(Editing as of 2/13/22):
PSA for anyone who plays the few great motorcycle games on Naomi/Model 2&3: If you happen to have the PS2 version of the Thrustmaster Freestyler Bike, it
WILL work with arcade stuff with very little modification, but if for any godforsaken reason you plan to open the controller up and take it apart, you need to be EXTREMELY careful!! There is very narrow space between the wires, the main handle of the controller, and mechanisms. I had moments where the brake spring flew right off even on the 2nd attempt. It would be excellent if someone brave enough would make a teardown video of the controller if one was planning to replace the pots once they start to go bad.
Anyways, to wire up the Thrustmaster you need to do the following:
1.) There are a total of 4 screws you will need to get out with a standard Phillipshead screwdriver. Take the two screws on the back of the silver body, which hold the main bar assembly. When you pull those bars out, you will have to unscrew the two tall screws from where the legs where, to gain access to the motherboard and all the connectors.
2.) Unhook all the connectors from the motherboard. Both handlebar grips have their own connectors, so you can plug Dupont cables directly into them to get your controls working without cutting any of the cables off, which I strongly don't recommend for such rare controller.
3a.) Each wire is color-coded differently but in a unique fashion. For the left handlebar grip, I only wired the Triangle & Square buttons for shift-up and shift down on games like Harley-Davidson LA Riders because I'm a lefty and prefer playing manual transmission in that game.
-
Triangle (use for Shift Up) = Yellow
- Square (use for Shift Down) = Orange
(^ worst case scenario they are swapped)
- Ground (digital inputs) = Two tied brown wires
3b.) For the right handlebar grip I wired these buttons:
-
R1 (I use this for Start but you can wire it however you'd like) = Grey
- Gas/brake VCC = White
- Gas/brake GND = Black wire with white stripe. It is on a tied connection with another black wire used for another ground. If you want to swap +5V and GND to pots I STRONGLY recommend cutting the other ground off so you do not short anything by accident.
- Gas signal = Yellow with black stripes
- Brake signal = Orange with black stripes
- Circle (I use for H-D Music Selection) = Red
- X (Use for H-D View Change) = Orange
- Ground (digital inputs) = same as on 3a
3c.) There is additionally a 4-pin JST SM connector for the main handlebar that also goes to one of the motherboard connectors, with two signals for the "GP" and "Cross" modes. Luckily I had some more of those connectors lying around already to fashion.
My Thrustmaster Freestyler Bike and connectors are soldered to a DB15 cable and works great but I haven't wired the LEDs yet. On Model 2A Manx TT Superbike, the GP pot is too sensitive and the game does not have manual calibration in the menus. I reckon it would be perfect for the Sega JVS-based bike games like Wild Riders and Harley King of the Road using the S-JIHP.

Just take major caution if you DO take this wheel apart and can get the brakes and gas to spring back in place.