Limiting caster and steering lock to realistic ranges is easy, as you can just cap the minimum and maximum values. Gear ratios are not so easy, as we already have bounds caps, and merely allowing only 2 decimal places precision is no better than 3. So what's the solution, to have a huge table of realistic values? OK having just a few available sets for the road cars is fine, but not for F1 with their custom made gearboxes. Some will try and argue that they can't just switch gear ratios every two laps, but the same could be said of most settings. Then there is the issue of how to store this information in the setup, atm it's stored as the raw ratio (stored to 4dp), so any setup editing applications could just put back this flexibility unless extra checks were involved and the setup re-limited upon usage.