usually they are more powerful than a hub drive by a wide margin. A typical hub puts out 40-60 Nm of torque, with a few going up to 80 Nm. Production mid drives usually start there as the bottom end. Aftermarket motors commonly put out 120-250 Nm.
Well, if you aren’t familiar with what it means to have X Newton Meters of torque going thru your drivetrain, lets use the more common (but functionally useless) measure of watts:
That 180Nm motor pictured above has a peak output of 3000 watts.
A BBSHD or a Bafang Ultra peaks at 1750 watts (peak power on the BBSHD can also be maintained continuously so its REALLY a beast).
A 48v BBS02 is about a thousand watts.
your typical street-legal pissant EU motor is rated for 250 watts (pssst… the manufacturers are now all cheating on this. Don’t tell anybody).
A normal cyclist on an analog bike is capable of putting out roughly 300 watts over the span of a few minutes.
Yeah ‘oh’ is right. Your mid drive is pumping a metric shipload of power thru your drivetrain. That power is likely more than standard bicycle parts were meant to handle. So how do you have a motor this powerful (its not as much of a boost as the math makes it sound like) and not bend, break or snap stuff?
It Ain’t Hard To Do Right…
…but you gotta do it. Here then are the rules of the game when riding a powerful mid drive motor.
The Short Version: Keep the motor spinning.
Now the Long Version:
Keep The Motor Spinning
Here’s a basic tenet that is true of all electric motors: Electrical power goes towards turning the motor and producing forward momentum. If there is resistance – which keeps the motor from free-spinning – then instead of forward rotation, the electrical energy is converted to heat. Mid drives have so much power that they can get really hot, really quick if not allowed to spin up. But they are so powerful, they might not just stop at generating heat.
Lug a powerful mid drive and the torque that is pouring out of it could tear your chain apart – if it can’t rotate it thanks to resistance. Or, you might discover what it means to ‘taco’ your front chainring or rear cog. If your sins are not quite that egregious, and you just lug it gently enough to not tear something apart, then within the span of a single ride it can ‘peanut butter’ the nylon gears inside your motor; bricking that motor and potentially requiring you to carry the bike anywhere you plan for it to go.
Thats very, very bad. So don’t let it happen. Here’s how we do that:
When Coming To A Stoplight, Downshift!
Always. Either that or stay in a gear that is in the middle of your cluster so when you start up again, the motor does not lug itself. You spin up quickly, without any brutality being visited on the drivetrain.
From a standing start, a mid drive will slowly tear into the cassette body, or damage the pawls inside. this will eventually tear the freehub apart and kill the hub. Which means you get to build a new wheel.
If you downshift so the motor doesn’t tear into your drivetrain when you start back up again, you’ll be fine. So remember: downshift before you come to a stop.
This is a gear cluster. Each wheel is a 'cog'. Smaller cogs are higher gears (you go faster). Bigger cogs are lower gears (slower, distributes torque, gentler on the chain). This cluster is a SunRace CSMX8 11-46T: The smallest cog has 11 teeth and the largest has 46.
When You Want to Go Faster, Upshift
When working a mid drive, just like driving a classic sports car, you have to ‘row’ through the gears, both slowing down and speeding up. Wait until your motor is maxed out before you kick it up a gear (up = a smaller cog in the back). Chances are good its going to be smarter to stay one gear down from what you would have used without a motor (down = a bigger cog in the back). Why is that? Your bike will spin up to the same top speed on its next-highest gear (the next-bigger cog in back) as it will the highest one: But it will get there faster if you let it use the bigger/lower cog next to it. Mid drives are like that, especially when going fast on the street. Here again we are going back to not lugging the motor, and letting the mid drive spin faster than you ever would. Unlike you who has to do the pedaling, they like it that way.
Again thinking of your mid drive ebike as if its an exotic sports car with a manual transmission: In between each gear you need to let off the power, shift and hit the accelerator (the throttle). If you have a gear sensor you will not have to worry (officially) about the ‘let off the power’ part as that will be safely done for you.
Note that above, I am talking exclusively about when you are using the throttle. If you want to pedal the bike thats no problem… just use pedal assist and set your power level to a lower setting. Take care not to overdo the boost, and keep your legs spinning fast via smart gear choices – just like on a regular bicycle – so you never lug the bike with slow pedaling up a steep hill
If you are pedaling slow on flat ground, or downhill, you are not providing resistance to the motor or pressure on the chain. So there is a lot less to worry about there insofar as cadence or lugging the motor is concerned. You do however need to make sure you ALWAYS do the following no matter what the terrain is:
Do Not Shift Under Power
Even if you have a gear sensor. Thats right I said it. Don’t trust the gear sensor unless you are forced to. Lift for just a sec and do your shift.
Shifting while pouring huge watts into your chain is an ugly thing. You will recognize your mistake the instant the result hits your ears. It won’t kill the chain outright, but as you hear that chain smash from one cog to another you will know your bike hates you very, very much.
If you treat the gear sensor as a fail-safe rather than taking it for granted, you will be much more likely to avoid disaster. Now, as you become familiar with riding your mid drive and how it behaves, you will naturally figure out how to push it to its limits and minimize that power blip when you shift. You may even get smart enough to do without the blip entirely and just shift full throttle. But for your first few weeks of riding this thing… treat the gear sensor as a backup, not the default.
Here’s a technique you want to learn as part of your education on operating a mid drive: Using your brake lever motor cutoffs as a clutch: Just slightly actuate the levers so the cutoff kicks in, but the pads don’t engage. Lift when the shift is finished. You can stay on the throttle or keep pedaling while doing this so the process is near-seamless.
Many ebike levers have this ability built into them. Magura MT5e levers have a mid-lever hinge that lets you touch the brakes and engage the cutoff without any pressure making it to the caliper.
Keep Chain Alignment As Straight As You Can
Mid drive motors tend to work in a lot wider range than humans do. So you can leave the motor in a gear that would be too low for your cadence and let it spin away like crazy… it actually likes it that way. So, this piece of advice is partly about how you ride the bike (i.e. what gears you let it sit in) but also about how you build it if its a DIY effort.
You really only need three or four gears in the middle of your cluster on a mid-drive-powered ebike. You want them to be the ones that let the motor spin fast. You also want the cogs the bike is happiest in rpm-wise to not be cockeyed, front to back (i.e. bad chain alignment). So regardless of whether you built this bike or you just bought it, when hammering on the power don’t do it when the chain is yawed to an extreme.
On an analog bike you can get away with a lot, since you are only feeding back 150 watts to it. Feed it 1500 and that sideways-skewed chain will become a saw and chew right through your front chainring and rear cog teeth. Be smart when you shift your gears (or when you build the bike in the first place).
If this is a DIY build, learn in your first outing or two whether there are any problem gears you should stay away from. There are all sorts of offset chainrings (and 1mm and 2mm shims) available on the market. They cost money, but spending that money now means not spending it later after you have walked home.
If you bought your bike manufactured with a mid drive installed from the factory, this part has already been taken care of. If you are building an aftermarket conversion, you will have to buy components that are strong enough to handle the punishment your 1500w+ motor will mete out. Almost 100% of internet whining about mid drive reliability is from builders who fail at this stage.
If you build with appropriate components, and ride it smart, even a high powered mid drive will essentially last forever. Yeah sure you will wear out the chain and rear cluster in say three thousand miles, the smallest cog in half that, and the chainrings in 10. But thats peanuts considering how many miles you put on the bike.
Since I got back into bikes (thanks to ebikes being a viable platform to let this cardiac-issues ex-cyclist start riding again), I have gotten right back into building bikes up, oftentimes from scratch. At this point I really have to stop simply because I have no more room to park the things.
Up to this point I have only written about my Mongoose Envoy, a very recent arrival, and have just begun getting into my Surly Big Fat Dummy, which is more recent still.
What else is in the stable? I’ll do some very quick mentions here and then over time branch out and describe each more fully in separate posts.
The Lizzard King
So named because thats the name Larry vs. Harry gave this green color of their Bullitt cargo ebike. I bought a frame kit from Splendid Cycles up in Oregon in January of 2021, and did an all-out AWD build on this bike which I completed in March of the same year. That included putting in a basement that holds a secured (big) battery. This will be a bike that gets fairly extensively written up. For now I’ll just drop this note that the bike exists, I’m riding it, and here’s a couple of pictures.
The Great Pumpkin
So named because of its very nice bright candy orange color (done at a local powder coat shop for next to nothing) you can call this one my third generation of 2wd bikes. Twin 35a controllers. A single custom-built 30ah 52v (14S9P) battery with a BMS able to handle 90a continuous current. Twin 750w-rated geared hub motors that commonly peak (each) at over 1700w. This bike accelerates like a bullet if I let it do so. But to keep the frame in one piece and me from being launched into traffic I have toned down both motors. Now I am merely the first vehicle to the other side of the intersection after a stoplight turns green.
It has synchronized dual pedal assist as well as brake cutoffs that individually shut off both motors on application. It has thousands of miles on it; all street commuting. Gearing is set up for 34 mph at about 70 rpm cadence. That is just a bit faster than the motors can power the bike, so if I want to cruise down the street at 30+ mph I have to work at it a bit more than you would think for a fairly high powered ebike. I get a strong workout due to this gearing.
The frame is a chromoly Chumba Ursa Major, with a Surly Ice Cream Truck front fork where the brake adapter on that fork was specially modified to get around the ICT’s rear-wheel brake spacing.
While the build of this bike pre-dates The Great Pumpkin, it was actually designed as a next-gen design to follow another 2wd bike (see the Purple Thing below) that pre-dated both bikes. So if the Pumpkin is 2wd 3.0, this one is 2wd 2.0. This one does not have the single unified battery, and its handlebar config is not as well done (two clocked-position throttles are on the left grip instead of one on each thumb… I hadn’t discovered shifters that would allow me to do the latter yet). However, it also sports a 30a, 1750w mid drive powering the back, and has the same fat hub motor as the Pumpkin powering the front. It too has dual pedal assist, but done in a completely different way given the dissimilar motors and controllers. 2Fat was created because of the learned weaknesses of even a powerful dual geared hub design in hill country. 2Fat was designed to climb walls effortlessly, and it will, without issues of overheating or strain.
100mm custom wheels with a DT 350 Big Ride ratchet rear hub and steel cassette body, Lynskey titanium frame is a prototype made along the lines of Chumba’s Ursa Major ti version of that frame. Possibly it was made as part of a pitch by Lynskey to make the frames for Chumba. Its hard to say for sure so essentially, the frame is unique, or close to it. I do know it is visually almost identical to the Chumba production models except the dimensions do not match any of their production frames.
A big departure from my usual bikes. The Smash is a 29er … and a bike with no job. With a 3kw Cyc X1 Pro motor, a 50a ASI BAC800 controller and a 20ah 52v backpack battery, this bike is strictly a hot rod. And no, despite those big power numbers its not as powerful as you might think. Certainly it doesn’t tear up trails. This is one of the last alloy frames Guerrilla Gravity made before switching to carbon fiber later in the same month I placed my order. The MRP Ribbon fork on the front is a jewel. Also has a RockShox coil spring, a complete SRAM EX drivetrain and my usual Magura MT5e brakeset.
I’m glad I took these pics right after the build was completed because it will never be this clean again. Ever. Also the pump location and top tube bags only lasted as long as this photoshoot as they violated my ‘festooning’ rule.
So named because of its black/white color scheme. The Stormtrooper is just a really nice, simple fat tired ebike – with deep dish 90mm carbon fiber rims. Noteworthy on this bike is that it has plenty of motor and battery cabling running all over the place, but I sheathed the wires (even the brake and shifter lines) in white heat shrink. The matching color effectively hides all the wiring in plain sight for a very clean look. the bike is light and fun, with good range from its mid-sized 12ah potted ‘indestructo’ battery.
This frame was a rescued Motobecane Lurch that was stripped, sand blasted and powder coated.
One of the few bikes I have written up here, The Mongoose Envoy has its own extensive writeup already. The Pacific Fleet’s first aircraft carrier thanks to the 44″ skateboard deck.
The Big Fat Dummy
One of the more recent addition to the Pacific Fleet, The Surly Big Fat Dummy is its second aircraft carrier, with a 40″ skateboard deck (and below-deck hangar) putting the length of this behemoth at just over 8 feet. This bike has a complete and detailed writeup here.
In no particular order, the ships that are no longer in the fleet
An even bigger departure is my Luna Fixed, which despite having custom DT wheels, is largely a factory bike and was bought primarily as a test platform. I fell in love with the design concept (stealth ebike), but it also had an internally geared hub, a Gates belt drive and torque sensing. These were three technologies I had yet to experience and I decided this bike was going to be how I learned about all three on one bike.
Its the only ebike I have ever ridden that feels like a road bike from the 1970’s. I re-did the handlebars to a more urban narrow config, added bar ends, changed the stem, saddle and pedals… not a lot else. Its for sale It was sold on eBay as I’m largely done with it, its still effectively new and I never ride the thing. I’ve always been a commuter and a utility rider and this bike is purely a leisure exercise, or for someone who needs to make a quick store trip and doesn’t already have a stable of bike better suited to the job.
I will miss one big thing when it sells: Its the only bike I can just toss into the back of my SUV and not make a major production out of loading onto a super heavy duty bike rack. Like recreational riding, I don’t do that either but someday I bet I wish I still could.
Now in the hands of a friend who needed a ride. Frankenbike was cobbled together from leftover parts from an upgraded electric bike, plus other goodies. It was my first 2-rack cargo-oriented bike. I painted the frame myself using Main Force Pursuit (MFP) Yellow. Google that if you don’t get it. The frame is identical to the Purple Thing, below.
Murdered by a careless auto driver who t-boned it and me while I was thoughtlessly riding slow in the bike lane with headlights and after making eye contact. The Stump was a little hotrod that never made it past the initial shakedown cruises before its demise. Paid for by the other driver’s insurance company but left in my possession, I donated the damaged but still fully functional motor to another cyclist who could make good use of it
The Purple … Thing
Essentially this was 2wd 1.5. I transferred my parts from the 2wd 1.0 bike when I cracked the frame, and made a few improvements. Since it was an emergency build to get my daily commuter back on the road, I didn’t do a lot of measuring and took what I could get framewise. It didn’t quite fit me and a year later one of these motors and some of these parts moved to The Great Pumpkin. The frame is still sitting dust-covered in a corner of my garage.
The bike that got me started back on two wheels again and changed my life for the better. A Sondors Original fat ebike whose cost was so low at around $700, I was willing to toss the money out the window and take a chance this whole ebike thing was going to allow me to get back onto a bicycle. By the time my first year was up I had put more than 4000 miles on it. I had also changed out almost every component but the frame, and converted it to all-wheel-drive.
The Colonel died with his boots on. After almost 6000 miles on the road, supporting a whole lot more power and speed than it was ever designed to bear by its original Chinese overlords, the rear seatstay cracked at the lower rack boss. My philosophy on frame cracks is not to repair them as where there’s one crack there will likely be more showing up soon. Components were transferred to The Purple Thing along with several upgrades.
Well, I don’t actually hate it, but I have no love for a technology rooted in cycling’s past, and whose existence, in my opinion, is primarily owed not to the fact that torque-sensing is a better system, but instead as a tool to help persuade an existing customer base (recreational cyclists) not to hate the product (ebikes) quite as much as they already do (either that or to sell ebikes while not cannibalizing sales of their analog brethren).
What is Torque-Sensing Pedal Assist?
On an ebike, when a torque sensor is used, it applies a strain gauge to the drivetrain (located either inside the bottom bracket, or in the back of the bike near the gear cluster). This measures the amount of force you apply to your pedaling stroke. If you pedal (work) harder, the assist you receive is dialed up. If you pedal more softly – regardless of your cadence – the assist level is reduced… or eliminated.
I have heard it said that torque-sensing “rewards pedal effort” and this statement is both correct and indicative of the root problem with its advocacy. Old school cyclists hate Hate HATE the fact ebikes allow someone to make forward progress without using their muscles in the first place. By restricting/keying the assist to physical exertion levels, the fact that a motor exists at all is less difficult to accept – and more easily sold to the existing cyclist population.
It also allows an ebike to be sold without denigrating the old-school unassisted version. Zillions of which are still manufactured for sale worldwide. If torque sensing just makes it seem “more like a regular bicycle” then that helps preserve the perception that a normal bicycle is still every bit the desirable, viable product that manufacturers still need to sell millions of.
It is unfair to say torque-sensing is ONLY about these things. Its not. You will also hear people say torque-sensing results in the most ‘natural’ bicycle riding experience for them, since you still have to work hard on the pedals. And the assist increases in proportion to your effort, just like a real bicycle. An ebike goes faster of course, but a physical work ethic is still demanded. So to be fair, torque-sensing does indeed give cyclists who want this a familiar and desirable experience. There is nothing wrong with that.
What is Cadence-Based Pedal Assist?
In its simplest form, its nothing more than this: Your assist level goes up or down based on how fast the crankarms are turning. The amount of effort you expend could even be irrelevant if your gearing is low enough. The only thing that matters is the rotational speed of the pedals/crankarms (strictly speaking it is the spindle’s rotational speed that is measured, but thinking ‘pedal rotation’ is easier to visualize).
So if you want more assist, you just turn your legs faster – not harder. Again in simple circumstances this means you can get into a low gear and easily ‘ghost pedal’ your ebike, without expending any effort. So you are breezing right along right up to either the speed limit of the ebike or the road/path you are riding on.
Such a thing is utterly anathema; deeply, personally hated in the cycling community. There, your progress and ability is hard earned through what can only be described as prolonged, personal, stoic suffering whose level outsiders neither understand nor hope to match. Despite the spandex, funny hats and silly shoes, cyclists know they are endurance badasses (they really are).
Except, fate has dictated these solitary warriors suddenly have to share the road with the Griswolds, blowing past them in their two-wheel Trucksters. Ebikes democratize cycling so that now… anyone can do it? WTF!?!
… not a shock the response of cyclists to ebikes has been negative.
Its not so simple
I said above the description of cadence-based pedal assist was in “its simplest form”. There are some cadence-sensing ebike motors that have settings both complex and rather profound in how they impact the riding experience. Notice I did not say ‘cycling experience’ because a central tenet of my rejection of torque-sensing is that ebikes are not bicycles. It is a mistake to treat them as if they should behave the same (unless that is something you expressly want).
If you have a physical limitation, torque-sensing doesn’t help you get past it. It does help you go faster while working hard. Studies have shown that ebikers in fact can work nearly as hard as, or even harder than bicycle riders… they just don’t realize it. Possibly this is due in part to the exhilaration of being able to go faster, and stay in the saddle for longer periods.
Myself, I am a lifelong cyclist. Or rather, I was. I commuted daily for decades. For many years I eschewed the use of an auto. I commuted and even shopped for groceries by bike (being poor and single had nothing to do with this of course). But after a couple of heart attacks, my cycling life was over. To stay alive, I gave up the intensely personal activity I most valued. Bummer.
A few years ago, I discovered ebikes, and the one I bought had cadence-based assist. I had no idea there was another kind of system at the time. I did something many old-schoolers do not: I treated the ebike – which looks like a bicycle but is not one – as a new animal. I threw out much of of the knowledge on cycling I had acquired, and started over on riding technique.
At the start, pedal effort very quickly led to chest pain and an immediate need to stop doing that. But I could go on if I incremented up the assist and incrementally lowered my pedal effort. This allowed me to keep going (maintain forward progress).
I learned to treat the ebike like an exercise machine. An exercise machine that went places and was practical transportation. Instead of directly coordinating effort with forward motion, I separated the two. Effort was always maintained, and so was clicking off the needed mileage to my destination. But the two no longer had a 1:1 relationship. This decoupling of effort vs. speed solved everything. The procedure in a nutshell is as follows:
Set a preferred cadence
As heart pain occurs (heart pain /= being tired) click up the assist level so I get closer to or completely ghost pedal the bike – and keep moving
On recovery – I’m good after maybe a half block – ramp down the assist level a click at a time and start working harder again
All the while maintain the same cadence
Rinse and repeat as the miles click off to destination arrival.
Again, to belabor the point: This is transportation. My bike has somewhere to go, so the point of cycling is to reach a destination. If I was a recreational cyclist then maybe its fine to stop and sit on a bench for awhile. But the point of riding for me is to get somewhere. So I must maintain forward progress while managing my exertion level.
Only cadence sensing is going to let you do that (and I know this from experience. See Afterword below). Its a different riding experience described most simply as an exercise machine that is moving. Again… not a bicycle.
Different But Still Good For You
Over time and thru repetition, I scaled back the point where pain occurs to where I was able to change my bike’s gearing. Now I’m running at top assist speed while maintaining pedal pressure and exertion at all times during the ride. On my Class 3 daily driver I cruise right at 28-30 mph (legal in my jurisdiction) and I get to those higher speeds above the assist limit by myself. All along doing so by maintaining a set, preferred cadence.
And if I overdo it, since I am now running this auto substitute at full power, I can just upshift (maintaining cadence on the easier gear) to take a break while only losing a mph or three. This is a different way to use cadence-assist. I am not dialing back power: I’m always running at full blast. Instead I am just varying my pedal effort up and down via gear changes.
What happens to a rider with physical restrictions who tries to depend on a torque-sensing ebike for transport? You ride, you need a break, you want the bike to help and… the bike tells you to fuck off. Unless you work hard enough to deserve a reward, it refuses. So much for dependable transportation.
Broadening The Use-Case
Cadence sensing isn’t just for recovering invalids. For the healthy rider, successful use of cadence-based assist as a hard-exercise tool is easily possible, and rooted in that rider not coming into the experience with pre-conceived ideas. Don’t treat it like a bicycle (yes I am repeating this over and over on purpose).
Using the ebike as an exercise machine as you roll down the road, you’ll be getting fit during time otherwise spent sitting in your car and exercising nothing. A torque-sensing ebike can do this too… but if the ebike is meant to also be practical transportation, your physical condition of the moment will have a direct impact on whether you make it to your destination. Not so with cadence assist.
It took 34 years for the Tour de France to allow bicycles with derailleurs — because not grinding up a slope in the Alps on a single-speed was cheating.
… Isn’t it better to triumph by the strength of your muscles than by the artifice of a derailleur? We are getting soft.
-Henri DesGrange, world-renowned cyclist and original TDF organizer
If someone tried to make that same case today, their opinion would be seen as fringe idiocy.
So lets take that same interval: 34 years from now, when ebikes have long-since become the accepted norm (just look at the sales figures) as derailleurs did a century ago… will we be espousing technology or methods rooted to the norms of the past? Will a couple of generations of riders who have known nothing else continue to think of torque-sensing assist as giving a bike a ‘normal’ feel?
My money is on ‘no’. Or more accurately… sorta-kinda-no. I think for higher end bikes a dual system could become commonplace, letting riders choose one or the other as they see fit in the moment. One mode for recreation. One for transportation.
If it has to be a this-or-that binary choice, I think torque-sensing won’t survive the test of time. Why? Sheer weight of numbers, and the growth of the automobile replacement market. Look at global ebike sales. Only a small fraction of ebikes are sold in the European and North American markets, where recreational cycling is a thing. Look at the Far East, where bicycles are simply utilitarian transportation and there is no stigma attached to effortless travel. Whats the norm there?
UPDATE (February 2021): Its already happening through a vector I hadn’t considered. Recreational ebike riders are starting to upgrade from their cadence-based budget bikes to what the industry tells them was the ideal product: a better bike with higher end components and… torque sensing. I’m seeing reviews from riders not inculcated in traditional cycling ethos, saying the bikes are no longer fun. They can’t just get on a bike and zip around and enjoy the outdoors for as long as the battery holds out… now their bike is making them work at it. What was once an unconsciously-achieved benefit (exercise) is now an enforced requirement. Riders like this, new to the fold, don’t always appreciate the new rules. With the pandemic rushing literally tens of millions of new riders into the fold, the spread of this effect could manifest itself far more quickly than the slow evolution I originally anticipated.
Lest I give the wrong impression… I have an ebike that uses torque sensing, and frankly I love it. But its a recreational bike, not suited for a bike that has a job. Going for a fun ride, where I don’t have a problem stopping and sitting down on a bench or a rock for awhile and enjoying my surroundings… Its almost perfect for that. I wish I had time to ride it more.
But by its nature it can’t be a serious transportation tool.