I've been out of the loop for quite a while, but in my outdated experience...
270° for most arcade games. Hard Drivin' & Race Drivin had 900° wheels if you feel inclined to figure out how to set them up separately.
150° or less for console games that were meant to be played with a thumbstick. The wheel can't turn as fast as a thumbstick. Dropping to a narrow range that you can move through quickly makes the games more playable.
The most important thing is reducing MAME's default 30% deadzone to something like .05 and changing the saturation to 1 (100%).
See the old stickied driving cab info thread for other settings I may be forgetting.
Thanks for the setting suggestion but I am having a problem, I set it to 270 degrees on G Hub on my MAME profile but MAME still thinks it's set to 900 degrees on my wheel.