Most vehicles are equipped with a splined steering shaft, allowing the driver to offset (repositioned) the steering wheel to the right or left. In the iRacing garage this is represented in plus or minus degrees. It is essentially the same as removing the steering wheel, rotating it, and snapping it back onto the steering shaft. Called steering offset, which is the amount of steering wheel rotation before re-attaching.
Mainly common in oval track racing, because the suspension is setup to make the car turn left. This make it the pull to the left, resulting in the steering wheel not being centered when driving in a straight line. Some drivers prefer to have a slight amount of steering wheel offset to the right when the car is going straight. Others may prefer the steering wheel completely centered or set slightly to the left, when going straight.
Steering wheel offset is also used in sim racing to help the vehicle get through a corner resulting in faster lap times. For qualifying try minus 6 degrees offset. On corner entry, this helps you turn the steering wheel less, allowing less tire scrub, resulting in a faster lap time. Try going no more than minus 10 degrees, but you need to experiment to match to your driving style.
Depending on the vehicle, track, conditions and driving technique most steering wheel offset settings will be range from minus 8 to plus 4. Again these are very track specific and need to be tested. Go out and run 15 -20 lap segments, then review the tire wear and lap times. Try running different offsets and see how it affects the tires and lap consistency. Remember what works for one driver may not work for another.
These adjustments may seem simple and insignificant, but these small details can make or break your race. Go to a test session, experiment with everything, and find what works best for you. Don’t just run 2 to 3 laps trying to get fast time on the board, you need to run 15 to 20 lap segments. Always check the tire wear and lap time fall off. The goal should always be consistent lap times with less tire wear.