# B2.WheelJoint

Supported platforms:
Available since: Gideros 2011.6
Inherits from: b2.Joint

### Description

A wheel joint provides two degrees of freedom: translation along an axis fixed in bodyA and rotation in the plane. You can use a joint limit to restrict the range of motion and a joint motor to drive the rotation or to model rotational friction. This joint is designed for vehicle suspensions.

### Examples

Wheel joint

```--create empty box2d body for joint
local ground = world:createBody({})
ground:setPosition(350, 480)

--axisx, axisy values usually between 0 and 1
--0 0 moves freely
--0 1 force pulling back on y axis
--1 0 force pulling back on x axis
--1 1 force pulling back all diretions
local jointDef = b2.createWheelJointDef(body, ground, 350, 200, 1, 1)
local wheelJoint = world:createJoint(jointDef)
```

### Methods

b2.WheelJoint:enableMotor enables or disables the joint motor
b2.WheelJoint:getJointSpeed returns the current joint translation speed in meters per second.
b2.WheelJoint:getJointTranslation returns the current joint translation in meters.
b2.WheelJoint:getMaxMotorTorque returns the maximum motor torque in N*m
b2.WheelJoint:getMotorSpeed returns the motor speed in radians per second
b2.WheelJoint:getSpringDampingRatio returns the spring damping ratio
b2.WheelJoint:getSpringFrequencyHz returns the spring frequency in Hertz
b2.WheelJoint:isMotorEnabled is the joint motor enabled?
b2.WheelJoint:setMaxMotorTorque sets the maximum motor torque in N*m
b2.WheelJoint:setMotorSpeed sets the motor speed in radians per second
b2.WheelJoint:setSpringDampingRatio sets the spring damping ratio
b2.WheelJoint:setSpringFrequencyHz sets the spring frequency in Hertz (0 = disable the spring)