An interesting and related story: European newspaper couriers used 6 wheeled Citroens to transport the paper across countries overnight at nearly 100 mph.
It's worth noting, that the Tissier modifications extended the hydropneumatic suspension to the extra axis. So despite being a flatbed or newspaper truck, they were still very comfortable.
I have seen a Tissier modification of a DS myself.
I mean, duh. You have to have suspension on the extra axle (well you technically don't but there would be some significant downsides to that approach) and just duplicating whatever the OEM did is the obvious way to go if practical. I'm not well versed in Citroen's hydraulic system of the era but I bet it would be only slightly more complex than adding a tag axle on airbags.
It is quite a complicated system, particularly because it was unique to Citroën. Only a few one-offs from other manufactures used the suspension system. So getting parts was not particularly easy.
Effectively, you ended up making them yourselves. You'll also need to ensure that the pump could handle the extra axle, and that there was sufficient hydraulic liquid to handle the now much larger hydraulic system. Remember the hydraulics also controlled the braking and the steering. All in the same system as the suspension.
There is good reason why a lot of heavy modifications of Citroëns of the era simply did away with the original suspension, and replaced it with bog standard suspension. It requires quite a bit of expertise to understand. It's possible, as Tissier proved. And Jerry Hathaway, who modified a Citroën SM do over 320 km/h, build a pickup out to carry it out of another SM.[0] I had the good fortune of meeting him back in 2017, and his SM.[1]
This was odd, intriguing and just down right neat. I honestly started reading and couldn't stop. It felt like every scroll would introduce me with a new way to configure an N-Wheeled car that I would have never dreamed about.
The Chrysler[0] voyager III is like someone watched the homer-mobile episode of the Simpsons[1] and thought 'you know, that's a great idea!'
[0] Technically Plymouth apparently.
[1] I thought at first that maybe the voyager III came first, since it was apparently considered the worst concept car ever, and the history behind the voyager III seems to mirror some of the history alluded to in the episode, but no, the simpsons were 1 year before plymouth, someone must seriously have heard of that episode and not thought 'this is scarily foreshadowing, maybe we should rethink'.
Totally out of context but might be of interest: Douglas Self, the site owner, is also an EE who authored some good books about audio related electronics.
Very interesting, as a motorcycle rider I am familiar with both two and three wheeled machines. Having two in the front for a three wheeler is much more stable and Can-Am produced by BRP in Canada is an example that is more more like a motorcycle while the Slingshot produced by Polaris is more like a car. The distinction I use is seating position and how you steer them. Both are a hoot to drive but I give the nod to the Can-Am for utility
There have been some one wheel motorcycles and even two wheeled motorcycles have been computerized to be self driving and self balancing, Honda made one that is stable even while not moving
Still my favorite eight, or is that twelve, wheeled vehicle is the Landmaster [1] which was produced for the movie Damnation Alley in the seventies.
I have this feeling that three-wheelers with the lone wheel at the back must be more stable. The ones with the lone wheel at the front and to the side are utterly bizzare.
I am no 'Robin Reliant' fan however they were far more stable in real life than what Jeremy Clarkson would lead you to believe. In the Top Gear show where they rolled the Robin Reliant a few times there was a lot of weight over one side of the vehicle but not the other to make it perform for the cameras.
They were stable and quite nice inside for the time. However, they came with a stigma not from being three wheeled but because they did not require the full driving license. If someone had a Robin Reliant then you knew they couldn't pass their driving test and had gone for the cheesy way out.
They weren't performance cars but they weren't the slowest cars on the roads either. I grew up in the countryside with narrow and very steep roads, there weren't a lot of these three-wheeler things but they actually were suitable for the terrain. Being lightweight helped, and, if you meet an on-coming car in a narrow lane then having the front wheel in the middle has advantages when it comes to 'tucking in'.
Anyway, I am not sure how up to date the article is as the Mercedes 6x6 version of the G-Wagen deserves to be mentioned:
In my experience with my two three wheeled go-karts, having the single wheel at the back is much more stable. I’ve never worked out exactly why that’s the case though.
It's because almost all vehicles can decelerate much faster than they can accelerate. Add to that that they may be decelerating into a corner and you can see how having a lone wheel in front is going to cause a lot more tipping over than having it in back.
The old-style three-wheelers (that they haven't been allowed to sell for decades) didn't have a differential in the back, so you had to tip them to the outside in order to turn sharply. Yes this was dangerous.
You didn't have to tip them. You just needed to get them to break traction on the inside wheel. You can do that without leaving the ground though leaving the ground is a pretty guaranteed way to accomplish that goal.
I’m not a physicist but I’m assuming because the most stable part of the chassis is at the front of the vehicle inertia is less likely to make it unstable. I’m sure, if you took those go karts in reverse to the same speed as a go kart with a single front wheel moving forward, that turning would be equally unstable.
As far as straight line stability I’m sure it has to do with being pushed vs pulled. I wonder if a FWD single-front-wheeled go kart would be more stable than a RWD single-front-wheeled go kart
The force of a turn spreads over the wide, instead of the narrow end, when you're driving towards the two wheels. You have to be more careful with trying to brake into a turn tho.
Polaris makes a "Slingshot" vehicle in that configuration, it looks like fun. From just looking at and sitting in one someone was trying to sell, I was concerned with its balance at speed. It felt light and as if it would be easy to put into an unrecoverable spin. Never got to drive it, alas.
I have this vague recollection from many years ago that the Sports Car Club of America (SCCA) had a racing class for 3 wheel vehicles that had the single wheel in the back. They were typically powered by motorcycle engines and they looked really cool!
I don't remember exactly when it happened, but I think SCCA banned all 3 wheel racing vehicles some time back. I think it was because 3 wheel vehicles with the single wheel in the front are inherently less stable. It's a shame because that class was less expensive to compete in, and the cars looked great.
Yeah just kind of recklessly scrolling through the article and the specimen in there caused me to back up and take a cloer look. Something compelling about those, definitely would like to tool around in one.
In the realm of modern human-pedaled and electric-assist tricycles (e.g. for carrying kids, passengers, cargo, etc.) the single wheel at the back configuration is called a "tadpole" and it's common and considered stable. Caveat: "stable" is relative. Example: Bicycles are unstable at rest but stable at speed, compared to any tricycle which is stable at rest but unstable at speed, particularly when turning. But plenty of fun if you're willing to lean. See also: professional motorcycle sidecar racing. :-)
Decent three-wheeler bikes have the two wheels at the front, so rather than training wheels, you have increased traction. Both of these bikes are highly rated:
It should be noted that both those three wheeled motorcycles lean while turning, making them functionally very similar to two wheeled motorcycles in operation. This makes them much more stable compared to a non-leaning three wheeler.
They are, the car is pushing "forward and to the outside" of turns. For some chuckles, here's Top Gear demonstrating the fact (over and over) https://www.youtube.com/watch?v=QQh56geU0X8
As a sibling comment mentions, the two-front, one-back configuration is out there in sport-leisure type vehicles. I think it appeals to people who want motorcycle-ish sportiness but maybe are turned off by the appearance of complete exposure or the possibility of dropping the bike.
Modern three-wheelers I'm aware of, on roughly the "car-ish <----> bike-ish" spectrum are the Campagna T-REX, the Polaris Slingshot, Can-Am Spyder, Piaggio MP3, and the Yamaha Niken. The first two are pretty "sporty car" vehicles, the latter two "complicated motorbikes", and the Spyder maybe a 40-60 mix, IMO.
I met a Reliant fanatic/dealer who supplied some of the vehicles for that and he seemed annoyed that they had put big tanks of water in the back for those shots...
I'd imagine that 24-wheel limo needing a special track just to get from A to B. That thing probably can't make a right or left turn on a typical two-lane road.
This is what the old inet was about, obsession over freaky things. Not people, not self, not money, not attention.. just obsession with that one topic.
[1] https://petrolicious.com/articles/vintage-friday-when-overni...