Physics of leaning in 2 & 3 wheeled vehicles

[strantor]

i think I've got a pretty good educated guess about why you lean a 2 wheeled bike to turn - there's a vector of force downward from gravity, and vector of force sideways from centrifugal force of the turn; these 2 vectors combine and create a vector that points down and out of the turn. You align yourself (your bike) with this vector and it's the most stable arrangement possible for cornering on a bike. please correct me if I'm wrong about this.

So, I've been tossing around ideas about making a 3 wheeled vehicle (2 front, 1 rear) and been looking at some of the designs out there. I noticed that some allow for leaning like a bike. Here's one such example. When I look at this bike, I imagine a rider on it, and imagine the down & out vector, based on where I think the center of gravity is, the vector hits the road inside the tire (mind you I'm not 100% this vector thing is even true, and I'm looking at a pencil drawing, not a simulation). So it seems to me, unless the vector hits the road outside the tire, it's pointless to lean.

In any 3 wheeled vehicle wouldn't it be better and simpler just to make the wheels far enough apart that it won't roll? or is there some other benefit to leaning that I'm not taking into account? The only added benefit I see is less side load on the wheel hub.

The 3 wheeler I'm envisioning building is more like a car than the example I linked to. an enclosed cabin, low CG, sitting position like a recumbent. highway speed capable. I can't see any reason to make it lean.

 

[TylerDurden]

http://www.jetrike.com/why-does-tilting-matter.html

 

[cal3thousand]

What about some active camber action? Like the prototype benzo:

http://www.topspeed.com/cars/mercedes/2002-mercedes-f400-carving-ar1214.html

 

[ProDigit]

You can turn, because a wheel is round, and the tire is rounded off.
Theoretically, if you have wheels with very large diameters (say 26ft instead of 26inch), and a flat tire (a square tube if that where possible, with corners, much like the rear tire of a dragster), you can lean all you want, the bike will not turn (or at least, it will not turn as much as when you have round tubes like those of a motorbike on tires the size of pocketbikes tires.

When you lean over, the front of the tire grips the floor,and in the few degrees that the tire rolls over the floor, it moves the bike upward, basically creates a vector out of the curve that the tire has, and the downward force of gravity.

Increased gravity results in increased maneuverability.