Just as an FYI, because I've seen a couple of people mention/ask about this: no, you definitely don't need a steering wheel to enjoy ETS2. I was lazy and so hadn't set up my Driving Force GT until yesterday (had the Xbox wheel on my stand for Forza Horizon, hilariously enough) so I'd been using my PS3 controller via USB and Xinput Wrapper for a few days.
Driving with a wheel does feel better, especially when it comes to parking the truck--having that direct control over the wheel's rotation means you can respond faster to your trailer jack-knifing--but I definitely wouldn't call it a necessity. In fact, some things are a bit more difficult, like looking around the cabin. I have my camera controls hooked up to the D-pad on the wheel, but this is ludicrously impractical if you're in the middle of a tight turn and the wheel's upside down and you just need to look right but oh god the d-pad's on the other side of the wheel now and upside down and you don't even have your hand in the right spot because you're doing arm-over-arm turning and whatever I hope I don't crush a car by mistake.
So don't worry if you don't own a wheel. It's less realistic, sure, but I don't think it's any less fun or relaxing!