Original: http://forum.mx-bikes.com/index.php?msg=6109

Insert into Documents\PiBoSo\MX bikes\global.ini, under [core] section ( must be created if it doesn’t exist ):

texture_quality = 4

to set the quality of loaded textures.

The possible values are:
0 -> uncompressed, OpenGL default
1 -> uncompressed, 32 bits
2 -> uncompressed, 16 bits
3 -> compressed, OpenGL driver
4 -> compressed ( the default value )

1 gives the better quality and much faster loading times, at the expense of video ram usage and a performance hit.
Please note that values from 0 to 2 are NOT recommended for multiplayer.