Hacker News new | past | comments | ask | show | jobs | submit login
Not a Wheelchair [video] (youtube.com)
354 points by priyanmuthu 89 days ago | hide | past | favorite | 144 comments

Reminds me of this passage from Cory Doctorow's book Walkaway:

"You realize that they're exactly right," Sita said. She smiled, stopped. "You know, when the first walkaway prostheses project started, most of the people contributing had lost an arm or a leg in Belarus or Oman, and were tired of paying loan sharks for something that hurt and barely worked and could be remotely repossessed by an over-the-air kill-switch if they missed a payment. But once they got here and started living, realized how much had been left on the table by conservative companies that didn't want to get into a patent fight and didn't see any reason to add advanced functionality to something that you didn't have any choice about, they got radicalized.

"They stopped saying 'I just want to make an arm that'll get through the day,' and started saying 'I want an arm that does everything my old arm did.' From there, it was a short step to 'I want an arm that's better than my old arm.' And from there, it was an even shorter step to 'I want an arm that's so outrageously awesome that you'll cut off your own to get one.'

Reminds me so much of Machine Man by Max Barry. "Charles Neumann is a mechanical engineer working at Better Future, a military research company. After losing one of his legs in a hydraulic clamp, he begins to tinker with leg prosthetics. The replacements he builds are so advanced that he amputates his remaining leg in order to make full use of them."

Gosh I really love-hate that book. It comes up over and over and over again despite what I consider shoddy writing. It's a bit of a blueprint for how to make the best of a foreseeably shitty future.

My feelings as well. But this one sentence made the book worth it - it is a commonplace thought that should've occurred to most others, but anyway was a clearer articulation than whatever I'd had:

"I'm suspicious of any plan to fix unfairness that starts with 'step one, dismantle the entire system and replace it with a better one,' especially if you can't do anything else until step one is done. Of all the ways that people kid themselves into doing nothing, that one is the most self-serving."

Love that quote.

I think why so many people want to "dismantle the system" is exactly the same reason that less-experienced engineers push for rewrites: it seems easier to build a good system from scratch, than it does to build the skills required to refactor what you already have into what you need.

(Not to mention, the skills to understand what you actually need!)

Because, more often than not, it turns out that the old system had evolved to deal with a crazy number of edge-cases that were, in fact, really, really important.

Also, and connected: there seems to be this odd zeitgeist of "make other people solve things".

Like, most of us think homelessness is bad, and most of us want to help the homeless, but how few people actually directly invest their own money -- which I would argue is more important than donating time -- towards actually solving that problem?

If I lived in the US, I'd be half-tempted to do a YouTube series where all I do is run around, ask people what they think the biggest problem is in society, and then ask them how much money they've spent to help fix it. Might be interesting, especially if I could do so with a curated list of charities (e.g., ones that don't just pocket the money for nefarious purposes)...

> Because, more often than not, it turns out that the old system had evolved to deal with a crazy number of edge-cases that were, in fact, really, really important.

The problem is that a lot of crufty old systems evolved to deal with a crazy number of edge cases that no longer exist.

Or they started out with a bad assumption, and then had some hacks applied to deal with the problems that caused, and then had some other hacks applied to deal with the problems those hacks caused, until nobody can see from one end to the other.

It's important to be able to tell the difference between something which is complicated because it's dealing with a complicated problem and something which is complicated because it's hot garbage.

> Like, most of us think homelessness is bad, and most of us want to help the homeless, but how few people actually directly invest their own money -- which I would argue is more important than donating time -- towards actually solving that problem?

The trouble with many of these issues is that they're results rather than causes.

Why is someone homeless? For one person it's mental illness, for another it's unemployment, for another it's drugs, for another it's housing costs.

So if you want to solve homelessness, all you have to do is solve mental health, unemployment, drug policy and zoning. And then six other problems that caused six other people to be homeless.

Which, it turns out, somebody needed to solve anyway, but now you've got to pick something to focus on. And I think that's where people have trouble.


> The problem is that a lot of crufty old systems evolved to deal with a crazy number of edge cases that no longer exist.

Totally true! But it's usually a lot easier to factor those cases out than to rebuild the entire thing from zero.

> It's important to be able to tell the difference between something which is complicated because it's dealing with a complicated problem and something which is complicated because it's hot garbage.

My rule-of-thumb here is "If you have to force people to use it over alternatives, you can safely throw it out. And possibly not even bother replacing it."

> So if you want to solve homelessness, all you have to do is solve mental health, unemployment, drug policy and zoning. And then six other problems that caused six other people to be homeless.

If you want to solve all homelessness, sure.

But there is something to be said for helping fix real problems, for real people, now. To make the world that tiny bit better. And in doing so, you gain a more nuanced view of the problem you are solving, which makes you better at proposing and evaluating proposed solutions.

I think too many people end up in this weird place where you have to solve either all of the problem, or none of the problem -- evolutionary change just doesn't seem to be on the table.

Honestly, for me Doctorow and Heinlein occupy many of the same spaces. It isn't great fiction, but the ideas presented coupled with 1-2 paragraphs of absolute brilliance make it worthwhile. And both have their cringey moments, although Heinlein definitely takes that cake.

> 'I want an arm that's so outrageously awesome that you'll cut off your own to get one.'

Probably not the first and definitely not the last time that idea will be tried in sci-fi (and out of).

I can't recall what story but there's one where operations people have twice the usual complement of fingers.

There's also a guy who hacked the interface for his prosthetic arm to directly control a sound board. Why go analog-digital-analog-digital-analog when you can skip two steps in the middle?

Most of the comments have criticized the price point for what you are getting; however, I would say this looks like a great quality of life tool for disabled individuals. If you are wheelchair bound, there are a number of terrains that a traditional wheelchair will not operate on. They even point this out with their rig on beach sand. There are designs that handle sandy terrain [1], but they would not work well on other surfaces.

Without knowing much about the couple's relationship, I would say they are trying to create a design that allows for other outdoor terrains, such as a dirt road. If you imagine a traditional wheelchair design, the subtle bumps and dips on a dirt road would make it taxing for the rider or anyone assisting them. Jerry's Rig tries to mitigate those issues to offer a quality of life improvement so that wheelchair bound outdoorsy people can still be outdoorsy people.

Like codekansas said, people can very quickly scope creep into making an all together badass arm when all the person wants is something to get them through the day.

[1] https://www.sandriderusa.com/product/sand-rider/

The price point for the beach wheelchair you linked is $2,440.00. That's about half the price of this rig, and it does not get you to the beach. You need to have (and park/stash?) another wheelchair for that. Oh and you have to have someone push you.

By the way, I read @codekansas' comment [1] not as a warning about feature creep, but as a comment on the inertia in the medical industry (emphasis on "industry") versus just a few enthusiasts who don't feel bound by patents, conventions and markets, and simply want to build something to improve their lives.

[1]: https://news.ycombinator.com/item?id=23703179

The hint is in the name. This thing simply is not a wheelchair. It isn't even trying to be one. It is meant to carry a folding wheelchair as cargo. Therefore we shouldn't compare it to wheelchairs, those things capable of doors and elevators. This thing is a different type of vehicle, something between a bicycle and an electric go-cart. It isn't for daily mobility, for taking to the grocery store. It is for a specific type of wheelchair user: those with dexterity and strength to handle and setup the machine who want to get onto trails at bicycle speeds.

Yeah I think this is awesome.

I've thought about what a cool wheelchair would be like since the 'regular' stuff that exists seems disappointing. I wonder if e-bikes and more accessible battery packs are what make this possible now.

I think there's a lot of opportunity in this space for making something that you'd actually want to use if you were disabled.

A lot of the stuff that exists in the current market seems overpriced (though I'd guess there are regulatory reasons for this and it's not a simple fix).

I'm glad they made this, hopefully more people will hack on things like this too.

> Jerry's Rig

His name is Zach...

Thanks, I'm not a subscriber to their channel, so I went off the channel's name.

Ha the same, I'd assumed it was a play on his name. He does some great videos but I don't love his presenting style - but the content is great.

I think its his father's name.

I don't know this guy, but he refers to himself as Jerry in the video...

I think the biggest impact of this is the price. There are other similar products out there (Bowhead and Outrider come to mind), but those are really expensive. In a world where mobility product prices are through the roof (my power wheelchair costs north of $50k), selling something like this for under $5k is quite incredible.

It's because it's not a wheelchair, so it doesn't need to meet the regulatory standards, nor does the insurance middleman pricing kick in.

And one might argue, it isn't a usable product without assistance. Per the video, she couldn't even lower the handle without him to exit, and it certainly isn't getting in/out of even wheelchair converted vehicles by itself.

Not to mention electrical power (Vs. gas in the competition) definitely could result in the user being stranded, even if it has a power-usage monitor (given how environmental factors can impact non-air conditioned batteries).

I mean, speaking for myself mainly here, but I wouldn’t really feel comfortable in _any_ off-road situation without a buddy with me. And most of my friends who handcycle regularly generally always have someone with them.

But then again I don’t want to exclude the population who are capable of doing this independently.

Able or not, it is usually a good idea to have a buddy when you do this sort of thing.

That thing gets a flat tire or rolls over and a buddy is going to come in real handy.

> Per the video, she couldn't even lower the handle without him to exit

This really looks like something that can be improved relatively easily. Instead of disconnecting, the pole could slide along the bar when released and click back when raised again. In other words, it's either an early implementation issue, or a cost saving trick, not a spec problem.

This is V1 and it is pretty good. Maybe they can address those concerns in V2?

Sure but neither do the Bowhead or Outrider vehicles I mentioned. The cheapest Outrider starts at $10k and Bowhead doesn’t even mention base pricing on their site, so a 50% reduction in cost is still really good. Although I will say that I’ve tried an Outrider and those vehicles are way more complex.

Edit: Actually I checked again and Outrider has a semi-off-road vehicle for $5k now which is pretty cool.

The fact that it's made from off-the-shelf parts designed for more mainstream use-cases (e-bikes) probably also helps a lot. Economies of scale and all that.

> my power wheelchair costs north of $50k

Holy mother, I had no ideas they could be so expensive!

Out of curiosity (and unfortunately because I might need one myself before too long :(, I just had a quick Google here in the UK, and I can't find any more expensive than $3k. I'm not sure if you meant "normal" electric-powered wheelchair, or something else?

Yeah I use a rehab chair. It’s specifically designed for the non-ambulatory whereas a lot of the cheaper wheelchairs are designed for the semi-ambulatory. My specific model is the Permobil F3 which another user found starts at £10k in the UK.

Thanks, I'm totally ignorant of what is out there for mobility so figured I'd be looking at the wrong thing :)

There's cheaper power chairs out there.. the Air Hawk is like $2k, though obviously not for everyone. These aren't going to be fitted or customized for your injury/ability, so they'll be worse but cheaper.

Yeah but if I'm going to sit on something for 14 hours of the day for every day of my life it better be comfortable and not give me pressure sores. Also my level of injury necessitates lots of additions.

Oh, totally! There's a reason that such mobility aids are so expensive. My point was that things like the "Not a Wheelchair" can be cheap because they aren't used full-time, the same as for the Air Hawk.

There's a lot of people that use wheelchairs for part-time use. When I was considering getting one, I could walk a couple minutes but couldn't go farther without injuring myself further. Having something cheap that could get me some freedom back would have been worth it, even if it's not perfect.

>my power wheelchair costs north of $50k

What kind is it? Here in the UK the typical price I'm finding is ~£1000, with high end models ~£3000



I use a Permobil F3 with a lot of additions. The price I mentioned is the insurance price in the US and in many cases self-pay will bring it down but it's often still prohibitively expensive. I had to self-pay for an add-on on my current chair and that was $2400 itself. Oftentimes in the US, manufacturers will only sell products through a licensed DME so you have to pay a markup there too.

Yes, I was clearly looking in the wrong places. I can see the Permobil F3 listed in it's base spec for ~£10,000 over here.

The wide-spread use of ebikes makes components for this kind of thing much more affordable.

I think e-bike technology is going to get adapted to all sorts of new uses like this. I think there's a lot of opportunity to create great vehicles for people that will offer a good accessibility.


This video shows bikers of many different abilities using many different kinds of bikes and it shows how versatile bikes can be for different people.

I'm kinda curious why it's a quad-wheel system rather than a tricycle. At 2:28 in the video I linked, there's someone paralyzed that uses a tricycle to go off-roading (two wheels in the front, one in back with a hub motor). I'm not saying there isn't a reason for the 4-wheeled system, I'm just wondering what if offers.

Far more stability, right? I assumed that's why 3-wheel ATVs are banned pretty much everywhere.

Having the front be single wheeled leads to the a lot of instability because turns change your center of gravity. I just bought a recumbent bike and I had to search extensively to find a nice two-wheeler because the 2 front wheel 3-wheelers are quite popular, just like the motorcycle equivalent. Most bikes and motorcycles with three wheels have the same steering linkage you'd find in a car.

Be very careful with two wheel recumbents, I've got half an Ikea's worth of steel bits in my right leg on account of one. The danger is in when your foot slips off the pedal even for a moment and hits the pavement on the downstroke, you'll brake with just that one foot and it is a feed-forward mechanism that you can not break out of. Nasty, to put it mildly. If I had foreseen that particular failure mode I'd have either foregone the bike entirely or I would have placed something underneath the cranks to catch my feet should I ever go there. The lower the bike the higher the risk of this happening.

Thanks for the advice! I've picked up a tall one, and I'm definitely going to keep your story in mind when choosing my clipless pedals to hopefully minimize that risk.

> Having the front be single wheeled leads to the a lot of instability because turns change your center of gravity.

Cue Mr Bean and a Reliant Robin: https://duckduckgo.com/?q=mr+bean+reliant+robin&iax=videos&i...

> Far more stability, right? I assumed that's why 3-wheel ATVs are banned pretty much everywhere.

Those were single-wheel in front, two wheels in back. I guy from my high-school rolled one and broke his wrist, back in the day.

That was a really heartwarming video. I'm guessing that The Rig has four wheels in order to support carrying things (they mentioned in the video being able to strap a chair or coolers to the back).

regarding 3 wheels vs 4, I see 4 wheels having some advantages. If you picked a tricycle configuration you'd want two wheels up front and one wheel in the back for stability. If you have steering and drive in the front, you have a more complex system that doesn't get good traction going up steep hills. If you put drive up front and steering in the back you lose good handling at speed. If you put steering up front and drive in the back, you only have one wheel drive.

From growing up on a farm, tractors with tricycle gear in the front don't work as well in the snow, and I'm not certain why this is. I think it's because you have to break three paths through the snow rather than two. In addition, a four wheel setup in snow tends to go in a straight line. If you get tricycle gear stuck in a rut, you're going sideways and it can be difficult to maintain a straight line.

I have cp, and used to have a trike. I loved that thing to bits, but I'd never use it in the city. Way to wide for bike lanes and riding it on the sidewalk is illegal.

Also, lets be real, this assumes side walks and bike lanes are even available.

Seems like they wanted to leave the back for carrying loads, which you can't do as a trike.

It is an exciting time for sure. E-bike technology could change the world massively for the better.

Quibble: "Stay safe, wear a helmet", in a video full of action with no helmets.

I like the product, though. Seems like good people trying to do a good thing.

It's pretty cool.

Good medical equipment is always going to be expensive.

Mist disabled folks won't be able to afford this, and, of the ones that can, they may not want or need them.

That doesn't mean they shouldn't make them, but they probably won't get rich on them.

If anyone watched the Apple keynote, one of the sessions was introduced by Meg Frost, who rides the most badass wheelchair I've seen: https://youtu.be/GEZhD3J89ZE?t=1299

there's a Kenyan guy[1] who makes electric wheeelchairs out of recycle laptop batteries.

and it has some nice off-road capabilities.

I can't find his website but he appears to be active on instagram[2]

1. https://www.bbc.com/news/av/world-africa-49528426/kenyan-inn...

2. https://www.instagram.com/linccelltechnology/

I like how the Swincar has a roll-cage.

Even if the "Not a wheelchair" has a lower speed, and less off-road capabilities than the Swincar, it still seems like roll protection could be a useful safety system.

I guess they're relying on the light[er] weight?

Your comment reminded me of a motorcycle racer I knew who was paralyzed from the waist down. He had a few funny stories about coming off his bike and having his legs broken and bent like a pretzel. The track martials would come over and just about faint at the sight of it, he often had to calm them down. He'd get looked over by the medics and drive himself to the hospital to get a cast put on.

That really can't be healthy for him, can it??

It's not something you should do deliberately for sure. Because he wasn't able to move his body weight on the bike the bike had to lean even further than any other rider so he was often very close to the edge. He also always had to start from the back because he had to have people to launch him.

They might be able to sell a roll cage as an add-on. Probably most people won't need that but might be good for some. It looks like the frame would be simple to mount to.

Looks cool but I guess the price is at least three times that.

Is no one going to comment about how it looks and sounds like their voices were overdubbed by professionals? It just doesn't sound natural _at all_. I know it's not actually overdubbed, but it's so smooth, the inflection is perfect... it's freaking me out.

I highly recommend subscribing JerryRigEverything channel. The host's (zack) primary content is dismantling smartphones at same time reviewing it's features fairly.

I had unsubscribed to every other smartphone review channel as I'm not going to change my smartphone every other day and at the same time I want to keep myself apprised of the developments in smartphone hardware; JRE serves me perfectly for that.

He got very political some years ago (trump/clinton stuff) and I unsubscribed.

He adds humour in his narration, which includes world events sometimes, but he's extremely nuanced.

The only political video I've seen of him is the recent video he did with other youtubers asking people to vote, that's all, there was no mention of any party and in-fact someone in the video explicitly said 'vote for anyone, but please vote'[1].

Unfortunately, asking people to vote is seen as a threat by one side of the political spectrum; however foolish that is in a democratic country.


what? I occasionally watch his videos. The only thing political i heard him say was about rights to repair, apple fighting repeatability, or small rants how apple designs for anti repairs.

He approaches things with humor and uses the current news. For instance in one of his smartphone videos "And this phone has a xyz mAh battery, and also if you look close you can read Jeffrey Epstein didn't kill himself."

This is without taking a stand in the matter - which is good.

Does Facebook have a patent on their snooze feature? It would be a nice addition to YouTube and Twitter.

There was a discussion in my problem validation platform regarding 'saving offer notifications'[1] for later use. If that is implemented, perhaps we could have snooze feature for any notification on it.


Shows simple is sometimes most effective.

While a device with bunch of features would be better, most people with disability don't need features, they need something reliable to move around that doesn't require huge fortune to keep running.

From what I see this thing is so simple nobody will have trouble repairing it with regular tools and off the shelf parts so most people will be able ask family member to get it repaired.

The drivetrain and steering assembly have definitely been designed to make it cheaper to build and easier to maintain which I think is a good thing. I wonder how much more expensive and complicated it becomes to have 4WD.

My guess is that accounts for about 30% of the costs.

The existing Rig is $4750 USD and is rear-wheel-drive only. Are you saying it would cost 30% more to make it 4WD?

Given that the electric monitor is in-line, and there's no gearing or shaft, I mean is that such a stretch? The easiest way to make it 4WD would be a second electric motor, which could easily be 30%.

Driving the front wheels is more complicated because the front axis is used for steering (it might be easier to go for two motors there, and, if you go there, 4 identical motors might be the better choice for maintenance/repairability).

I think you also would need to guarantee that both engines are aiming for (about) the same speed, even in corners or when tire pressure changes. That might require something technically similar to ABS.

Also, does this have a differential on the back axis? I couldn’t spot it, but that may be because I don’t know what they can look like on these relatively low-powered devices.

> I think you also would need to guarantee that both engines are aiming for (about) the same speed, even in corners or when tire pressure changes. That might require something technically similar to ABS.

Equal torque is good enough. They'll settle to speeds consistent with turning, etc.

Since they're independent motors, you don't need to worry about the case where a wheel is spinning stealing all of the torque.

> Also, does this have a differential on the back axis? I couldn’t spot it, but that may be because I don’t know what they can look like on these relatively low-powered devices.

I don't see it. Often ATV, etc don't have them: you get enough wheel slip on low traction surfaces that turning works fine, and the prospect of one wheel with impaired traction stealing all the torque is bad.

There's those Russian sidecar bikes.. they have just a clutch for the second rear wheel. If you're on a paved surface, you use one driven wheel, but if you're offroad and could use 2WD, you can engage the clutch (and slippage does the job of a differential).

> Equal torque is good enough.

Eh, you'll still want to redistribute torque if you're planning to accelerate hard. After all, accelerating shifts weight onto the rear wheels, giving them more traction and the front less.

Front wheel skids aren't acceptable as you use them to steer. And limiting your rear wheels to the amount of torque that would make the front wheels slip means you're leaving a fair bit of performance on the table. And presumably getting more performance is the whole point of going 4wd!

> Front wheel skids aren't acceptable as you use them to steer. And limiting your rear wheels to the amount of torque that would make the front wheels slip means you're leaving a fair bit of performance on the table.

Or you can just size your motor(s) a little smaller in the front. Or just cope with this.

> And presumably getting more performance is the whole point of going 4wd!

Being less likely to get stuck and not be able to put down torque at all vs. a differential and RWD is the big performance win. Being able to run each wheel precisely at the limit of traction is great if you want to be quick off the line, but that's not why most off-road vehicles are 4WD.

The motor does appear to drive the rear with a chain drive


Not sure what a good way to run power to the front of it would be esp given the steering system and two front axels

Did he say there’s no differential? Solid read axle? That could be hard to turn on non dirt surfaces?

At those speeds and slip of the narrow wheels that's manageable. With a lot of weight on it it would be more problematic. At least now when on slippery surfaces you have some traction, a limited slip differential would be tricky to make cheaply and would consume quite a bit of energy. A normal diff would cause you to get stuck very quickly.

He said so and it does seem to have solid axle and it only shows it driving on dirt and grass.

One way to solve it would be to have only single wheel powered. If you get that one powered wheel lifted you could shift your weight to tip entire vehicle (assuming you took care to load it evenly).

Or just use a limited slip diff. Allows some slip for cornering, but only, well, a LIMITED amount you don't end up with one wheel in the air spinning like mad and the one with traction not moving at all.

I know he's trying to be cheeky by saying its "not a wheel chair" to get around FDA regulation, but that's not how it works.

Its clearly being marketed to disabled people as a mobility device, which makes it a wheelchair, and makes it a class II medical device that must have design controls.

He's in for a rude awakening by a visit from the FDA.

Can anyone point me in a good direction to start making something like this myself? I've dabbled with arduinos but never really large electric motors and battery packs. I think it would be a lot of fun to make myself an ebike or whatever this thing is.

Here's a couple similar components I used to build an e-bike. Get at least a 1500W hub motor [i] and a high capacity battery pack [ii].

[i] https://www.amazon.com/JJBOOM-1000W-Electric-Bicycle-Convers...

[ii] https://calibike.com/product/lithium-ion-72v18ah-ultra-light...

If I were doing this, and it looks like a load of fun anyway, I'd start with go-kart frame designed for a lawnmower engine. You'd get a roll cage, 5 point seatbelt, brakes, hand controls for throttle. Just add batteries, electric motor, and electronics. Like this one:


The 'battle robot' sports scene does a lot of DIY involving batteries and wheelchair motors.

I'd look into those user groups for info.

You might find some inspiration in Tom Stanton's [0] videos, he made his own e-bike and documented the upgrade cycles since v1. Just recently he made a summary video about how to start making your own e-bike.

[0]: https://www.youtube.com/user/tomstanton282

If you actually do this, I'd love to read a blog about it!

I wonder how those rear wheels handle corners. I'm a little surprised they didn't use two independent drive motors, versus a single motor and solid axle, which could be extended to implement an electronic differential.

Indeed, this thing will likely eat tires if used on-road a lot. Without a differential, it'll also be harder to steer and will want to "push" through the turns. You can see this at 2:31:


The turning radius isn't that great, and the lack of a differential helps explain why. Definitely an interesting design choice.

Version 1.0 will always be a functional proof-of-concept. They have the basic platform, now they can start iterating.

If they've gotten this far, they've already been iterating. In fact he says so at the beginning. "A year ago I welded two bicycles together..."

Having built two recumbent vehicles (a bike and a trike) I can say that the options for a rear wheel drive are either:

- Single wheel drive

- Dual wheel drive with freewheeling action

   - The inside wheel is driven in turns
- A differential

   - The outside wheel is driven in turns
- No differential at all

   - Both wheels are driven equally all the time
He's chosen the latter. It's simple, cheap, and provides the best traction in almost every situation except a turn. It's a good compromise for where this thing is intended: Dirt. If it were optimized for street use, he'd just drive one wheel, which is what I'm doing with my own trike.

For reference, this is my current trike build. It's not done yet. Needs finishing, and paint:

https://i.imgur.com/pnrDQMS.jpg https://miscdotgeek.com/wp-content/uploads/2019/11/IMG_20191...

Almost think the ultimate solution here would be 2 motors, one per side, and skid steer action. Can then pivot in place, or turn at any radius desired. Would map quite naturally to the two joystick control system too.

You can drive all 4 wheels then which will do even better off-road, and the suspension actually gets a lot simpler since you can totally do away with streering and all the assocaited geometry.

The problem with skid-steer is that it tears up surfaces with high-traction tires.

Dual wheel drive with freewheels needs a way to block the freewheel to be able to reverse.

Indeed. This is a unique feature to his machine because he's not concerned with pedal power at all, and that opens up a lot of possibilities.

Probably just fine. It seems they intend this mostly for use on soft surfaces, where the lack of a differential isn't really an issue, even on large vehicles, because the surface itself is compliant enough to make up for the lack of differential action.

But even on a hard surface it might work just fine, because the turning radius looks pretty shallow.

The advantage is that a solid axle is simple, cheap, reliable, and performs well in low-traction situations.

I mostly agree about the advantages, but two motors would be arguably simpler from a mechanical standpoint.

One drawback that I haven't seen mentioned yet, is single-wheel torque. If you look at the video, there is a pretty sizeable motor that's even geared down with a sprocket an chain. So there is a lot of torque and power available, and due to the solid axle, you can send it to a single wheel. This might be important in off-roading situations.

With direct drive motors, you have to make a pretty big compromise somewhere:

* Two smaller motors (same total power): drastically less torque per wheel

* Two larger motors (>2x total power): somewhat less torque per wheel (still don't have gearing!), cost, weight

If you're adamant on avoiding the solid axle, I think a good-ish solution might be hub motors on all four corners. That way you're far less likely to depend on a single wheel to get you moving.

Or alternatively, a locking diff in the rear (forget about LSDs). They usually provide some gear reduction, so you can skip the chain and drive it directly with the electric motor.

In short, the solid axle is a really good choice that you would be hard pressed to replace, without making a sizeable compromise somewhere.

Yes, I might have gone for two smaller hub motors, rather than a solid rear axle. But maybe they tried that too.

Then you have two motors instead of one, and either need an ESC that handles two motors or an additional ESC, and then electronics/software to make sure they work in tandem.

Yes, I agree. I was careful to say from a mechanical standpoint.

But far more expensive. Likely the motor - possibly the batteries - is the most expensive part of the design.

Perhaps, but I don't think it would be impractical for something that's nearly $5,000 already. You would likely spec two smaller, cheaper motors; altogether it would cost more, but not as much as two of the motors it has now.

I don't doubt there's a good reason for this design, but from my armchair engineer perspective, I'm surprised he didn't go with dual hub motors on the front wheels.

My friend has a trackchair, which is basically a wheelchair with tank tracks. Slower than these bike-style chairs but very off-road capable. The coolest one I've seen is from Ziesel - their track-style chair can go 20MPH!

http://actiontrackchair.com/ https://www.ziesel-adventures.com/welcome/models

They are very cool, but the Ziesel starts at about $25,000... Not exactly comparable to this budget level machine.

Super rad. Anything to help people go places they otherwise wouldn't be able to.

That being said, I'm kinda more partial to the adaptive mountain bikes like the Sport-ONs[1]. Two wheels in front, one powered wheel in back, and a more "aggressive", sporty posture for the rider. Clearly a different market and twice the price as the Rig. It seems to me that the Rig could be a lot more comfortable and competent with some changes.

Jeremy P. McGhee[2] seems to be a reseller and booster of them.

Here's a video of him and another guy riding them along with a friend of mine (the guy on 2 wheels).

The Rig with it's capability for cargo, reminds me of an industrial bike like a Worksman[4].

[1] https://adaptivemountainbikes.com/ [2] https://www.facebook.com/jer.mcgoo [3] https://youtu.be/-IIQbD0hwto [4] https://www.worksmancycles.com

Yay for Utah (and accessibility)! I can practically see my house in some of those shots.

There is such a proliferation of new small electric vehicles like this. Is there a comprehensive catalog or list of manufacturers anywhere?

Looks really cool.

But I have to admit, I saw "not a wheelchair" and was a little disappointed that it wasn't a strandbeest chair.

They're going to sell very large numbers of these. In the same week that the SegWay is EOL'd this comes out. If 'It' had been this it would have been a damn sight more impressive. Great work, great people.

I'm actually shocked how _little_ that costs. The price for a nice entry-level Carbon Frame XCO Race bike is right around $4k. Most eMTB fall into that price bracket. That's a good deal

In the past I have looked for 4 wheel e-bike fat tire builds to find very little. This rig is in the middle of a kids barbie jeep & adult snow machine and smoother & quieter than both.

I bet it scratches at a level 6 with deeper grooves at a level 7

One trick with regular vehicles to better handle sand is to lower the tire pressure. I'm curious how well you could do on sand with bike tires using lower pressure?

But you'll run more flats with bike wheels because of how the inner tube will pull on the valve. For tubeless that's not an issue.

all they did was modify an ATV to have a wheelchair-like seat and bike wheels. The reason why wheelchairs look they way they do is so they can be accommodated in indoor environments and fit through doorways or on a bus or folded and stowed away. It is pretty cool though and I can see a disabled person finding this useful but I don't see it as a substitute for a wheelchair either.

Any idea how to start building and selling this kind of stuff? It’s my dream job. But I’m not charismatic enough to make videos.

They make rugged electric wheelchairs that sit on cat tracks. Would like to hear the pros/cons of this vs that?

Without having seen or used one, I would assume they're not as fast, not as smooth, more expensive, more difficult to repair, heavier, and potentially bulkier.

Top gear did a thing on it


If they use treads, they probably also have more traction on slippery surfaces. Having spent a lot of my life on snow, watching her go up that snowy slope made me cringe. I get she was with her husband and they recommended the buddy system, but I definitely would expect that thing doesn't just get stuck on soft snow/sand but also easily slides on harder snow and ice. Of course regular wheelchairs don't do any of that, still think this product is completely amazing. However if you lived somewhere where you were exposed to snow/ice a lot, one of the more expensive treaded options might be the right call for getting around in daily life.

Solid rear axle? DRIFT MACHINE! :-)

For those of you who haven't followed the story and seen the original reveal video: https://www.youtube.com/watch?v=H3_mVryqXpU

Shut up, I'm not crying. You're crying!

Was hoping there would be blueprints. Still really cool though

I want this. I have MS and miss hiking so very much.

Off-topic, but 3 minutes in... so beautiful.

4750USD doesn't sound extremely affordable for battery only up to 10 miles at best, so less than 5 miles one direction under ideal conditions. I dunno, I would expect at least better range from 4 wheels, simple body, suspension and electric enegine worth 4.8K. this seem like something worth max. half of the price they sell it for

I fail to see benefit compared to ATV - I just checked some shops and you can buy brand new gasoline ATV for like 3000USD, electric ATV around 5000USD. ATV will be faster, cheaper and have better range than this

ATV weighs 400 lbs and doesn't use off-the-shelf bicycle components.

This is basically a recumbent four-wheel electric light-duty fatbike. It's a niche and I think it's cool.

One could just as easily compare an electric bike to a honda ruckus.

An ATV doesn’t provide the trunk support that most wheelchair users need.

Will modifying an ATV to give trunk support not be cheaper ? it won’t be as portable though

I suppose so. I think that an ATV’s saddle style seating is less stable in general though. I’ve never ridden an ATV but it seems to me like a lot of the time rider stability is derived from the feet being planted and the quads and glutes being able to hold onto the saddle, which for paralyzed users is unlikely. In this vehicle it has an actual seat so the butt stays planted and provides the side-to-side stability.

ATVs are loud and often require use of legs to ride properly.

for price of this vehicle you can buy already electric ATV, so much for noise

Something that is not a wheelchair is the Genny. I used to work there in IT Dep. many years ago and still i think is the only real useful application of a Segway. And the best part it doesnt't look like a fucking wheelchair, when i was trying it many people stopped me and ask if they could try it. luckly for me, I'm not paraplegic so they had a ride. The only const: Is not that cheap, 20K Euro. But if don't live in a retarded country (yes US, I'm talking about you) the biggest part is on the state


> if don't live in a retarded country

Probably not the best terminology to use on a post about people with disabilities.

> Probably not the best terminology to use on a post about people with disabilities.

You've obviously never hung around with people with disabilities. "Political correctness" is not exactly their/our long suit.

One of my favorite experiences was watching a group of people with learning disabilities call each other "retard" and crack up every time.

Don't even get me started about Deaf people and the jokes they make about people that can hear when they think you're not watching.

Probably the pickiest comment i ever received

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact