Just like the cars that they are modeled from, every car in iRacing a different limit to how far you can turn its ‘virtual’ wheel. At the same time the physical wheel on your desk has its own range of motion. The steering range of cars can range anywhere from 180 degrees in some open wheel cars to 900 degrees in production based cars.

Because of this, only modern 900 degree wheels are able to turn the physical wheel of all cars lock to lock without some sort of help. To fix this problem for legacy wheels we have two separate approaches. At speeds below 30 mph we just change the steering ratio so that your wheel can turn the cars wheels to their full range. This way you can navigate through pit road and turn around on the track after a spin. But at speeds above 30 miles per hour we gradually switch over to a non linear steering algorithm. This algorithm tries to keep your wheel linear (1:1) with the cars steering wheel through the first 50% of your wheels range. Then as your steering increases we begin to change your steering ratio allowing you to add in more lock while sacrificing some linearity and control over your steering. 

Without this non linearity, it would be difficult to drive many production based cars when using an older 270 or 180 degree wheel.s But not all cars need their full range especially at high speeds. In some cases you may even want to have a linear wheel with less travel instead. So we added in another adjustment, Map Range. You can find this setting on the controls tab of the options dialog. This lets you control the tradeoff between linear steering and having more lock to lock range. By default this is set to a minimum of 360 deg, or your wheels lock to lock range if it is higher, but the map range can be adjusted up to decrease the steering sensitivity, or down to increase the steering sensitivity as needed.