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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 utter

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.

mveety 8y ago
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.
- duncan-donuts 8y ago
  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
- Zigurd 8y ago
  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.
  - jessaustin 8y ago
    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.
    - dsfyu404ed 8y ago
      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.
- h2odragon 8y ago
  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.
inetsee 8y ago
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.
- JKCalhoun 8y ago
  And of course Jay Leno has a Morgan 3-wheeler. Man, I would love that car: https://youtu.be/2xcITHevPrc?t=348 https://youtu.be/2xcITHevPrc?t=348
  - jcims 8y ago
    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.
JWLong 8y ago
You'd be right. Reliant Robin: https://youtu.be/8KjdfuYanbQ?t=36 https://youtu.be/8KjdfuYanbQ?t=36 Slingshot: https://youtu.be/1FNO3BlyHEc https://youtu.be/1FNO3BlyHEc
patrickyeon 8y ago
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 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.
- LeoPanthera 8y ago
  Worth pointing out that the Top Gear segment was faked, with differently sized wheels and weights in the door to "encourage" the car to roll.
  - bdsa 8y ago
    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...
peteretep 8y ago
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: https://en.wikipedia.org/wiki/Yamaha_Tricity https://en.wikipedia.org/wiki/Yamaha_Tricity https://www.revzilla.com/common-tread/2018-yamaha-niken-first-ride https://www.revzilla.com/common-tread/2018-yamaha-niken-firs...
- jalgos_eminator 8y ago
  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.
  - kevin_thibedeau 8y ago
    They're more stable until you broach their lean angle limit.
    - leaning-on-lean 8y ago
      Which is basically like saying, I dunno, nothing? There’s realllllly no such thing as a “lean angle limit” for two or three wheeled vehicles. Certainly not a simple number for one angle. You can whip out the definition of a limit within the context of calculus, but such pedantry is, uh, shall we say, silly. https://en.wikipedia.org/wiki/Wall_of_death https://en.wikipedia.org/wiki/Wall_of_death Tire pressure, tire type, vehicle weight, road surface, weather conditions, velocity, driver experience level... For most people, the lean angle limit is 90 degrees, perfectly upright, at 5 miles an hour or less.
- gdrift 8y ago
  I think Piaggio were the first with a modern two front wheels scooter in 2006. They also had a hybrid plugin model doing 0-60 in 5 seconds (2008). https://en.wikipedia.org/wiki/Piaggio_MP3 https://en.wikipedia.org/wiki/Piaggio_MP3
emptybits 8y ago
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. :-)
Theodores 8y ago
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: https://en.wikipedia.org/wiki/Mercedes-Benz_G63_AMG_6x6 https://en.wikipedia.org/wiki/Mercedes-Benz_G63_AMG_6x6
mannykannot 8y ago
I wonder if 3-wheelers with the lone wheel at the back are prone to oversteer on hard cornering?
- westmeal 8y ago
  Probably, there's less of a contact patch on the surface. Although I guess it depends on the width of your tire in the rear.

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.

mveety 8y ago

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.

duncan-donuts 8y ago
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
Zigurd 8y ago
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.
- jessaustin 8y ago
  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.
  - dsfyu404ed 8y ago
    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.
h2odragon 8y ago
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.

inetsee 8y ago

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.

JKCalhoun 8y ago
And of course Jay Leno has a Morgan 3-wheeler. Man, I would love that car: https://youtu.be/2xcITHevPrc?t=348 https://youtu.be/2xcITHevPrc?t=348
- jcims 8y ago
  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.

JWLong 8y ago

You'd be right. Reliant Robin: https://youtu.be/8KjdfuYanbQ?t=36 https://youtu.be/8KjdfuYanbQ?t=36 Slingshot: https://youtu.be/1FNO3BlyHEc https://youtu.be/1FNO3BlyHEc

patrickyeon 8y ago

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 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.

LeoPanthera 8y ago
Worth pointing out that the Top Gear segment was faked, with differently sized wheels and weights in the door to "encourage" the car to roll.
- bdsa 8y ago
  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...

peteretep 8y ago

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: https://en.wikipedia.org/wiki/Yamaha_Tricity https://en.wikipedia.org/wiki/Yamaha_Tricity https://www.revzilla.com/common-tread/2018-yamaha-niken-first-ride https://www.revzilla.com/common-tread/2018-yamaha-niken-firs...

jalgos_eminator 8y ago
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.
- kevin_thibedeau 8y ago
  They're more stable until you broach their lean angle limit.
  - leaning-on-lean 8y ago
    Which is basically like saying, I dunno, nothing? There’s realllllly no such thing as a “lean angle limit” for two or three wheeled vehicles. Certainly not a simple number for one angle. You can whip out the definition of a limit within the context of calculus, but such pedantry is, uh, shall we say, silly. https://en.wikipedia.org/wiki/Wall_of_death https://en.wikipedia.org/wiki/Wall_of_death Tire pressure, tire type, vehicle weight, road surface, weather conditions, velocity, driver experience level... For most people, the lean angle limit is 90 degrees, perfectly upright, at 5 miles an hour or less.
gdrift 8y ago
I think Piaggio were the first with a modern two front wheels scooter in 2006. They also had a hybrid plugin model doing 0-60 in 5 seconds (2008). https://en.wikipedia.org/wiki/Piaggio_MP3 https://en.wikipedia.org/wiki/Piaggio_MP3

emptybits 8y ago

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. :-)

Theodores 8y ago

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: https://en.wikipedia.org/wiki/Mercedes-Benz_G63_AMG_6x6 https://en.wikipedia.org/wiki/Mercedes-Benz_G63_AMG_6x6

mannykannot 8y ago

I wonder if 3-wheelers with the lone wheel at the back are prone to oversteer on hard cornering?

westmeal 8y ago
Probably, there's less of a contact patch on the surface. Although I guess it depends on the width of your tire in the rear.