Street-Legal ebikes are underpowered
electricbike-blog.com
electricbike-blog.com
If a collision between an unprotected bicyclist and a stationary object is similar to that between a car and a pedestrian, the chance of death in a 15mph (25kph) collision is around 5% and the chance of non-minor injury is 10%. In a 50kph collision, that jumps up to a 50% chance of death and 95% chance of non-minor injury.
http://www.safespeed.org.uk/killspeed.html
So sure, build your 30mph bike if you want to, but understand that it's no longer a bike, it's a motor vehicle, and should be restricted to licensed adults and should not be used on bike paths and the rider should probably be wearing a motorcycle-style helmet. I know there's some debate on the effectiveness of bicycle helmets at preventing injury in the low-speed accidents cyclists are usually in, but for motorcyclists, the benefits are more clear -- a 37% reduction in deaths and 67% reduction in brain injuries.
http://www.iihs.org/iihs/topics/t/motorcycles/fatalityfacts/...
Oh, and make sure that your brakes are able to stop your 1000W+ motor if the throttle gets stuck wide open.
This cannot be stressed enough. The amount of new builds on ebike forums where people are building essentially electric motorcycles on bicycle frames with no upgrades to non-drivetrain components is scary.
Even with my 500W motor (illegal here, but would be legal in the states, and puny compared to the stuff the article's author is talking about), I found myself wishing the brakes were more responsive. I upgraded the brake pads which made the ratio of stopping power to acceleration acceptable.
Then after a year of using that, the aluminum stirrup that the brake noodle slides into bent enough for the noodle to pop out, putting my front brake out of service. This happened while I was applying braking power during a steep downhill descent going 35-40km/h, I lost control and fell off the bike. The stirrup wasn't designed to handle the braking forces I was applying to it with the new brake pads, so over time it bent outwards and eventually gave way.
Don't neglect your brakes! After this I upgraded to mechanical disc brakes.
EDIT: Regarding "if the throttle gets stuck wide open" - if you don't have motor safety cutoffs installed on your brakes, you should do so now. I've had my PAS controller get into a state where it decided to just apply power even with no movement on the pedals. Always have a cutoff switch! If you dislike the chinese ebrakes (and they do suck), there are inline wire sensors you can install to keep your existing brake handles, and it's also fairly simple to modify your existing handles with a reed switch.
Long descents where there is significant energy to recover are not that common for most riders.
It's a different story with a 50 ton train where a 20 KW resistor bank is not a significant amount of weight, but adding a 500W resistor bank to a bike (since you need somewhere for energy to go when the battery is fully charged) is probably not going to be worth the weight and expense.
Plus you need some sort of blending between regenerative and friction braking, so it's yet another thing that needs adjusted and maintained.
The most unusual thing I ever saw in my EV days... We had a full Ford Focus Electric on a chassis dyno to debug some problems. After several hours of tuning and data collection we realized the car needed to be charged to get it back to our own facility. The dyno place had no high power chargers. So we set the dyno somewhere around 40mph, put the car in drive and left it. With no foot on the gas it would do a light regeneration at that speed. The strange part is that we sat around a table to analyze the days data about 5 feet from the car. We're at a table next to a car tied down and going 40mph and its almost dead silent charging via regen. Analysis done, car charged, untie it and off we went ;-)
A bike has very little rolling resistance, nearly all of the energy used to propel the bike on level ground is going toward fighting air resistance. Even on rolling hills, I rarely use my brakes on the downhill, any regen braking used on the downhill is just going to increase the energy needed to go up the next hill. (and due to less than perfect efficiency, you lose energy on both the regen capture and powering the motor again, so it's a big loss).
So yes, you might recover some small amount of energy used to decelerate the bike at a stop sign, it's not going to be significant percentage of the total power requirements, and you're going to be paying a price in dollars, complexity and weight for this feature.
It's firmware limited to 20 mph which _feels_ slow but is probably a sane compromise. We only hit that going down hill, and are far from the fastest cycle; but we average 12-15 mph on mild uphills and flats when conventional cycles usually average a few mph slower.
I love my ebike, it makes a daily commute taking two kids to school then getting on to work feasible, regardless of weather or relative personal energy level.
Hope makes some nice DH brakes: http://www.hopetech.com/product/tech-3-v4/
Avid has the Code: https://dirtmountainbike.com/bike-reviews/brakes-gears/avid-...
And other manufacturers also make calipers with >=4-piston calipers.
Again for rotor size, 160mm is typically standard for XC, road bikes run 140mm usually, some "all mountain" bikes have 180mm fronts, and 200mm is typically seen only on DH/4x/trials/dirt jump bikes but likely what you want for a fast ebike.
All that said, competition-level road bikes generally hold up fine at speeds up to 60mph (and the riders hit those speeds going down hills) and their brakes work fine. You obviously don't just mash them, and the rim surface they're clenching matters a lot, as do the pads, but the tech works well and has worked for the past 100 years. Weight distribution and even application of both brakes help a lot.
For >750W e-bikes that go over 28 mph you'd normally need DH brake tech, 180 rotors at least. Shimano Saint Ice tech is good, Magura brakes are also top notch, even the lower end models. Avid Code looks rather flimsy and advertises low weight. I would avoid any calipers w/o metal bodies as it does not dissipate heat well. The Hope caliper looks especially good - lots if surface, lots of metal. The brakes and the steering are the last things to save weight on.
Yes, V-brakes.
> I wouldn't run anything less than hydrolic disks on something that fast. Preferably dual piston like the ones Sram are making now.
I actually didn't specify anything about the speed of my bike in the post, but mostly I ride below 25km/h. The 35-40km/h quoted was coasting down a steep hill, and I would have gone the same speed without the motor. It's just that the added load caused the V-brake stirrup to bend open over time, and then it finally popped out in that situation.
I think idea that disc brakes, mechanical or hydraulic, are "more powerful" than V-brakes or canti's is a misunderstanding. If you think about it, the absolute limit to a bicycle's braking power is as much force as possible without locking the front wheel and sending the rider over the handlebars. Any bicycle brake can do that, and if it can't it should be returned to the store as defective. The reason I switched to discs was that the whole assembly seemed more solid than V-brakes (no loose coupling like in the harness). The other big reason to switch is the feel of the lever (better control over braking modulation), and needing to put less force on the lever for more braking power, so your hands get tired less.
The main reason I went for mechanical disc brakes vs hydraulics is the ability to service them on long trips. I'm not going to bring tools to bleed the hydraulic system on touring trips.
EDIT: Another reason I picked mechanical is that it's simpler to wire a motor safety shut-off switch to mechanical brakes. For hydraulics you need to do the reed-switch mod I mentioned which is a bit more finicky, or install a hydraulic sensor which requires bleeding the system.
As an aside, it's weird that in the bicycle world we talk about disc brakes vs rim brakes since they are all disc brake systems (in a rim brake, the rim itself takes the place of the rotor). I don't think I've ever seen a bicycle with a drum brake :)
I think the failure mode of cable-operated disk brakes might be better (though I've since ditched the bike, so that's speculation).
If you want moped speed, get a moped. You can't safely upgrade one component; you need to upgrade them all. And it's not just your safety, it's the safety of the public, and they have a right to legislate that you don't drive a dangerous vehicle on the public highway.
Also if he wants to play around and weave in and out of cars at 30 mph+ and he ends up as a road waffle too bad, so sad.
Eh, depends on the location. My sister rode a bike every day for about 4 years (she didn't have a car). She always rode on the sidewalk because she rode at a slower pace, the sidewalks generally didn't have any people on them, and in her neighborhood if you tried to ride in the road you'd get mowed down by vehicles. There's really some places where it makes most sense to ride on the sidewalk even if you aren't supposed to.
Regarding the general question of danger to pedestrians: good urban planning works wonders.
The next step down is electric scooters, which are around $1000-$2000. They aren't pretend bicycles, but are more street-suitable.
Oh come on. Exactly how was that statistic collected? When people have non-fatal accidents they usually don't report it.
In fact, the link you posted above is to a guy complaining that the stats you quoted don't stand up to reason.
Here's another study: https://www.aaafoundation.org/sites/default/files/2011Pedest...
This one shows a fatality rate of 2.3% for speeds from 10.0 – 19.9 mph, and 35% for speeds from 30.0 – 39.9mph. Even though the rate is different, it's still showing over a 10X difference in fatality rates at the higher speeds.
Consider this, at 30mph a cyclists body has to dissipate 4 times more energy than a 15mph cyclist. There's not much in a bike to absorb energy like in a car.
Fortunately, a lot of custom sinusoidal controllers have a voltage gap between 0-1V and 4-5V (or whatever full throttle is for a build) to prevent full throttle or full braking with any electrical component in the case of wiring failure.
In Hawaii, because some people tend to drive too slowly and doing so causes crashes, they post the minimum speed below the limit on a lot of roads. Across the US, it is illegal to go more than 15 below the limit in clear conditions.
Once a cyclist has a motor, it seems they are more likely to 'claim' a lane and then they need to keep up or risk being a roadblock. It's less safe either way, and I'm not sure there is a viable solution. Part of the thrill of cycling in traffic, I guess.
And even if you are doing 35mph, and claiming a lane, you'll still be passed (often unsafely) by cars doing 40, 50mph. (Source: motorcyclist who can't go fast up hills)
I'm also not really sure what he's arguing for. That manufacturers of complete ebikes should just sell bikes that can't be ridden legally on the streets? They'd be sued if they did that. As a DIY builder you can take that chance, as a business selling to the public you can't. If you disagree with the ebike restrictions, you should be focusing your efforts on the politicians and public servants that make those policies.
Also, I'm not sure "ebike" is a good term for what the author is talking about. It's firmly into e-moped territory and possibly an electric motorcycle. Which is not to say that bikes more powerful than the legal limit can't qualify as ebikes, but when you're pushing 2500W through your motor, the addition of pedaling won't even register because it's such a small fraction of the total power, so it's really not a bike.
All that said, the US has it really easy when it comes to ebike regulations. You can go to 750W! That's enough for an e-bike. Over here in europe we're limited to 250W which really is ridiculously small. I have a 500W motor on my bike, putting it firmly into illegal territory but it's still definitely a bike.
He maybe have had a point if he had concentrated on the 25 kph (15.5 mph) speed limit for electric assistance in the EU. That is far too slow.
By the way, technically in the EU there is no power limit. There is a 250W 'continuous' power limit, but 'continuous' is never defined, and Bosch's bikes go up to 500W for at least 10 minutes.
[1] http://www.power2max.de/northamerica/wp-content/uploads/2014...
Really? It makes a lot of sense to me. In The Netherlands e-bikes are used mainly by elderly to stay mobile in the face of a weaker body, and sometimes by commuters riding for longer distances. 25km/h is quite fast for a device with as little protection as a bicycle, and more than fast enough when riding in traffic or in an urban area. If you want to go faster and still be able to avoid traffic, you get a moped with a 45km/h limit (helmet, insurance, and licence required), or get a racing bicycle (and a good condition) for those long stretches of road.
A 25km/h speed limit is probably very reasonable in a dutch city. If I'm riding my bike on a deserted highway in Iceland with 150km between towns, allowing riders to go to 35-40km/h would make ebikes much more practical.
My main problem with the regulations is how they're all based around what a bicycle can do, which restricts development of new, innovative use cases for ebikes. The 250W limit was decided because that's what an average healthy adult can maintain for a decent amount of time. But why should an ebike be limited by that? I can get a cargo ebike that can carry 200kg of cargo, but that 250W motor isn't going to get it up the hill. A speed limit on that kind of vehicle makes perfect sense, but a 250W power limit seems much too restrictive.
If you have to travel long distances, an eBike is probably not the right vehicle unless you're just out for the ride to enjoy the scenery, and if that's the case, is 25km/hr really a problem?
Because I want to? Riding an ebike is a very different experience to riding a motorcycle (I have my motorcycle license and have owned a motorcycle in the past). You see more of the land, but sometimes you want to go a bit faster than 25km/h without going 100km/h. This is sort of like demanding someone justify their use of a car since we have public transit.
Besides, the law shouldn't be based on "why would you?", it should be based on solid safety arguments. I can see the validity of those within cities, but not so much in more rural areas.
You have a very specific use case, if you can buy a bike that goes 40km/hr on a deserted road, you'll also be able to use that same 40km/hr bike on crowded urban bike paths.
If you want a vehicle that goes faster than a bike, there are plenty of options. The faster vehicles abide by more stringent safety standards and have restrictions on where they can ride (i.e. you can't ride a motorcycle on a bike path, but depending on where you are, you might be able to ride a speed restricted moped there).
Right, just like people who buy Teslas that can go 200+km/h can take those cars to the residential street with 15km/h limit and children playing in the street. We make laws that apply to the operator of the vehicle, instead of deciding a maximum safe speed for cars of 15km/h and applying a limiter to every car's engine. That's my whole point - the law should apply to how the engine is used, same as most every other class of vehicle out there.
If you take a bicycle, add a powerful engine, and ride it at 40km/h, then legally speaking you don't have an e-bike; you have a moped or whatever the relevant category is called in the local jurisdiction.
To prevent everyone buying e-bikes from having to deal with safety requirements that are not deemed relevant below 25km/h, the lawmaker's have decided to limit this class of vehicle to those speeds.
At least make it the 30km/h mopeds are allowed to do on bike paths here in Denmark. Those don't require a separate license if you are over 18 either.
Electric bikes seem to cost $1000+. Here in the UK I know plenty of people who can't maintain 25kph for long. And I know plenty of people who spent $1000+ on their bike. But I don't know anyone who belongs to /both/ those groups.
Neither can normal bicycles though (unless you are physically able to do so, but that too holds true for an e-bike).
It's not defined, but the way the law is applied it's based on the rated wattage from the manufacturer (i.e., what's stamped on the bottom of it). Most bikes you can buy in EU go over 250W but the motors are rated by the manufacturer as 250W. My 500W motor will never be legal because it was rated 500W by the manufacturer (even then, in reality it does 700W continuous with ~980W peak).
They should rate the whole system: drive + battery to 250 Wh sustained and maybe 500 W peak power (30s) with motor cutoff at 25 kph. I can do all of these with my legs only so it's esentially a bicycle.
The label thing seems dumb. Of course manufacturers would sell 250 W rated drives to comply.
Part of what is being said is that the higher power levels are more fun.
I do think they should lift the restriction a bit and allow help upto 30 or 35 km/h.
"Ebikes in China... got so out of control that many large cities have banned ebikes (known as ‘silent killers’) from the major roads to cut down on the massive number of traffic fatalities that happen from people riding ebikes. Ebikes have the potential to solve most of the traffic problems in many of the major cities (not to mention global warming), but instead of embracing them in the US lawmakers shun them entirely."
His facts all seem in order. In China, ebikes are unregulated but popular and there's a clear need to regulate e-bikes to ensure that they obey traffic laws. In the US, e-bikes are over-regulated and rare, but the laws aren't strictly enforced either. I think his point is that there's room for improvement in both cases, some form of happier middle ground, wherein (a) laws are sane and enforced (b) bikes are cheap and plentiful.
Also just the general complaint that Chinese tech is cheaper & better quality than American tech.
Of course it does change the legal regime. He will probably (IANAL) need a license, lights, insurance, and so on. Those are all required for good reason, operating a vehicle at that speed is dangerous to those around you.
He just wants a moped that looks like a bicycle.
That's quite the limit. That's one hell of a limit. Most people aren't planning on going 40-60 MPH in a bycicle.
From wikipedia: "When considering human-powered equipment, a healthy human can produce about 1.2 hp briefly (see orders of magnitude) and sustain about 0.1 hp indefinitely"
A 1HP DC motor (or if you want to get crazy with speed control and all that jaz you could do a 3 phase system with a PDM from a torq-controlling pedel or something) is more then enough! Hell we don't even need that. Let's think a .5 HP 1 phase 60Hz motor. This clocks in ~800 watts at continuoious max current but we'd probably not be doing constant drive on this. But let's say that we can pay a little more and find a perfect 750W motor for this at .5 HP. That's a lot of torque given that most people can only sustain .1 HP. This motor (which is crazily oversized by the way) is rated for .5HP @ 3450RPM. 3450RPM at the chain is different to the gear ratio at the wheel. The lowest gear ratio on a bike is about 1.9:1 so our motor would be putting out quite a bit of thrust and even at the reduced torque you'll be halling ass.
Now this is a super oversized motor but anything that can take 750W continuious input is some serious shit. That's one hell of a motor and to complain that that is too small? Get a harley and tinker with that man.
[0] - http://www.ebay.com/itm/MARATHON-1-2HP-AC-MOTOR-M400095-208V...
These people are wasting energy and these super-powered CPUs are a potential fire hazard and we need better regulation enforcement now!
If we restricted high-powered CPUs to people with a license and a documented need, the world would be a safer place for me.
...In all seriousness, 1hp is not serious shit. And motorcycles are significantly faster and more dangerous.
Cheap brakes + 30mph = a bad time
Almost every vehicle, motorized or not, that I've ever driven can lock up the tires. For a vehicle used for commuting or other non-performance applications that's basically all that matters. If you can outbrake your tires (or in the case of a short + high-CG vehicle like a bike, outbrake your ability to keep the thing from flipping over the front wheel) any more braking ability is irrelevant.
For those sorts of uses where a single panic stop is the hardest the brakes will ever work it's basically binary, you either have enough brakes or you don't, and once you have enough adding more doesn't gain you anything.
Performance applications where you're constantly hard on the brakes, off, then back on like a car on a race track are where the scale becomes analog. Larger brakes that are better at dissipating heat will last longer before fading out, and if good enough will not fade during the expected race session.
tl;dr: Unless you're on a race track or similar there's only "enough brakes" or "not enough brakes" and no reason to go better.
It would REALLY suck to find out that some cheap brakes that worked great on the sunny+mildly warm day when you installed them but end up failing miserably the next day when it's a bit wet and they have a bit of mud on them. Maybe the city environment I usually commute in has more obstacles than most, but investing so heavily in your ability to accelerate + maintain high speeds and then sacrificing braking is an incredibly poor decision.
Motored powered bikes are already banned on most trail systems (for good reason).
I'm a regular "utilitarian" cyclist, i.e., I commute by bike year-round, use it for shopping, getting around town, etc. I live in a locale (Madison WI) that is regarded as being bike-friendly, with gradually increasing popularity of cycling. I use bike paths, bike lanes, and low traffic streets, whenever possible.
At present I'd rather stick with a human powered bike because I really need the exercise, and I enjoy it, but I encourage friends to give e-bikes a try if their commutes are not as short as mine or they're not as inclined to deal with all of the issues -- weather, sweating, etc.
For now, the e-bikes are fairly well behaved on the bike paths. It's only a matter of time before there are a lot more e-bikes, probably heading towards a point where we might have to re-think how they are regulated if they get out of hand in some cities, but for now I'm optimistic that we can coexist.
Keeping the power and speed limits seems prudent. People can decide if they want the safety of the bike paths, or the convenience of going faster, by choosing an e-bike or an electric motorcycle.
you can get a 3000w+ motorbike thats electric if you pass a motorbike license ans drive it on the road.
Riide[1] is one company I've seen trying to tackle these problems. It was started by a fellow Hoya (so I'm biased). I find their unique pricing model to be very interesting/attractive as a first time eBike owner. Instead of shelling out thousands of dollars up front, you pay $79 per month for the bike, unlimited maintenance, insurance, and accessories. After 24 months you either own the bike outright or opt-in to upgrade to the latest model.
It might mean my grandparents were able to go see/do more things, if they weren't scared of them.
They are less useful for healthy, young adults, though they might get more people to ride if they made it unnecessary to shower when you were done (it is not a problem to shower at work if that place has a gym, you just don't shower at home, however it is annoying having to shower when you get home again).
probably almost anything?
I didn't either, and then I rode one. Now I get it.
Ride one.
Riding an ebike beats sitting in a car (in traffic or not) any day of the week!
Granted, I'm actually happy with being able to go 20-25 mph on mine, but what I want is just more acceleration so I can get to the max speed faster and climb hills easier/faster.
It turns out, nope. It's still easier and faster. I don't ride e-bikes but I'm happy to see more people on bikes.
I've decided that I'll be buying a reasonable mountain bike frame with disc breaks and retrofitting one of those 1000W Chinese conversion kits onto it.
I have no interest in riding it at its top speed, I just want the power to get up anything more than a shallow incline.
I'm looking at this one.
Except something like 90% of the delivery people I see riding around New York.
> I rode that [2600 watt] ebike like a motorcycle right in the middle of the lane all around the city. I accelerated much faster than the cars did and frankly I got pretty annoyed at how slow the cars really were. Cars clearly were annoyed with me when they saw me at a stop light taking up the whole lane, but once the light turned green I just left them in the dust. This is the way that ebikes were meant to be ridden.
This guy doesn't want an "ebike". What he wants is an ELECTRIC MOTORCYCLE. What he built is an electric motorcycle. (Or maybe a moped, depending on the state, but probably it's an electric motorcycle if it is totally ungoverned.)
I'm glad he likes it -- electric motorcycles, and motorcycles generally, are a lot of fun. Welcome to the club! But let's not pretend that this is some brand-new invention.
All he's doing is building electric motorcycles and then flouting the insurance and registration laws that already exist around them. Nobody is saying that you can't have a 2600W, two-wheeled, electric-powered personal transportation device. What the law requires, in most states, is that you put a fucking license plate on it, and pay insurance, and prove you know how to ride the thing, and generally not act like a dipshit. Which is kind of what he's doing by riding around on an illegal, unlicensed, probably uninsured electric motorcycle.
People build motorcycles all the time. It's a cool hobby. Unlike building your own cars, there aren't a ton of safety regs or crash testing that you have to do, so it's not too difficult to get into. But just because you build one around a bicycle frame (not new -- early motorcycles evolved from bicycles!) doesn't mean you suddenly get to ignore the decades of legal infrastructure which were created to regulate them.
Just keep in mind you can't and shouldn't pretend it's a regular bike anymore. An e-bike isn't really a regular bike anymore, but when limited to bike speeds, I suppose you can effectively pretend it's a regular bike.