If you want to test how it works you can download and try this apk: https://www.dropbox.com/s/heev4ovn416mnk0/steering%20wheel%20test%20for%20unity%20asset%20store.apk?dl=0

This asset will provide you with virtual steering wheel that is very easy to setup and use.

How to use it?
– Drag and drop “steering wheel.prefab“ from “Prefab” folder into you canvas
– Inside your scripts call SteeringWheel.axis static variable to get steering wheel input axis.
As simple as that!

Also there is additional options that you can adjust. Please take a look at assets screenshots to see that options.