I don’t see them being referenced anywhere except AnimateSprocketOrIdler function and you don’t have to call it if you don’t have them, so it’s fine to remove them.
Replacing it with road wheels won’t really work as first of all they don’t have collision. The other issue is Normal Force necessary for friction, is calculated from Suspension Force, in case when your Sprocket/Drivewheel tries to go over some higher than wheel radius vertical obstacle, suspension will be pushing wheel vertically but collision surface normal would be horizontal - normal of the surface would be orthogonal to suspension so normal force would be zero or just too small to provide any kind of grip.
You could try setting suspension with 45 degrees in pitch, to get some force pushing against the wall, but most likely it will push vehicle away from the wall if force is too strong or don’t provide enough grip if it’s too little.
The real solution to all this is refactoring code to support friction in arbitrary points, effected or not effected by suspension, like it’s done on Mark-I.