ElectricMotorcycleForum.com
General Category => General Discussion => Topic started by: SgtMickle on December 28, 2020, 11:58:50 AM
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I've seen a few posts from several years ago referencing this, but I wanted to bring it up again since it seems like a huge problem that more people should be talking about.
The Zero bikes are extremely powerful with very high torque (that's instantaneously available). With no traction control, they're prone to sliding out when given a lot of throttle, and even prone to highside crashes if the throttle is chopped mid-slide (see below for video examples). This differs from gas bikes with no TC, since a) the electric bikes generate much more torque than most such gas bikes, and b) the gas bikes build up torque gradually, rather than pumping it into the rear wheel instantaneously when the throttle is pinned like the zeroes do.
I fell victim to this recently - I was riding (seemingly perfectly straight!) on my 2021 SR, and when I pinned the throttle in sport mode, the bike just completely slid out from under me. I ended up in the hospital and the bike in the shop, and after it was repaired, I've kept it in eco mode (w/ reduced power) ever since. It seems like the bike can just lose traction from its own power, and it gives you absolutely nothing to protect against that.
Zero is selling death traps - to anyone considering, I'd strongly advise avoiding these bikes until they fix this. Go for an SR/S or SR/F, which do have TC, or choose another brand.
I'm very curious how many people this has already killed, since it seems to be a commonly reported occurrence among zeroers.
Here's some examples of this happening (you'll need to fix the spacing on the links):
Highside crash:
www . youtube.com/watch?v=fDtwUDnsHA0
www . youtube.com/watch?v=IhpA7Raj_Zc
"I only had it for three days... that is the first time I have ever crashed" (see 3:58):
www . youtube.com/watch?v=DPJyCjlYGXU
"I don't know what happened! ... It was just going in a straight line, and all of a sudden..." (see 17:16)
www . youtube.com/watch?v=QmSR0zuWubA&t=1036
Another:
www . youtube.com/watch?v=d1zcLltukUY
And then there was my own crash experience. Anyone else have something similar happen to them on a zero?
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I'd be surprised if there are many deaths (there's bound to be at least one) because it mainly happens at lower speeds. The funny thing is a decently powerful gas bike will actually have more peak torque at lower speeds, in first gear, than many electric bikes. However like you say that torque isn't instantaneous so the rider on the gas bike would need to rev the bike high and then drop the clutch to break traction (unless it's a particularly powerful bike), which I have seen many examples of.
I wouldn't say they're death traps, they're perfectly capable of being ridden safely (as safe as a bike can be) once you get the hang of it and dealing with a loss of traction becomes second nature. To a new rider, or one coming from a gas bike, they are indeed more likely to have an accident because they are more sensitive and this is the reason that everyone recommends lowering the power and gradually increasing it over time (and lowering it back down when the conditions require it).
I've only ever had one accident, a low side, and that was on my 125. That was also my only experience on gas bikes. I've been riding my DS a bit over a year now and I've spun up the rear wheel a fair few times (sometimes on purpose) but it's always been manageable. Part of that could be down to luck but I also know my throttle control and reactions have improved.
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I'm convinced they're only dangerous to gas-bike riders with decades under their belt, as they're the only ones I hear of ever doing this.
Nothing here isn't something that couldn't happen to a gas bike - you fall and the weight goes to the throttle and the wheel will spin up no matter what. Same for going over a manhole cover or puddle. You just let go of the throttle and you'll be fine.
I don't know that they're 'more likely' or 'death traps'. Zero S and FX are sold as a trainer bike in the EU, and they're pretty tight when it comes to regulations.
-Crissa
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I don't think the Zero bikes are dead traps that need to be avoided.
I come from a Honda VTR 1000F, if you want to talk about death traps. But to be honest. In my opinion it is the driver that needs to learn to control the bike.
The Zero has an eco mode, so it has a “safe drive mode”. I can imagine it is dangerous to drive in sports mode when you usually drive in eco mode. I only have my bike for about 2 months now and I too went for a fully opened throttle in sport mode. And yes it was spinning like hell. Now I know I need to learn about opening the throttle responsibly. Learn how fast I can open it at different roads/ road conditions. (The dealer also warned me and asked me if I know how to handle a bike with a lot of torque.)
Traction control would probably prevent me from getting in dangerous situations when I do something wrong. This probably holds for any bike. So I think it would only be fair to avoid all bikes that do not have traction control.
The difference between the electric bike and a gas bike is the clutch in this situation. Where I would start spinning on my 1000f I would immediately pull the clutch (as I was taught at driving school.). By doing so my rear wheel would get a change to find grip with the road.
An electric bike does not have a clutch, so the only thing you could do is putting the throttle down to 0. If I am not wrong sports mode has no to little repetitive breaking when you put the throttle to 0. So it should be similar to pulling the clutch.
Summary of my opinion
- It is possible to drive safely on a zero
- I think the zero behaves similar to a bike with gas.
- So if we would avoid bikes without traction control, we should avoid all the bikes. Not only the zero.
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Motorcycling isn't the safest activity that someone can participate in. Yes I understand and know about no traction control on Zero's. I wiped out several years ago at Deals Gap on my SR when the back tire broke lose when I pinned the throttle. Never thought of them as death traps and fixed the broken things, mainly right side foot peg and just kept riding. Lack of traction control isn't what you need to be worrying about on a Zero or any other motorcycle, its distracted drivers which I am sure are responsible for far more motorcyclist deaths.
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For the S platform, 'Sport' seems to be high torque high throttle regen low brake regen while 'Eco' is low torque, middle throttle/brake regen.
Personally, I ride with middle torque, low throttle, high brake. But that can cause the rear tire to skid in wet for both high acceleration and heavy braking. But otherwise, it's usually pretty safe.
I expect it to do the things it does, because I have always ridden that way. But I don't expect a clutch to save me... Which may be the difference. Heck, driving my (manual) car I wouldn't expect my clutch to save me if I spun the tires in a turn (which I've done, many a time).
-Crissa
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This is a non-issue that keeps coming up and wouldn't be a problem if people LEARNED HOW TO RIDE PROPERLY! For almost a hundred years not one single motorcycle came with any traction control beyond the rider's brain connected to the throttle. Modern riders seem to have forgotten that the throttle has an INFINITE number of settings between no throttle and full throttle. We should learn to use our God-given brains to read the road and identify the correct amount of throttle to apply in every situation. Because of their electric motors, Zeros are EXCEPTIONALLY easy to ride this way, unlike the two-strokes of the old days that had very little torque until they suddenly came on pipe and had massive amounts of torque (ask anyone who owned the ORIGINAL Kawasaki H1 or a Yamaha RD350 about that).
Instead of handing over our decision making to computers (something a distressing number of our population is willing to do these days) we should be honing our skills to be better riders and not count on electronics and computers to save us from our own ineptness and stupidity.
This former MSF Rider Coach is stepping off his soapbox now. Oh, and GET OFF MY LAWN!!!
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I have been riding motorcycles almost every day for the past 58 years and all but my current BMW RS did not have traction control. And only a couple came with ABS. I even special-ordered my BMW F650GS without ABS, as I have never needed it.
Back to Zeros: I have been riding Zero motorcycles for 9 years, none with traction control and only my current Zero had ABS. During that time I have only spun the rear wheel once and that was a couple of years ago, was while leaned over on a sharp curve of a freeway on-ramp during damp conditions. The rear wheel spun up instantly, the rear of the bike shook violently and weaved from side to side for about a second. But I was able to recover quickly by shutting down the throttle until traction was regained. That lesson from the School of Hard Knocks, taught me a that you do have to be careful with the throttle while riding in possibly slippery traction conditions, especially when not completely upright. I have always thought that riding motorcycles required a lot of skill and experience to do it safely and that goes double when riding in traffic.
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Sorry you had a wreck SgtMickle but I've got about 60k miles on two DS style Zeros and only a pile of sand from a washed out dirt road on the pavement and wet smooth concrete are the only two times I've ever had wheel spin. Release the throttle and your fine.
Never wrecked and never even laid either one down. Five years ago and new to riding motorcycles.
I'd say a dual sport tire is of course far less likely to spin up in the first place so that might be a recommended option for a new rider.
I've found an electric throttle to be an amazing level of speed control once you get used to it.
And until someone gets used to it stay in ECO mode and ride like it's more important to stay out of the hospital than prove what a badass rider they are. They should be fine.
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The arguments against TC are very much like the arguments against ABS... that is, bullshit. All riders begin learning somewhere and continue learning throughout their riding careers and there is no reasonable argument to say that it is fine for your first mistake operating a control to make the bike accelerate also be the control that makes it crash without warning the first time you try it. It is backward, outdated thinking. These days engineers understand that we make things safe to use because they were not safe in the first place. Given that the technology here is - for once - easily implemented at almost no cost (there is already an ABS sensor so no extra hardware is required, only software development), there aren't really any excuses.
Cas :)
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I'm convinced they're only dangerous to gas-bike riders with decades under their belt, as they're the only ones I hear of ever doing this.
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^^^^^^^^^^^ This (to an extent)
I think that attributed to my 3 extreme rear end step out incidents, (as well as tire profile & in one incidence temperature).
On an ICE bike you “pin the throttle” & then back down as the engine “spools up” whereas on an BEV bike you incrementally ratchet up the power to the max needed for the given condition.
It takes some time to reprogram the mind from ICE to BEV.
Yes, traction control would be beneficial during that learning curve as well as a nice safety afterwards.
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Traction Control and ABS aren't perfect, but they're a buddy system with your riding. They won't make you a safe rider if you weren't. But they'll help a safer rider ride to the best of their ability.
-Crissa
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I think the reason that I have never needed any riding aids is because I started riding on a 5 hp scooter, slowly moving upward in power and torque each year or two, riding motorcycles that had poor brakes and worse handling. So I learned to judge the pavement conditions and riding environment over many years and have always been very careful as I ride. Until recently none of my motorcycles would spin their wheels under anything but icy conditions and I have always been careful about braking and keeping my distance from other vehicles. Right now I have two bikes with ABS and one with traction control. My other 4 motorcycles have no riding aids. Since I switch back and forth between my motorcycles, I fear getting into the habit of expecting these aids to save me in an emergency situation, therefore I ride as if they don't exist.
I might add that I have had two motorcycle accidents during 800K miles of riding. The first one was in 1967 when I was riding up to the Panama Canal locks on my 120cc Suzuki when its front wheel fell into the gap between the train tracks and the pavement. The tracks were parallel with the direction of the roadway. That resulted in a cut forearm. The other time was around a downhill hairpin turn while riding my BMW K100RS at about 10mph and hit a patch of oil on the turn, resulting in both wheels sliding out from under me. The bike fell over on its side and resulted in $4,700 in damage, fortunately mostly paid by insurance. That accident resulted in a cracked collarbone and a trip to the emergency room for a few hours. I was back riding within two weeks. I am now very careful when crossing RR tracks that are not at an angle to the roadway and when going around downhill hairpin turns.
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The arguments against TC are very much like the arguments against ABS... that is, bullshit. All riders begin learning somewhere and continue learning throughout their riding careers and there is no reasonable argument to say that it is fine for your first mistake operating a control to make the bike accelerate also be the control that makes it crash without warning the first time you try it. It is backward, outdated thinking. These days engineers understand that we make things safe to use because they were not safe in the first place. Given that the technology here is - for once - easily implemented at almost no cost (there is already an ABS sensor so no extra hardware is required, only software development), there aren't really any excuses.
Cas :)
I'm not arguing against TC as a whole I'm stating once again the idea of an electric vehicle being a "death trap" because it has more torque is wrong. It just takes different riding habits. Like ESokoloff said a gas engine has a delay from throttle to engine spin up to wheel spin up. Electric doesn't.
I didn't start riding till my late 30s so I should have been sucked into that "death trap" if it were so unavoidably dangerous. But it's not.
Keep the bike in ECO. Learn how it feels at slow speeds on empty back roads and a new rider should be fine.
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All bikes are death traps of course :P but the Zeros are particularly unfriendly to beginners (and even experienced riders... and it's not about "instant torque" either, it's about torque pulses, or the lack thereof). Because of the unique traction characteristics of electric motors they really need TC to prevent even the most very experienced rider from instantly binning it on just tiny patches of reduced grip.
Cas :)
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Zeros are not unfriendly to beginners.
There isn't a more friendly bike. It has exactly the torque you want it to have. It has exactly the top speed you want it to have. It never stalls. It doesn't jitter. It doesn't make distracting noises or have complex starting or fueling processes. It moves exactly as you tell it to, so the learning curve is easier.
And a beginner on an electric would never do the stupid things a confident ICE rider would do like cranking on the throttle in a corner.
-Crissa
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I agree, they're far more intuitive and precise. The one thing gas bikes have going for them is they're more forgiving to mistakes, in the sense that they won't send you flying as easily if you're sloppy with the throttle input. Their vagueness and delayed reaction to inputs end up being a good thing (at least in terms of saving newbies). It would be kind of nice if Zero added an adjustable throttle delay or ramp up so the torque builds more gradually to the desired level. My little 1kW dirt bike has a pot to adjust it (although with so little power it's not really needed).
Just like how poor-man's traction control would limit the wheel acceleration to the physical maximum rate (because any faster means the tyre has lost traction) there's also no real reason why you'd want to go from 10% to 100% torque in under a second.
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Why add the delay and teach people to be sloppy when they can just choose to ride with low torque and slowly add what they need as they learn?
-Crissa
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Because of the same problem that people have with video games: you cannot choose your "difficulty" in advance because you do not have any idea of what "difficulty" means in the context of the game. In videogames you choose "normal" difficulty, you start off just fine and then get to a boss and get killed over and over, and like as not ragequit. In motorbikes you select "street", start off just fine, then discover that the difference between 23 degrees of throttle and 23.2 degrees of throttle is a highside on the first wet corner where you discover this limit, smash the bike to bits and break your tibia in 3 places. Not a fun game at all. By comparison ICE bikes have varying degrees of friendliness depending on their engine configuration (if you want something you just can't highside ride a single) and people would routinely crash multis spectacularly as they started making insane power until electronics has come along to tame it all down again.
All of this is just as pertinent to ABS. You can brake >this< hard! ... until you can't, because you don't actually know where that limit is until you cross it, and even if you did know where the limit was, it changes drastically all the time according to many different factors, so you lose the front, and kill yourself. Great fun I'm sure.
Cas :)
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It would be kind of nice if Zero added an adjustable throttle delay or ramp up so the torque builds more gradually to the desired level. My little 1kW dirt bike has a pot to adjust it (although with so little power it's not really needed).
Just like how poor-man's traction control would limit the wheel acceleration to the physical maximum rate (because any faster means the tyre has lost traction) there's also no real reason why you'd want to go from 10% to 100% torque in under a second.
I agree with this, and came to write the same thing.
Zero motorcycles are half computers anyway so it would nice if Zero could add this, if possible. There is no frictionless road where a rear tire would suddenly need to jump to 100%.
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All bikes are death traps of course :P but the Zeros are particularly unfriendly to beginners (and even experienced riders... and it's not about "instant torque" either, it's about torque pulses, or the lack thereof). Because of the unique traction characteristics of electric motors they really need TC to prevent even the most very experienced rider from instantly binning it on just tiny patches of reduced grip.
Cas :)
My thought is that the flywheel effect of power train inertia of ICE motorcycles helps a lot when encountering a loose surface. The tire will not spin up as rapidly as on a vehicle like the Zero, which has no flywheel, or all of the other parts between the piston and the rear wheel that creates inertia and would slow down an instant response to traction loss. I notice that when riding my 390 KTM Duke, which has almost no power train inertial (and fortunately little low speed torque, too) vs my Royal Enfield single that has pretty decent torque, but a lot of flywheel effect. The hard skinny tires on that bike never seem to spin up unexpectedly when they hit a slippery patch of roadway.
But I certainly will agree that if you have a lot of experience riding ICE, you definitely need to be careful when riding a model like the Zero SR versions that can pump out a lot of torque to the rear wheel instantly. It might be a good idea to keep the bike in eco mode unless the pavement is dry and you have your wits about you and really need the extra torque.
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Motorcycles lack of 4 wheels make them all death traps! They don't have seatbelts or rollcages either!
My zero was my first bike and I never had a loss of traction. You have a throttle that controls torque. If you do literally any motorcycle training or even just reading on the subject, you should know how important throttle control is. If you did even the bare minimum of research on a zero before riding it than you understand that there's no gears and the throttle controls power all the way up to the top end, and there's no clutch to disengage that power.
Traction control is a nice safety feature, to cover for user error or unanticipated conditions. But to say the zero is unsafe for not having it, to me, demonstrates a lack of understanding of the bike, and lack of control as a rider.
Sorry you fell and got injured, glad you're OK now. But by your own description you pinned your brand new, high torque, no TC bike in sport mode while you still had very little experience with it. I'm sorry, but that's not an example of a dangerous bike, that's an example of someone who doesn't have respect for the bike they are riding.
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How would he know to have that respect though when the other 99 times he did it, it just whooshed forward? It's the one time where there's a tiny greasy spot. And when he says pinned I bet he didn't even get over half throttle either - most people who think they're giving it full throttle turn out to barely manage 50% (datalogged on a racetrack). The difference between instantly losing 100% traction and having perfect traction with electric motors is a hair's breadth of throttle and there's some amusing footage of professional Moto E riders on Energicas discovering what happens when they open the throttle just too fast.
There's no fun in second guessing traction when the result is instant crashing. With ICE we get controlled slides. With EVs we get instant total loss of traction.
It might not be very manly or alpha male to say I want a safety net but tbh I give no craps. If my daughter were to announce she was going to buy her first bike tomorrow, I would not want her on an older Zero, in the same way I wouldn't want her on a bike without ABS. I'm alive after 30 years riding mostly through luck so far, as the times I've lost traction on the bigger bikes I used to ride I saved it, but not through skill or knowing what to do, just through luck and the reasonably forgiving nature of the engines. Nowadays I've got TC and ABS on my bikes and it's just a great relief to know I don't have to treat the throttle as a device that can kill me without warning if you turn it round to read the warning label underneat, but a device that makes the bike go faster, just as the lever now makes the bike stop these days instead of occasionally simply throwing you off like they used to.
Cas :)
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How would he know to have that respect though when the other 99 times he did it, it just whooshed forward?
If it's a 2021 model, which wasn't even revealed until mid-OCT this year, and they've already crashed it, had it repaired, and are back on the bike, they didn't have 99 other times to compare it to. This isn't "I rode this bike for a year of being predictable and it suddenly betrayed me" this is "I bought a brand new bike I don't understand and tried to immediately take it to the limit, and it bit me!" We don't even know if their tires were broken in!
My point is they pinned a bike they did not understand the dynamics of and was basically unfamiliar with.
I don't disagree with any of your points about how traction control is good. It is! More safety features are good! But buying a bike with an entirely different drivetrain than the bikes your used to, with a throttle that behaves differently than an ICE bike, with lots of torque, and no traction control, and then yanking on the throttle like you're trying to reach a redline is a recipe for disaster and a showing of complete lack of respect of the bike and its power.
Comparing street riding habits to professional moto-e riders who are by definition riding to the limits of the bike, in full gear, on a track, is irrelevant.
Fact of the matter is that the SR has a lot of torque and no TC. If you know that, and understand how traction works, you should be extremely careful with your throttle and learning the limits of the bike. In the simplest terms you have to retrain your brain to transfer all the nuance you had with your clutch + throttle + shifter into just throttle control.
If that's too much responsibility for you, yeah you probably shouldn't be buying a bike without TC. Good news, the SR/S and SR/F have it, so if it's important to you Zero has options for you. Energicas have TC as well.
I don't think its controversial to say you should understand the bike you're buying before you buy it. If TC is important to you, get a bike with it. If it isn't, and you get a bike without TC, you need to both have the skill to ride without TC and be prepared for the risk in the moments where your skill isn't enough. It's all managing knowledge, skill, and risk, like anything in motorcycling. You don't get onto two wheels without doing that, and you have to own the choices you make in that space.
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By comparison ICE bikes have varying degrees of friendliness ...
This is inane and untrue. Zeros do exactly what you tell them to do. The ICE bike doesn't have a friendliness - you don't know where that torque curve is until you've ridden it. You don't know until you pull the throttle while going 60 on the freeway that the weight of your buddy on the back is going to push it to lift the front off the ground, either.
The Zero does exactly what you tell it to. And you're used to a bike that doesn't do what you tell it... So you're okay with hitting that power band in the middle of a corner and sliding out? Or stalling out with a slight misapplication of the clutch... But not okay with your misapplication of throttle doing exactly what the throttle should do?
With a Zero you can always set the torque where you want it. You can raise it slightly for your skill, lower it for the terrain, and you don't have to ever worry about it catching unevenly.
-Crissa
...And I have slid out the back of my bike, lots of times. Never when it wasn't my fault, or some roadway hazard. It does what I tell it. There's a reason I don't ride my spouse's Ducati outside of parking lot practice: Because I know it will break loose and have uneven power bands and is way above my skill level. It's no different than cranking the torque on my bike to full, or jumping on an SR. Experienced riders forget to respect their bikes.
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By comparison ICE bikes have varying degrees of friendliness ...
The Zero does exactly what you tell it to. And you're used to a bike that doesn't do what you tell it... So you're okay with hitting that power band in the middle of a corner and sliding out? Or stalling out with a slight misapplication of the clutch... But not okay with your misapplication of throttle doing exactly what the throttle should do?
This is exactly it! The throttle does exactly to tell it to do, if you gave it a bad input, that is nobodies fault but your own.
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There is no frictionless road where a rear tire would suddenly need to jump to 100%.
But there can be jumps!
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You cannot teach 70 million people not to be stupid. So why blame Zero for people who cannot ride?
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By comparison ICE bikes have varying degrees of friendliness ...
The Zero does exactly what you tell it to. And you're used to a bike that doesn't do what you tell it... So you're okay with hitting that power band in the middle of a corner and sliding out? Or stalling out with a slight misapplication of the clutch... But not okay with your misapplication of throttle doing exactly what the throttle should do?
This is exactly it! The throttle does exactly to tell it to do, if you gave it a bad input, that is nobodies fault but your own.
No, this is a useless fallacy of an argument. The problem is not what the throttle does, it is what the tyres do in reaction to the throttle. The throttle appears to do the same thing on the 70bhp Zero DSR and the 70bhp Duke 690 but the wheels are doing something very, very different.
I imagine most of the time when people are opening the throttle they are expecting the tyres to do what they did last time, that is, grip the road, and accelerate. They do not always do this. There are a huge number of variables, some of which will be in your perception, some of which won't, some of which may be in your perception but "just this one time you under/overestimated it".
Different engine torque characteristics will give different results over different grip situations and different margins for error. The very best configuration is a single cylinder ICE engine, which has a margin of error and controllability so wide that almost anyone can act like a tit and enjoy themselves, as it loses traction for only some small percentage of the rolling distance of the tyre on each bang (despite making hugely more instantaneous torque than the EV - something like 800lb-ft), and with as such has such a degree of controllability you can entertain yourself for hours experimenting with how much you want it to slide.
The very worst configuration is the electric motor, which loses traction totally, completely, and instantly, on a knife edge, and can lose it at any point with equal probability on the circumference of the tyre as it rolls, and then will spin up instantly so as to not regain it until the rider is on their ear or possibly worse, snaps it shut causing it to similarly instantly regain traction and introduce the hapless rider to the high side. You can actually apply considerably greater acceleration on the 690 round a corner than the DSR because it maintains grip despite accelerating harder, and because you just don't have to worry about suddenly losing it. It really isn't fun trying to guess where the limit is when it's 0.1 degree of throttle and you're off.
Rather than glossing over this minor detail I am a bit surprised you're not strongly advocating for TC to be mandatory on EV bikes, in the same way that ABS is.
Cas :)
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After 12,000 miles of an 81.1 mile loop on my Zero SR I stopped riding it due to it wanting to highside the rider when the rear is unweighted due to a hard bump or pothole, traction is lessened due to surface change like gravel, bike is transitioned from side to side, and throttle roll-on occurs. To mitigate this I weigh the outer peg too and squeeze the tank to ride it 100% grip, in Eco mode, which makes for an overly tense ride. The poor ergos mean when the rear is bucking around there's not a tank to reassuringly squeeze to reduce bar input and stabilize the bike.
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I wouldn't say the throttles do the same thing. The throttle on a Zero directly controls how much torque is generated (wheel or motor, doesn't matter). The throttle on a gas bike can change the torque but only indirectly. The only thing it does control directly is the amount of air and fuel put into the combustion chamber and the result of that is wildly variable. I like to think of it more like a suggestion, or tugging on the reigns of a horse (or whatever it is horse riders do). Perhaps the best analogy for twisting the throttle on an electric bike would be pressing down on the pedals of a bicycle, you have direct control over the amount and duration of force and nothing more or less.
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I'd say the throttle on an EV is a bit like what you might expect if you have a V12 engine in your bike.
This resource is endlessly useful when trying to talk about all this stuff:
http://www.epi-eng.com/piston_engine_technology/torsional_excitation_from_piston_engines.htm
Cas :)
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Nice write up about the tire and spin up. There is compression braking before the power pulse and a flywheel. Coushioned drive line most likely as well. It seems the KTM 690 has traction control from my internet search.
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I wouldn't say the throttles do the same thing. The throttle on a Zero directly controls how much torque is generated (wheel or motor, doesn't matter). The throttle on a gas bike can change the torque but only indirectly. The only thing it does control directly is the amount of air and fuel put into the combustion chamber and the result of that is wildly variable. I like to think of it more like a suggestion, or tugging on the reigns of a horse (or whatever it is horse riders do). Perhaps the best analogy for twisting the throttle on an electric bike would be pressing down on the pedals of a bicycle, you have direct control over the amount and duration of force and nothing more or less.
Have you experimented going from flat to hill and not changing throttle twist position? It might behave like cruise control instead of constant torque. I do not have a Zero but was quite surprised that my KTM held a steady 35 mph. At 5 mph different.
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By comparison ICE bikes have varying degrees of friendliness ...
The Zero does exactly what you tell it to. And you're used to a bike that doesn't do what you tell it... So you're okay with hitting that power band in the middle of a corner and sliding out? Or stalling out with a slight misapplication of the clutch... But not okay with your misapplication of throttle doing exactly what the throttle should do?
This is exactly it! The throttle does exactly to tell it to do, if you gave it a bad input, that is nobodies fault but your own.
No, this is a useless fallacy of an argument. The problem is not what the throttle does, it is what the tyres do in reaction to the throttle. The throttle appears to do the same thing on the 70bhp Zero DSR and the 70bhp Duke 690 but the wheels are doing something very, very different.
I imagine most of the time when people are opening the throttle they are expecting the tyres to do what they did last time, that is, grip the road, and accelerate. They do not always do this. There are a huge number of variables, some of which will be in your perception, some of which won't, some of which may be in your perception but "just this one time you under/overestimated it".
Different engine torque characteristics will give different results over different grip situations and different margins for error. The very best configuration is a single cylinder ICE engine, which has a margin of error and controllability so wide that almost anyone can act like a tit and enjoy themselves, as it loses traction for only some small percentage of the rolling distance of the tyre on each bang (despite making hugely more instantaneous torque than the EV - something like 800lb-ft), and with as such has such a degree of controllability you can entertain yourself for hours experimenting with how much you want it to slide.
The very worst configuration is the electric motor, which loses traction totally, completely, and instantly, on a knife edge, and can lose it at any point with equal probability on the circumference of the tyre as it rolls, and then will spin up instantly so as to not regain it until the rider is on their ear or possibly worse, snaps it shut causing it to similarly instantly regain traction and introduce the hapless rider to the high side. You can actually apply considerably greater acceleration on the 690 round a corner than the DSR because it maintains grip despite accelerating harder, and because you just don't have to worry about suddenly losing it. It really isn't fun trying to guess where the limit is when it's 0.1 degree of throttle and you're off.
Rather than glossing over this minor detail I am a bit surprised you're not strongly advocating for TC to be mandatory on EV bikes, in the same way that ABS is.
Cas :)
The throttle does the same thing every time. It puts torque to the rear wheel exactly how you tell it to.
Your wheel does not, and that is true no matter what the drivetrain is. Like you said there are a number of variables that effect your grip, from the tread on your tire to the road surface, condensation, temperature, weight on the bike, etc.
But you as a rider need to understand these variables and ride accordingly. The fact that your throttle is always going to give the same power to the rear wheel is actually empowering in that it takes several of those variables away that are present in the ICE drivetrain.
If you as the rider do not understand these variables and the risks involved when opening the throttle, you only have yourself to blame.
All you need is the self control to not tug on the throttle! You keep talking about being at the edge of traction where 0.1 degrees of the throttle will cause a crash, if that is the case then you as the rider are riding way too close to the threshold. We're talking about public roads here, not the race track. If you're close enough to where 0.1 degrees is going to lose you traction, that is your own fault for riding way too aggressively for current conditions. You know the electric motor has torque across the rpm range, you know the throttle is sensitive and directly controls that torque. You shouldn't be "guessing" how much you can tug on it like you're playing a video game.
I'm in the states, ABS isn't mandated at all. But it's a good feature and I do think it's good that it's more and more common. TC is a good feature too and I do think the more bikes that have it the better. Do not mistake me advocating for riders understanding their own machine and riding within the machine and the riders limits as a dismissal of good safety tech.
But safety is a relative thing, we all take different risks. We can argue about what the right safety choices are until we are blue in the face, but the bottom line is that you are taking more of a risk getting on 2 wheels than someone who rides in a car, who is taking more risk than someone who takes public transit. People ride with no gear, sometimes even no helmets. Others are ATGATT, others go even further and wear the new airbag vests on their motorcycles.
We all choose our own level of safety and risk. All I'm saying is that if you ride an electric motorcycle without TC, and then blame the lack of TC on your full-throttle crash, you are doing yourself and your bike a disservice. Know what you ride, know the risks, and own your decisions.
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ICE bikes are death traps, and to see people advocating for lossy, poor-response, random-torque like gas bikes put out is baffling.
If you need to cling to the bike to ride it... What are you, a newbie like me? Yeesh.
-Crissa
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So is there any organization out there that actually keeps track of the number of deaths related to lack of traction control and if so how do they compare to deaths attributed to alcohol use by riders and distracted drivers?
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Yes, at least the UK keeps a fairly close eye on it, and KSIs from loss of traction are no larger than KSIs from loss of control after braking before ABS, but the trick here is to be reactive and progressive thinking, not wait 20 years and then look at the statistics, throw hands in the air and say "oh EVs without TC are dangerous, who knew!" It was noted 30 years ago that loss of control during braking was causing accidents and fatalities (even amongst very experienced riders) and rather than saying "it's your fault, you're entirely to blame" the powers that be realised they could actually fix it with technology and legislation, and lo and behold, KSI statistics continue to fall because large classes of accidents just don't happen any more.
We can see there's a problem here, and the solution is surprisingly simple to implement - the tech is already there, it just needs legislative backing, just like ABS got.
Cas :)
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If you want TC you can buy a modern sportbike that offers that feature. If you want TC on a electric bike you're welcome to write manufacturers and request it. The sensor technology may be there but I really don't think implementation is as straightforward as some of you may think. And TC is no guarantee you won't slide out on a slippery surface, just as ABS is no guarantee you'll be able to stop in time. These technologies don't improve traction. Or, you can stop treating public roads as a racetrack and slow down a bit, especially in turns.
Modern tires are incredibly good but if we don't understand basic risks of sharing roadways with other vehicles, all the technology in the world can't help. Maybe I'm getting older but there's an awful lot more people in the world now than there was when I started riding and an awful lot more vehicles. Roads are in worse shape and drivers are more inattentive. Want to go fast? Pick your circumstances. Want to go faster? Head to the track.
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I wouldn't say the throttles do the same thing. The throttle on a Zero directly controls how much torque is generated (wheel or motor, doesn't matter). The throttle on a gas bike can change the torque but only indirectly. The only thing it does control directly is the amount of air and fuel put into the combustion chamber and the result of that is wildly variable. I like to think of it more like a suggestion, or tugging on the reigns of a horse (or whatever it is horse riders do). Perhaps the best analogy for twisting the throttle on an electric bike would be pressing down on the pedals of a bicycle, you have direct control over the amount and duration of force and nothing more or less.
Have you experimented going from flat to hill and not changing throttle twist position? It might behave like cruise control instead of constant torque. I do not have a Zero but was quite surprised that my KTM held a steady 35 mph. At 5 mph different.
The speed should decrease as the Zero goes up hill and increase coming down, compared to riding on flat ground. The throttle position has a direct relation to the torque output, 50% throttle is 50% of maximum torque. What speed that percentage of torque results in depends on a few factors including the gradient of the road and wind resistance.
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We can see there's a problem here, and the solution is surprisingly simple to implement - the tech is already there, it just needs legislative backing, just like ABS got.
Cas :)
If we legislated away everything that included risk, all motorcycles would be illegal. There has to be a balance between common sense safety legislation and personal choice and responsibility.
Again, we can advocate for TC as a good safety feature while still advocating for responsible riders.
IIRC TC is harder to implement than ABS at this point. It's true that the tech exists and sensors are cheap, but it requires tuning to the individual bike and it is supposedly harder to implement on EV's because of the same torque characteristics we're talking about. This adds cost.
It's not a coincidence that cheaper, entry to mid level bikes tend to not have TC while higher end bikes do, it costs money! If we banned all non TC E-motos right now, there wouldn't be a single option under $20k. In the US there is only 1 ICE bike under 10K that has TC. Mandating TC at this point would price almost all new riders and lower income people out of the already struggling market.
ABS is more widely available on lower end bikes, partially because of EU laws, but mainly because it's much cheaper to implement and easier to transfer from bike to bike. In the US ABS can commonly found as a $500 option. The same is simply not true for TC, because it's much more complicated to implement than your dismissive "just software" comments give credit to.
Some new bikes have cornering ABS, should we ban all the bikes with plain-ol ABS?
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The 2020 KTM 390 Adventure has TC, but many people turn it off because it somehow cuts the bike's performance both on the highway and off road when the system is activated, according to a fellow that I know who used to have one of those bikes and recently sold it as it wasn't meeting his expectations.
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Bit of a gimmick on a single really. (Yes, my 690 has it, but as I say... gimmick)
Cas :)
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The 2020 KTM 390 Adventure has TC, but many people turn it off because it somehow cuts the bike's performance both on the highway and off road when the system is activated, according to a fellow that I know who used to have one of those bikes and recently sold it as it wasn't meeting his expectations.
This is exactly why mandating TC isn't going to automatically make us all safer.
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I think the fact it doesn't go as fast as he hoped when TC is on is maybe orthogonal to the discussion. (And also, bullshit, what is he expecting from a 390)
People moan about ABS lengthening stopping distances. It does. A very good rider can outperform it by a couple of metres. Sometimes. When it's warm and dry. After a few practice runs. For the rest of us, we're just glad that all bikes now all stop in 52 metres from 70mph, whether it's wet or not, whether the tyres are hot or not, whether the road is hot or not, whether we've panicked and grabbed the brake instead of squeezing, whether we went over a patch of sand or a bit of ice or a bit of diesel, without us falling off. Every single time.
Cas :)
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Rider error on my end, coming from inexperience on the bike and not-so-good judgement, was definitely a big part of why I crashed. I'm not trying to deny this, nor am I trying to shift blame from myself to the bike.
I am trying to make the point that what Zero did - having an electric bike this powerful without traction control, or any type of software assistance to deliver torque more safely on full throttle - is particularly dangerous. More so than people might think. I think that this is an important conversation to have, and important for people riding / considering electric bikes to be well aware of, as unfortunately I wasn't.
Sure I'm exaggerating when I call zeroes "death traps." But it does make sense to say that TC (or some degree of software assistance on the throttle) on high-torque electric bikes is especially important, and more so than gas bikes because of the nature of these vehicles. Rear-wheel slides from throttle is a common cause of crashes on electric as has been pointed out, and TC would no doubt save many riders of these bikes from crashes, injury, and death.
Like I said - I wasn't even cornering when I crashed, and the pavement was dry and seemingly free of debris. It simply happened because I asked for full throttle. It just doesn't seem to make sense to me to have a bike that can't handle the power of its own throttle.
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ABS outperforms nearly all riders on pavement and always does on wet pavement.
It only doesn't when on something like gravel. Because ABS doesn't know what kind of surface you're on, if it did, it could outperform humans even then.
-Crissa
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Rider error on my end, coming from inexperience on the bike and not-so-good judgement, was definitely a big part of why I crashed. I'm not trying to deny this, nor am I trying to shift blame from myself to the bike.
I am trying to make the point that what Zero did - having an electric bike this powerful without traction control, or any type of software assistance to deliver torque more safely on full throttle - is particularly dangerous. More so than people might think. I think that this is an important conversation to have, and important for people riding / considering electric bikes to be well aware of, as unfortunately I wasn't.
Sure I'm exaggerating when I call zeroes "death traps." But it does make sense to say that TC (or some degree of software assistance on the throttle) on high-torque electric bikes is especially important, and more so than gas bikes because of the nature of these vehicles. Rear-wheel slides from throttle is a common cause of crashes on electric as has been pointed out, and TC would no doubt save many riders of these bikes from crashes, injury, and death.
Like I said - I wasn't even cornering when I crashed, and the pavement was dry and seemingly free of debris. It simply happened because I asked for full throttle. It just doesn't seem to make sense to me to have a bike that can't handle the power of its own throttle.
It's fair to mention that having a bike with high torque across the RPM range, a direct throttle, and no TC is going to have more risk of a tire braking loose than other bikes, and this is a danger to be aware of when riding. To me this doesn't make the bike more inherantly dangerous, but it does make the action of yanking on the throttle in the way you did more dangerous, and riders should understand that.
Riders should know that the zero's throttle is torque-control, not simply speed control.
The bike can handle full throttle, but it needs to be applied with finesse and understanding how it works. It's not building power when you pull the throttle like an ICE bike, the power is there. So you asked it to apply full torque immediately, it listened, and you went down. The bike just listens to your input, and you assumed either through ignorance of how the zero throttle works, or from experience with ice bikes, or both, that it would behave differently than it does.
The bike listening to the riders input is not, IMO, a glaring safety issue as much as the owner not understanding how the bike works, and this is where to me things get trickier. Zero should explicitly state how their throttle works, and the dealer should warn you as well. But of course, they're both in the business of selling bikes, we all know that bikes are dangerous, so they're not incentivized to focus on the dangers of their products.
This is where I do take issue with the marketing material for how easy to ride e-motos are. "Just twist and go!" is technically true but also an inadequate amount of information. If a sales rep was to explain to you the nuances of the way a zero's throttle differs from your ice bike, you would have had more correct assumptions about how your bike works and potentially not put yourself in the same situation.
There is definitely a big gulf of knowledge when it comes to your average rider and how e-motos work. I know plenty of people that will hapilly tell you about different engine types and their characteristics but will look at you with a deer-in-the-headlights look if you say something like PWM. We could be better at describing these differences so people understood their e-motos more as the machine they are and less of a magic box where you just twist the throttle to go.
But in the end to me it still comes down to understanding the bike and the power it has. For the 5-6 examples here of people breaking rear traction with their zero, there are hundreds of stories of inexperienced riders on powerful ICE bikes giving too much throttle and paying the price for it. The details are different but the story is the same. If you get on a powerful bike you do not have experience with and give it the wrong input, it will bite you.
ABS outperforms nearly all riders on pavement and always does on wet pavement.
It only doesn't when on something like gravel. Because ABS doesn't know what kind of surface you're on, if it did, it could outperform humans even then.
-Crissa
I wonder what kind of sensors and software it would take to make and ABS system that knows the type of surface it's on. It would have to be able to either use simpler sensors and lots of training data to know what a surface looks like or have some more advanced sensors that can figure out how tough the material it is and how loose the particles are. But then it would also have to work even if the sensors are obscured by mud or grime. Quite the engineering challenge.
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Right now, ABS for off-road does things like locking back wheels but not front, having certain speeds or slip angles, or checks against multiple wheels. Which bikes don't have alot of wheels to test against.
But there have been demos of automated driving systems (visual) identifying the surface and changing how they apply a brake when you ask for more than the wheels can give. Tesla has suggested that for their Cybertruck, the FSD system will do this; taking advantage of computer control over shock stiffness, ride height, and brakes in an advanced way. They haven't demonstrated it yet, but had tried a GPS based system in the Model S which was pretty good. Well, until they had a couple that people drove over debris on the freeway and sliced open the car...
Right now, a rider or driver's big advantage is that you can visually identify hazards like surface, inclines, debris; and the computer systems can only feel along blindly. But they can feel along blindly better than even the best rider. So it's how do we mix the two tools to make both rider and bike safer.
But that doesn't make what came before a death trap. If I see puddles in the corner, I can definitely flick the mode to Eco or Rain and tell the bike to go easier on the torque. Or if I'm getting on a freeway on-ramp, I can flick it to Sport. As a rider, I can and should do these things.
That's why the first thing I always tell people about my bike is that it has that ability to turn the torque down so I have exactly the amount of power I need for my skill or the road surface. With an ICE bike, if you choose the wrong gear, you'd have the same result. Plus the hazard of downshift shudder! You can start from a stop in second gear, you know, if you really want less torque.
-Crissa
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I think that was an excellent analysis, Caza. :)
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I am trying to make the point that what Zero did - having an electric bike this powerful without traction control, or any type of software assistance to deliver torque more safely on full throttle - is particularly dangerous. More so than people might think. I think that this is an important conversation to have, and important for people riding / considering electric bikes to be well aware of, as unfortunately I wasn't.
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It would be nice to have this thread end up as a “Sticky” in a “New Rider: Read This First” section.
Also it would be nice if Zero & others included such stern warnings in their literature on each models but then I’m sure that opens up a legal can of worms.
Regarding your accident, I’m curious if the tires were cold?
I believe that contributed to one of my rear tire step out incidents.
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Regarding your accident, I’m curious if the tires were cold?
I believe that contributed to one of my rear tire step out incidents.
Good question. It was a warm day and I was riding around for some time that day before the slip, so the tires must've been pretty warm. However it was a *brand* new bike at the time, so the tires might not have been broken in yet.