(For all intents and purposes, I will refer to gamepads and joysticks as simply "joysticks," hereafter.)
Officially, Scorched 3D does not support joystick input. However, where there is a will, there is a way. The workaround to getting joystick input working with Scorched is to merely have joystick commands mapped to keyboard keys.
Of course, the hardest part about this is how to go about doing it. Chances are that the software that came with your joystick supports joystick-to-keyboard commands. However, if you're in the same situation I'm in with my Sidewinder Freestyle Pro, there's no software support for newer OS's.
To get around this hurdle, you can use 3rd party software to map joystick input to keyboard keys. The one I've used is called "JoyToKey." It's free and does pretty much what I want it to, therefore, I'll be demonstrating how to use this program.
Before you get too much into doing this, it would be a good idea to make sure your joystick is in good working order with a game that utilizes joystick input commands. If the control seems a little off, you can calibrate it in the Control Panel under Gaming Options. After you've verified that your joystick is in good working order, move on to the next part of the tutorial
First, you'll need to download JoyToKey from here. Once you do that, extract it to a location and folder of your choosing and run it. Since you can make separate profiles for individual games, it would be a good idea to click on the File menu and select "Create new configuration file" and give it the name "Scorched."
After that, you can start mapping the joystick input to the keys. To do this, double-click one of the joystick button options on the right window pane and press a key that you want associated with it, keeping in mind the key layout for Scorched. Now here's where things might get a little tricky if you have a gamepad: You might have A, B, C, X, Y, Z, L, R, Mode, Start listed on your gamepad but in JoyToKey, these buttons are listed by numbers. To make things a little easier, I have provided an image of typical numerical layout of a gamepad. Be aware that some cheaper gamepads like InterAct ProPad 6 share some of the same button actions with multiple buttons.
After you have set up the mapping, leave the program open and start Scorched to test out your settings. If they aren't to your liking, you can always go back to change them.
If you have an analog control (tilt sensor/thumb stick) and find that it's too sensitive, you can turn the threshhold % up by clicking the "Others" tab on the very right side of the program.
That concludes the tutorial for mapping joystick input to keyboard keys. To give you a better idea of the program, I leave you an image of JoyToKey with my personal settings.