GPBikes mods Wiki

Tyre model

We will only focus on the 3 following parameters in this section : Radius (m), TorusRadius (m) and Width (°)

You have the following input parameters : width of the tyre (W), height of the tyre based on the ratio (R) and rim size (usually 17") (Rim)

Here is a tool to easily change tyres :!oAhAlIBA!a03weRZpqIN6Se7Crpa26lZwXJRNbgz0GDlcxra4A4U  You need geogebra to iopen it (

For the moment, this info is still not confirmed, but based on reverse engineering we suppose this is the tyre model used:

><=====   : 1/2 Tyre

Other view:

\     ^
 \    | width (in °) 
  \   v 

To retrieve the width of the tyre :

  • W = Sin(Width) * TorusRadius * 2

Some technical informations about tyres : 


To limit the bike angle in GPB, you need to play with the grip parameter.

Each tyre has 3 coumpounds. Right now are 6 different Tyres available (Qualify, Soft, Softhard, HardSoft, Hard, Wet).

Usually, you have the same compound use for all 3 parts (example : soft tyre, hard tyre, ...).

The Softhard and Hardsoft tyres use different compounds on the tyre (e.g. compound 0 - soft, compound 1 - hard, compund 2 - hard). They are asymmetric tyres.

Here is the compound order:

  • c0 = left compound
  • c1 = center compound
  • c2 = right compound

Each compound has its own properties on different track surfaces (e.g. asphalt1)

  dry_grip = 0.98
  wet_grip = 0.7
  max_wet = 0.5
  curve_type = 1
  resistance_dry = 1
  resistance_wet = 3

The lean angle is based on the lateral grip the tyres can generate.

It is based on the following paramters : compound, temperature, wear, wet, grove, marbles and road banking. 

So to limit the bike angle, you have to reduce the dry (or wet) grip.