The Wheels and tires tab:

Front and rear wheels, and their several parameters are designed in this tab. A pair of radio buttons allows you to select between front and rear wheels. On the left, there are some parameters to set. Theese parameters are described below.

Repititions: Number of times the designed patern is repeated around the wheel.
Offset: Displacement of hub of the wheel from the outer side of the wheel.
Rim width: Width of the rim of the wheel.
Tread width: Width of the tread of the tire.
Tire texture material: Material for the tire texture.
Tread texture coef: A coefficient defining the boundary between tire sidewall and tire tread on the texture. A value of 0.33 means equal sidewall and tread width on the texture.
Wheel material: Material for the wheel.
Rotor diameter: Diameter of the brake rotor.
Calliper angle: Angle of the placement of the brake calliper form the horizontal line.
Calliper type: Type of the brake calliper. Possible values are 2-piston, 4-piston and 6-piston.
Calliper material: Material for the brake calliper.

On the bottom left, there is an image of the wheel showing tyre profile, rim, hub, brake rotor and brake calliper, and above it is tire cross section. This cross section can be used to visualize tire width, tread width and rim width.

On the bottom right, there is a black square with two red horizontal dotted lines. If the tire material contains a texture, this square will be loaded with the texture. You have to adjust the value of the parameter 'Tread texture coef' to align the two dotted red lines with the boundary of tire sidewall and tread on the texture.

There are two wheel design panels: one is for front view of the wheel and other is for side view of the wheel.

There is a toolbar on the left of it and an information panel on the right of it. The toolbar on the left is used to design the wheel using 'Wheel design elements'. Click here to learn more about wheel design elements. The information panel on the right shows the information about the selected wheel design item and also allows us to modify its properties.

Wheel design items can be selected by clicking them on any wheel design panel. It will appear red when selected and the information panel on the right will display its information. By holding the right 'Ctrl' key and clicking multiple items, you can select multiple items. All the selected items will appear orange and only the top selected will appear red. You can select through items by holding the right 'Shift' key while multi-selecting. This means that you can skip-out the current top selected item from selection by holding the right 'Shift' key and clicking the next item to be selected. Clicking a blank region on any panel will deselect all the selected items.

There is a '3D' button just above the wheel design panel. By clicking this button, you can see the wheel in 3D view. In the 3D view, you can rotate the wheel around vertical axis by dragging the view horizontally with mouse click.

Buttons of the toolbar and their functionality is described below.

Add wNode button : This button adds a wNode to the wheel design panels. Click this button, then click on anywhere on either wheel design panel.

Add wFace button : This button adds a wFace to the wheel design panels. Select three wNodes, then click this button to add a wFace.

Add wRing button : This button adds a wRing to the wheel design panels. Select Two wNodes, then click this button to add a wRing.

Flip wFace button : This button flips the direction the wFace is facing. All wFaces are facing towards the outer side of the wheel when added. If you need any wFace to face toward the opposite direction, flip it by selecting it and then pressing this button.

Align r button : This button align all the selected wNodes with the 'r' value of the top selected wNode.

Align l button : This button align all the selected wNodes with the 'l' value of the top selected wNode.

Align Th button : This button align all the selected wNodes with the 'Th' value of the top selected wNode.

Align vertically button : This button align all the selected wNodes vertically with top selected wNode.

Align horizontally button : This button align all the selected wNodes horizontally with top selected wNode.

Delete button : This button the top selected wheel design element. If this element is used by any other element, then it can't be deleted. For example, wNodes that are used by a wFace can't be deleted.

Save wheel button : This button saves the designed wheel to a .whl file.

Load wheel button : This button loads an already designed wheel from a .whl file.