I have all steering assists off in Forza 6. But if you leave steering wheel straight it pulls hard to the left.
I can’t figure out a way to calibrate it outside of Forza 6 and doesn’t seem no adjustments in forza 6 fixes the “position” problem with the wheel. Even in game when wheel straight the guys arms/steering wheel are pulled to the left.
I have this problem as well sometimes even on Forza 5 and it doesn’t happen every time I boot up and Mine is not a software issue. Sometimes when I power up the wheel will be turned 10 degrees or so to the left which causes the car to pull to the left even when steering straight. The only cure I have found is to unplug the wheel from the console turn it all the way to the left then plug the wheel back into the console this forces the wheel to do the rotation recalibration and return to center. Hope this helps.