Terracraft Trike Leaning Into A Corner

Does Leaning A Trike Into Corners Make It Handle Better?

The short answer is, “Yes”.  It makes the trike handle a lot better (as leaning does to a motorbike and as it would to a four wheel car) because it changes the position of the vehicles centre of mass and counteracts the centripetal force a vehicle experiences during cornering.  See the video below to see how it works.

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If We Dont Lean A Vehicle What Happens?

Without leaning a vehicle over into the corner what we are basically left with is our ability to maintian traction.  When a car or motorbike comes into a corner, the forward momentum wants to keep going forward.  So when we turn the steering into the corner we feel the vehicle resist and try to keep going in a straight line.  This resistance is Centripetal force and left to itself it will try to flip the vehicle over. So without leaning the vehicle we are left with only one thing between us and flipping, traction of the tyres.


How Traction Helps Vehicles Stay On The Road

Scorpian P6 Trike Cornering

      Scorpian P6 Trike Cornering

Traction is made up of several components all working together.  These are:

  • Type of tyre compound (is the tyre hard or soft?)  Soft has more grip.
  • Condition of tyres (are the tyres looked after or have they been abused?)  
  • Age of tyres (tyres go off after a set age)
  • Type of road surface (very smooth concrete, rough bitumen or dirt?)
  • Condition of road surface (is it filled with potholes or in good condition?)
  • Is it dry or wet?
  • Finally, how much weight is on them.  More weight equals better grip (to a point.)

So all of these things work together to determine how much traction we have between the vehicle and the road.  In dry conditions a tyre will normally grip up to 1.1 lateral G Forces. And in the wet it will grip up to 0.9 lateral G Forces.  After those thresholds are met the vehicle will start to slide outwards with the centripetal force and in the worst case, flip over.  

So what most designers do to make the vehicle stick to the road and resist sliding or flipping over is widen the track (the distance between the two wheels on the axle) or lengthen the wheelbase the distance between the front and rear axles.


The Delta Trike With No Leaning

The Delta Trike, (one wheel forward and two wheels back) I think, can be the best looking shape as it often ends up looking like a jet fighter.  And who among us would not like to be jumping into our very own jet fighter each morning and powering off to work of flying two feet above the ground on the weekends?

Vigilante TriVette II Trike top

     Vigilante TriVette II Trike Top

Vigilante Trivette 11 Trike Front

     Vigilante Trivette 11 Trike Front

But the Delta configuration has a serious problem that the Tadpole trike does not.  It has to get all its steering from a single front wheel and so without leaning the trike into corners, the center of mass shifts outwards and breaks away early. 

So most designers just end up making these ridiculously long wheelbase vehicles that make a Jaguar XJS bonnet look short.  Personally I think they are working with the wrong design just for looks and engineering out the problems where they could start with the better base idea (Tadpole) and produce a magnificent driving machine.


The Number Two Reason To Lean A Trike Into Corners

If the number one reason is “Better Handling” then the number two reason is “Feel”.  Leaning into a corner is just a natural reaction. In a car with four wheels, as you turn you fall outward of the turn and end up pressed against the side of the car throughout the turn.  In a race car, your seat is made to hug you close, so this feeling is minimised but in a normal car it can be quite unnerving as you slide out of you seat.

When you lean a vehicle into the corner like a motorcycle, you take all that uncomfortable force that would be trying to though you outwards of the turn, and let it push you down, more securely into your seat.  The very force you were once fighting is now helping you be more comfortable driving through the corner AND shifting the center of mass to help the tyres maintain as much traction as they can.

As a pilot, (small, single engine only) I can attest that the BEST feeling is turning in a small plane.  As the whole plane banks into the turn you just get pressed more into you seat. It is a wonderful feeling and frankly I believe that every vehicle should employ it.


Different types of leaning

To keep the reading of this article simple I will refer only to a Delta Trike here.  Just swap it around if you want to apply it to a Tadpole Trike.


Fixed Rear Leaning Trike

There are three different ways to lean a vehicle over.  The first is what I call a “Fixed Rear”.  This is where the two wheels at the rear stay square to the ground (are fixed) and the whole body of the vehicle, including the single front wheel, rotates around the centre of gravity.

Carver Delta Trike Front

      Carver Delta Trike Front

Carver Delta Trike Top

       Carver Delta Trike Top

This Fixed system keeps a lot of the weight low, between the duel wheels and still provides a good sense of motion as the body compartment is moving in tune with the cornering.  This allows you to minimise the G Forces you will feel from fast cornering and be more aligned with the vehicle.  One downside of this system is that is uses a motor to move the body around.  Obviously if that motor experiences a problem or the computer managing it, then your leaning trike just became a non-leaning one and inherited all the problems of non-leaning trikes.


Body Only Leaning Trike

Next we have the “Body Only” Lean System.  So in this case, all three wheels stay flat on the ground but the body roll allowed is rotate around the center of gravity therefore shifting the mass.  I have never seen one of these made but the theory seems ok to my eyes. In both the above cases I think that this approach is smart from a building perspective but cheating on the end result.  They seem to be compromisers to me.

Narrow Track Trike Body Leaning

     Narrow Track Trike Body Leaning Image

Narrow Track Trike Body Leaning Model

     Narrow Track Trike Body Leaning Model


Complete Leaning Trike

The next system is the “Complete lean”.  It incorporates all of the car including all three wheels (so even the wheels themselves lean over).  So in unison, the whole trike leans over into the corner. By doing this it helps increase the threshold that the trike breaks traction and makes the cornering ride so much more comfortable and enjoyable.  This truly is as close to flying near the ground as you can get it.

There are purely mechanical systems for leaning a trike.  I am investigating them and will add them in here when I know more.

So there you go.  For me, it has to lean into the corners.  I want to be flying a two feet off the ground.  I want to be as close to a motorcycles flying feeling while still maintaining a car's safety.  And that can easily be done in Trike.

Tell me what you think.  Which lean system suits you the best.

Cheers.

About the Author Jonathan

Hello, I am Jonathan, a lover of vehicles that spark the imagination, make your blood boil and take you to a place where time stops and the moment is everything. Hence my love of trikes.

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