Steering range is the physical range of your physical wheel. Map range is the displayed range of the virtual wheel in the game.

i.e.: you set your steering range to match your physical wheel - always.. then you can play with the map range to adjust the sensitivity. the automatic adjuster that is used when you click settings will never set the map range below 360°, but you can manually adjust this by dragging the slider to match your physical steering range. Note that you can increase the sensitivity of the steering in game by increasing the map range relative to your physical range. For example: Setting your SRange to 270 and your map range to 360 can make for a pretty sensitive wheel in-game, to make it more sensitive, you could increase map range to 420. Essentially this means that for every 270° your physical wheel turns, the virtual wheel will turn 420°. Conversely, you can reduce the sensitivity by setting the map range below the steering range. Hope this helps!