Reflections on E-Bikes
ebikes.neighbor-ryan.org
ebikes.neighbor-ryan.org
So yes, it is absolutely great that more people are on the road on an e-bike, now more people can demand their taxes to be invested in proper bike infrastructure helping both e-bike and regular bike riders.
They also broaden the times a bike is used vs. some other mode of transport - for example commuting for people who would not want to arrive at work wringing in sweat and in need of a shower, or carrying heavier loads, or towing a child to school in a trailer over a longer distance, etc.
I am used to Scandinavian, German and Swiss winter.
Cycling with rain or snowstorm, only when no other option is available.
I admittedly do go camping in snow and whatnot but I find the biggest barrier people have to doing these things is not knowing the equipment that you can bring to make it nice. The worst part is actually probably mitigating rust IMO.
The biggest issue I see for higher priced bikes is secure parking (as mentioned in the article). No one provides secure/supervised parking and its tricky to get insurance. You can't really lock any nice bike outside the supermarket and always expect it to be there when you get back.
https://www.cyclingnews.com/features/best-electric-bike-conv...
But if you have to deal with serious hills or want to use throttle-only, 250W won't be enough. IMO 750W is the bare minimum for that, and it requires a bigger motor, bigger battery, and disc brakes.* That costs a lot more and it's easier (and probably cheaper) to just buy the whole bike than convert what you have.
*Disc brakes are essential for higher-powered e-bikes because such bikes move faster and are much heavier than regular bikes. They need more serious stopping power than rim brakes can provide.
I ride with a friend who has gone MTB electric. I leave him behind on the flat but he gets it back on the hills. He's fine for well in excess of 40 miles. Range is mainly an issue of battery size not the wattage.
https://www.congress.gov/bill/107th-congress/house-bill/727/...
Those numbers seem huge. I can only put out about 150W sustained, so a 250W motor boost on top of that sounds like a lot. That would have me at 400W combined which is nearly pro-rider territory.
My road bike (a 10+ year old Specialized) is 19lbs.
A Specialized Turbo Creo (an e-bike) is under 28lbs as advertised.
My mountain bike (regular bike, nothing electric) is 29lbs.
I know 60lb behemots exist, but e-bikes don't need to be crazy heavy anymore.
It's a very expensive risk / unknown result for most folks who don't alredy bike.
"Better bike infrastructure" and "a bit of pedal assist" are both good things that we need more of.
Even in the best possible future, I believe cycling in US cities will involve some amount of mixing with cars for the rest of my natural life (unfortunately!), so I'm not sure "completely bogus if…" is fair.
And anyway, a little extra speed is still useful because it's transportation.
Here's a fun thought experiment: define "places I can go" as "the locus of points within 1hr bike ride of a train station." If e-bikes let me go 50% faster (say, avg 15mph instead of 10mph), that multiplies the accessible area around each train station by 2.25x! I can go more than twice as many places now!
So, a motorbike a passes a human powered vehicle? That should come as no surprise to neither of you. :)
To be honest, I don't get the appeal of e-bikes for the type of riding you do. Getting up to 15 MPH when you're riding for 8 km in a city when stopping for lights should be no problem without disabilities on a decent bike. An 8 km ride takes 20 minutes at 15 MPH. At 20 MPH it's 15 minutes. You'd add 5 minutes off your ride and get some proper exercise.
As a reference, my grandmother rode her bike 12 miles to school and then back at the age of 10.
E-bikes make a lot of sense for longer rides with cargo bikes packed kids, trash, food and whatnot.
Sweat. I do 2km twice a day for the school run in my unassisted mtb. On anything but a cold day, I work up a mild sweat. I wouldn't want to arrive at work in the state I get back in on a warm day.
Many commuters don't want to get "proper exercise" on the way to work. Hard enough getting secure bike storage, let alone a shower.
But I don't want "proper exercise" to be a part of my commute. I want to get to work or to a client quickly, efficiently and with a minimum of effort. I absolutely do not want to sweat through my shirt or arrive at a meeting in need of shower.
Snow =D I live in Canada and we have quite a bit of snow and ice on the roads in the winter. I'm currently waiting for an electric fat-tire bike (RadRover 6) which should allow me to ride to work without getting soaked in sweat.
I think most people in the North America and Europe live in cities that are so flat biking is just like walking faster. Maybe that's where your frame of mind comes from.
Where I live the hills are so steep that it's impossible to bike them solely human-powered unless you're an actual athlete. And even the more modest inclines will make a regular person give up on the thought of biking since it'd be a workout.
E-bikes are awesome for this, as they make tough inclines much easier.
or you have (and use) gears?
It will just take a while
Morning commute is not a moment where I have any interest in exercise, arriving sweaty at work, needing to always carry multiple sets of clothes, ...
I'd rather see it like the dutch, the bike is a tool for moving from A to B. If you want to do this while exercising more power to you, that's not my jam.
As mentioned there is more than that. An entire accelerates from stop MUCH more quickly which adds a significant element of safety.
By the way the bike share ebikes are like 30lbs and speed limited so there are plenty of times when my "motorbike" has been passed in the road by a well-geared human powered vehicle, friend.
I think electric scooters might have a bigger impact on transport as they are easier to store inside.
I don't see any way the rental company is going to stop that. its certainly not like the police here are going to be anything but abusive if you called them about a bike or scooter that you left out for anyone to get at.
For e-bikes in particular the batteries have a lock, and the motor has DRMed firmware on most big name bikes. It hasn't helped theft, it's just annoying for the user. In general the thief can just grab the entire bike and throw it in a truck, then once they're offsite they have as much time as they want to rewrite the firmware or pick the lock so this doesn't really help.
Ebikes could do the same. It would be a shame for the 'hacker' crowd, but with locked down firmware and all parts cryptographically linked by serial number, there would be no valuable parts to strip from a stolen bike.
It normally involves ensuring the device has secure boot, non-rollbackable firmware, tamper-resistant storage for a 'when I last talked to my server' timestamp, and network connectivity to be able to talk to a server to get the lock/unlock status.
It also forces the phone to not allow various offline use (like erasing it and setting up a new user)
Additionally, renters/homeowners insurance. Just make sure it covers ebikes (some do not, like Travelers). Policies usually cover theft away from home.
Foldable bikes to bring in your home are also a solution if you do not have a safe place to secure your bike overnight.
A foldable / small form factor bike seems like a good mitigation factor, and also helps when moving the bike around (e.g. on public transports).
With regular bikes it's way more of a tradeoff because the smaller wheels tend to lower top speed or increase effort a lot, but an ebike compensates for that.
The big issue is an SFF/foldable bike is way more expensive than a regular, and when you add ebike on top it gets into pretty ridiculous ranges.
[1] Propella 7S
It's incredibly useful for doing short journeys. The motor doesn't make the bike any quicker than a normal bike, but it makes hills a breeze and removes that "can I be bothered" feeling from cycling. If I'm feeling more energetic I drop the assist down to 0 or 1 and it turns into a regular cycle ride. If I'm feeling lazy I blast it to max.
There's a lot of negativity around ebikes here, but I think they're heralding a revolution in city transport. Cycling is a great way to get around, but if you're tired or hungry or going uphill it can be a chore. Ebikes remove all that drudgery, and enable people to ride much heavier cargo bikes. Anecdotally I've seen absolutely loads of people riding cargo bikes in my part of London over the last year - way more than ever before. Bikes like the Tern GSD or the Bakfiets can carry multiple kids or a full food shop uphill with minimal effort. They are actually more useful than a car in a lot of situations.
Once I have a secure place to store it, I'm seriously considering getting a long tail cargo bike like the Radwagon or Tern GSD soon. Driving is so much effort compared to a bike.
Wow, interesting that they frame this as a positive. I'm a general advocate for e-bikes but this has been the absolute biggest drawback I've noticed with them: e-bike riders suddenly get all of the speed of a very fit cyclist but absolutely none of the road awareness.
Most "serious" cyclists in my area generally behave pretty well, or at least when they're breaking the law they are usually doing it in a way that has manageable risk to them (I'm not approving it, but I understand it's calculated), while I've seen a lot of ebike riders do some phenomenally dangerous things because they just didn't realize it was dangerous.
I don't necessarily blame the ebikes for this -- I just think riding on "car-dominated roads" requires some experience rather than just more speed. Ebikes aren't a replacement for safe infrastructure.
But I’d definitely acknowledge that a lot of e-bike riders seem to be engaging in risky behavior, quite possibly without realizing the risk.
> I tend to be very law abiding.
Same. I've always tried quite hard to follow the letter of the law on my bike; it seems every counter example is otherwise held against cyclists as a whole. I'm hesitant to criticize ebikes as I do think they're a net good. More people biking is better for everyone.
This made me think of Mr. Riah from Charles Dickens’ Our Mutual Friend, a Jew who had been operating a money-lending business:
> “It looked so bad, Jenny,” responded the old man, with gravity, “that I will straightway tell you what an impression it wrought upon me. I was hateful in mine own eyes. I was hateful to myself, in being so hateful to the debtor and to you. But more than that, and worse than that, and to pass out far and broad beyond myself—I reflected that evening, sitting alone in my garden on the housetop, that I was doing dishonour to my ancient faith and race. I reflected—clearly reflected for the first time—that in bending my neck to the yoke I was willing to wear, I bent the unwilling necks of the whole Jewish people. For it is not, in Christian countries, with the Jews as with other peoples. Men say, ‘This is a bad Greek, but there are good Greeks. This is a bad Turk, but there are good Turks.’ Not so with the Jews. Men find the bad among us easily enough—among what peoples are the bad not easily found?—but they take the worst of us as samples of the best; they take the lowest of us as presentations of the highest; and they say ‘All Jews are alike.’ If, doing what I was content to do here, because I was grateful for the past and have small need of money now, I had been a Christian, I could have done it, compromising no one but my individual self. But doing it as a Jew, I could not choose but compromise the Jews of all conditions and all countries. It is a little hard upon us, but it is the truth. I would that all our people remembered it! Though I have little right to say so, seeing that it came home so late to me.”
Motorcycles are not that much more expensive but they're much safer. The only reason that ebiking isn't killing people is because it's new and rare, but when that changes it's obviously worse for people to be sitting on the edge of the road at around 30mph with nothing other than a cycling helmet and airpods.
What's weird to me is that motorcycles can be had for cheaper than many e-bikes despite the e-bike being a much simpler machine, less range and far slower.
For example, a Kawasaki Ninja 400 has MSRP in the $5200-$5800 range, a nice small local commuter bike but still very capable. Many nicer e-bikes are quite a bit more expensive than that.
I'm sure they know it's dangerous at some level but there's fundamental differences in riding patterns between someone who has thousands of hours in the saddle and someone who just got on a bike. For example in the last week I've seen ebike riders swap in and off the sidewalk, not use helmets, and change lanes without a shoulder check. Experienced cyclists don't typically do these.
It's the same thing as texting while driving. People know it's dangerous on some level, but that doesn't stop them.
So, yes, I do believe AP when if they say their experience in getting to that speed with a regular bicycle gives them an advantage in those situations to someone jumping on a bike that artificially empowers them to that speed.
It's not self-righteousness to want to ride safely.
If you ride in the gutter then drivers will squeeze pass without making a conscious overtaking decision. That is not safe. Most car drivers will take your distance from the curb as an indication of how far out they should pass you.
Not only that but the gutter is full of potholes and sunken drains, these are a major hazard to cyclists. You can't ride around them if you are being squeezed by cars.
It also gives you more room to manoeuvre in case someone in a car does make a mistake.
>It creates a phoney war between different types of road user, as opposed to looking for ways we can coexist peacefully.
Something tells me your idea of peacefully coexisting means me being subservient to you.
It's not a sense of self-righteousness, what they're describing is the recommendation of most cycling groups and association and is entirely about safety.
The sense of self-righteousness is entirely on your side of the network.
> as opposed to looking for ways we can coexist peacefully.
Being squeezed into the gutter with cars zooming by at twice your speed a hand's breadth away is not peaceful coexistence. What you're doing is tantamount to suicide suggestions.
The actual way for "peaceful coexistence" is well-known: grade-separated independent infrastructure (which, to nobody's surprise, is how the netherlands do it all over). Any interaction is a risk except in very low-speed areas (20mph and below). There's a reason why intersections are where most accidents happen.
Also, e-bikes are typically ridden by people who would never think of riding a bicycle in the middle of an A-road, so no need to worry.
In any case, it's relatively easy to do 25mph without a motor which is probably who he's seeing.
The speed cutoffs are where the electric assist stops assisting, but you can always just pedal to higher speeds like any bike.
E-bikes make the first case safer because, as described in the article, the faster you go the more time the driver has to notice you and slow down before crushing or swiping you. Similar but slightly different, you also spend less time in intersections when you go faster, lowering your chance of getting hit by turning or cross traffic
> E-bikes make the first case safer because, as described in the article, the faster you go the more time the driver has to notice you and slow down before crushing or swiping you
I think this is true in some degree, but has a corresponding elongation in the time required to pass the cyclist (which increases the chance that drivers gun it to do so) and reduction in the time to respond when you're going to be cut off. I would suspect it's mostly a wash.
What?
But in the absence of more relevant and recent studies, I prefer to trust my own experience. I feel safer on a bike when I go faster because I'm moving at a slower speed relative to the cars more likely to hit me, and I can get out of the way of others more quickly.
Now I live in a city and just got an eBike. I think it's more or less the same, even though you are more visible. Acceleration can be handy, but speed itself feels more of a risk if you don't have enough situational awareness.
Off course I am heavily biased towards separate bikepaths or roads where bikes have priority[1]
I'm was never a track racer, never even much of a road racer, but at peak fitness I could do a 40K time trial in ~56 minutes, on a time trial bike and a flat course. That only won races where the fast guys didn't show up. 10 years ago if memory serves a 50 year old guy almost broke the 50 minute mark. It's really not as fast as you think it is.
Alex Dowset did nearly 55KPH his last track hour record attempt, and didn't set the record. Power required to go a given speed follows the cube of the velocity so it's nothing near linear to go 10kph faster into the wind at those speed, but yes, in a group, 48kph is attainable for a moderately fit cyclist.
Furthermore, my point wasn't about being "comfortable" as in "breathing easy" it's "comfortable" as in "feeling ok going that fast on a bicycle and knowing I'm relatively safe because of the experience I have.
The site is due for an update, I've been compiling a lot more resources and bolstering some of the arguments with more data, but lately I've been spending a lot of time on these cyclist PoV videos https://twitter.com/CarsDontFitJC
To briefly touch on a few common q's I see cropping up here: - Yes, cycling infrastructure is really bad everywhere in the US (some places worse than others). That's orthogonal to most of the things that are great about e-bikes though. Better infra, and more e-bikes, are both part of fixing the US's horribly broken urban transportation landscapes. - "Rain and snow": it's just not that hard to make biking reasonable in all but the most inclement weather, and anyway, solving {traffic, parking, traffic violence, air pollution, noise pollution, emissions} on the other ≈95% of the days would be extremely good for everyone (including drivers). Making everyone wear a "$40k internal combustion parka" everywhere is not a good solution either!
I really appreciate the thoughtful feedback and discussion I have some related projects with cool software angles I am hoping to post here as well, soon™
Motorcyclists say the same thing about speed being a benefit and maybe it is in some cases, but if you look at the stats, the faster the bike, the more likely you will die. Speeding is a factor in 32% of fatalities.
I'd be surprised if it's significantly different on an e-bike.
I would assume the same about motorcycles and ebikes, but presumably the threshold would be lower due to lack of protection (motorcycle helmet and armour not as safe as a metal shell with airbags).
So I wonder where that curve starts to rise up on bicycles and ebikes considering they wear just a bicycle helmet and no armoured clothing usually.
(I loved riding ebikes in China (Kunshan) with wide protected lanes that were totally separate from traffic outside of city center (where speeds were low and congestion high, negating they need)).
There’s a pretty big difference between going 10 and going 20 too. Physics lets us know that 2x the speed of a mass carries 4x the energy, so a 20mph crash does 4x the damage of a 10mph crash. I’ve had a bike crash into rocks at under 20mph that could have killed me were it not for a helmet and padding. (I did not walk away unscathed, years later I can still feel the injury to my shoulder…)
Crashing at 60 on a motorcycle is pretty likely to kill you. Crashing going 20 on a bike might break bones - as long as you hit something stationary, rather than throw yourself in front of a car doing 40. Crashing at 10 mph and you might be able to jump off or walk away with only scratches.
It’s also fun to think about how crashing at 1000 mph is not that much more likely to kill you than crashing at 60 mph on a motorcycle. At some point, the speed is enough to do all of the damage.
In that range, and in mixed traffic (which is unfortunately most urban riding in the US), a 5mph difference can be a step change in terms of whether drivers even feel the need to pass me at all. 15mph is only 50% faster than 10mph, but can totally flip the "who's passing who" dynamic from "cars passing me frequently+aggressively" to "cars hesitate, back off, and then I get ahead / pass the next cars in line at the next light."
Here's an account where I've been posting videos that illustrate this a little more viscerally: https://twitter.com/CarsDontFitJC/status/1457490588320817153
Basically, ebikes are great when you don't need much anything else besides your self.
also, many bike friendly paths don't allow electric bikes (sometimes not enforced and it will probably change in the future though)
It's true that there are certain compromises compared to a car, but a car has its own set of compromises (mostly cost + parking being more annoying in a city).
On some level they're aware of ebikes existing, or, y'know, the Dutch, but for some reason the thoughts of "the Dutch bike everywhere" and "the Dutch have children" never quite connect in their heads.
That said, you definitely don't need to be particularly fit to bike there. The bike infrastructure is quite good, and yes it helps how flat the country is (though this is becoming less of an issue with the rise of ebikes).
In addition there are places where bikes are massively inconvenienced vs cars.
The classic example is the (I’d guess) 6 story flight of stairs to walk your bike up to use the harbour bridge. There are other examples like this, around bridges.
These add a lot of time and sweat to a commute making it more convenient to drive or eat a train or bus.
Cycling for pleasure, if you drive to the right places, is still possible.
Bikes also need a good amount of infrastructure, and most cities do not have that right now. Given its usually car drivers that pay taxes for roads (either a direct road tax or through fuel) it not really a suprise that they are designed for them.
In most places the cost of roads (especially local roads) is being partially covered by general taxes. Where I live is it around 50%.
[0]: https://terrapass.com/product/personal-carbon-offset-grouped
[1]: https://www.bidnet.com/resources/business-insights/us-govern...
[2]: https://www.eia.gov/tools/faqs/faq.php?id=23&t=10#:~:text=In...
[3]: https://www.eia.gov/energyexplained/diesel-fuel/use-of-diese...
Hopefully this will (in the US) lead to cities taking the idea of low-speed vehicles more seriously, which are a good fit for medium-density US cities with room for putting in grade-separated paths. For a bonkers example of how it isn't all that hard in moderately wealthy US new development, see Tom Scott's video "The City of Golf Carts" [1] which describes the Atlanta suburb of Peachtree.
Total cost of ownership of a car is really high
Granted this is not the average cost of car ownership but a car chosen for low total ownership cost.
>a car chosen for low total ownership cost.
I own and drive a car that I bought with the intention of owning and maintaining cheaply, too. I am fairly anal about maintenance, so the costs associated with that are actually inflated from what they could be.
I live in Southern California, apparently a very expensive place to be.
I own a reliable used car that I bought for fairly cheap (sub 5000usd).
I pay about 82 dollars a year for registration, and 85 dollars a month (with a good DMV history) for insurance.
I spend around 1200 dollars on maintenance a year generally, but it has been as low as 500 a year.
So, 2400-2900 a year after the initial purchase. It's more expensive than some places -- but not ourageous.
Licensing is a lot cheaper than Japan, at least.
Tax is high here. $330/yr (after 2yr) and $210/2yr (after 5yr).
Here's a reasonable one year old used car in Los Angeles. It only approaches the 40k number after five years of ownership.
https://www.edmunds.com/chevrolet/sonic/2020/cost-to-own/?st...
Insurance costs €150/year. I drive around 10,000km per year, which at today's prices (€1.50 per litre) fuel costs €900/year.
I paid €10,000 to buy the car and today the same aged cars will sell for around €6,000. That gives a total cost of ownership (excluding fuel) of €1,100/year or €2,000/year including fuel.
For my family's usage that works out cheaper than public transport + renting a car for longer trips.
Old cars cost less upfront but often more on maintenance.
For most people housing > car > food (relative cost)
I think that 8 billion cars on this planet would not be reasonable.
This is a political issue about urbanisation and transportation, the next generations will have to make choices.
I'm comparing new cars to new e-bikes and, sure, in both cases you can get something "pretty good" for ≈half the average new {e-bike,car} price. Some people will get something "very good" for 2x the average!
From what I can tell the research supporting the $40k average (or, alternatively, $800/mo) seems reasonable:
https://www.cnet.com/roadshow/news/average-new-car-price-202... https://www.motor1.com/news/370609/average-american-monthly-...
Definitely something I want to hash out and cite more though.
(a) speed = reduced reaction time. No more riding with your headphones on ---that's pretty safe and common to do in the Netherlands--- as you need all your senses on alert to react on any road emergency. (b) speed = less excercise for short-midrange routes. Your 20' bicycle ride to work becomes a 12' e-bike ride, and requires less effort. (c) speed = more room to be an asshat. Most e-bike riders behave, but as more and more youngsters can afford an e-bike, things change. Worse, youngsters often go for those heavy, fat-tire e-bikes that are just as dangerous to crash with as a regular moped. And just wait until those become popular with the (already annoying) bicycle-riding tourists.
But to be fair, an e-bike can also pay of its purchase within a year in cities with high rent prices. This includes Amsterdam.
What a missed opportunity.
Pork, short for "pork-barrel politics", is a US term originating in the 19th century which refers to the practice of spending money in a legislator's district to get their support.
Yes, it's a missed opportunity, but no bill at all would have been an even bigger one.
Before ebikes, you either rode a bicycle, or moved up to a motorscooter or motorcycle, which are much more regulated. The problem is, ebikes are stealth motorscooters. They go really, really fast, for sustained periods of time, and yet are as thin and quiet as a pedal bike.
I just started riding motorcycles and you are told that you should ride as if you are invisible, and it's totally true. Ebikes, however, are even worse. You're still going 30, 40 or more and yet, you're even less visible to traffic and less protected should something go wrong. This is going to be a huge issue as these things get more popular. Which they will be.
My son and I are getting really into ebikes and e-dirtbikes and e-motorcycles. We're building our third right now [1]. They really are a totally new and interesting area which, like how Tesla changed perceptions of electric cars, ebikes are going to do the same with two wheeled vehicles. For those of us in temperate areas like California, it might represent a real fundamental shift in how we all commute. Laws are going to need to be changed quickly.
For those of you interested, definitely start looking at all the activity around ebikes and e-motorbikes online [2]. There's a quickly growing community of enthusiasts who are building their own bikes from scratch, modding/upgrading their off-the-shelf bikes, converting old dirtbikes and more.
It really feels like we're at a tipping point. Even HN has had several articles about it in as many days, even though I think most of the articles and conversation really missed the point: Ebikes are a 10x innovation and we should really be thinking of what that will mean.
Not really? Class 1 and 2 ebikes in the US top out at 20 mph. Ebikes in Europe usually top out at 25 km/h (15.5 mph). Even 20 mph is achievable by a moderately fit person on a road bike for a sustained period of time.
I'm not sure why the downvotes. Oh well.
No ebike is hitting "70mph". The hearing and tires avg l aren't good enough and the battery didn't even deliver enough power.
Really? It's not that hard to Google this stuff.
Call it whatever you want, these are motorcycles.
I know because I've done it.
And it scared me so much, I had both myself and my 19yo son go take a motorcycle course this summer to get our M1s before we ended up wrapped around a tree or under a truck.
At least in the EU (and the UK) e-bikes are limited to 25km/h, about 15.5m/h. Even I can cycle faster than that. And vehicles like moped's were extremely common in European cities a decade or two ago, which fit the same characteristics as en e-bike today.
Not really. The various e-bike classes all have assist cutoff speeds which are lower than what one can pedal a regular road bike, so e-bikes aren't any faster. It just takes less effort and sweat to keep the speed, but the actual speed isn't higher.
Ultimately, law enforcement need to start paying attention to bike thefts (ie, we need a "grand theft auto" type infraction). Not sure how this happens.
Sort of funny if you know the Festool brand as they’re considered very premium.
Isn't that a festool vacuum (like a shopvac), with festool tool boxes on top?
Count again:-)
Did that via Gitbook WYSIWYG editor, not sure what all those other changes are about, hopefully didn't break anything
F = 0.5 mv^2
The electric nature of these bikes makes them go faster than regular bikes so the force in case of an accident is increased by the square of increase in velocity. Add the increased mass of these cargo bikes and the force on impact is very large. It's very surprising there is no regulation on use of these bikes on normal bike lanes or sidewalks which I see often in places like San Francisco.
What will hurt is whether the brakes are sufficient to stop that mass, which naive conversions have. That makes the difference between stopping in time or not.
Thankfully, it'll never happen.