It is true that many simulators can be played with gamepads or keyboards, but these types of controllers are not ideal for simulation racing games. This is because these games are not designed to be played with gamepads or keyboards, which makes it difficult to control the car. Thus, if you want to fully experience simulation racing games, it is crucial to have a steering wheel.
When I first started playing, I used the Logitech G27. It came with pedals and a shifter. The G27 had a small motor and gears that drove the wheel. However, the wheel was quite noisy and the shifter was not great. But that was what I had at the time and I still had a lot of fun with my first wheel.
Later, I upgraded to a Thrustmaster Wheel with a larger motor and it was belt-driven. This eliminated the gear whining noise. I also got new Thrustmaster pedals and a nice shifter, the Thrustmaster TH8RS. This upgrade was a big progress for me, as it felt much more realistic, the wheel was stronger and more quiet.
Currently, I believe that buying a Direct Drive Wheel is the best option. They have no belts and no gear noise, and provide more power. The wheel sits directly on the motor shaft which means there is only one moving part.
In conclusion, to fully enjoy simulation racing games, having a good steering wheel and pedals is essential. You can start with a used one that is gear or belt-driven, but trust me, in the end, you will likely end up with a Direct Drive Wheel.