Second gen Tracker or Vitara/Grand Vitara - Trackers take 15" rims, Grand Vitaras & most Vitaras take 16s.
I've never seen a guide, but it's my understanding that the largest you can go on a GV with stock rims and suspension is a 235/70R16 - it may rub on the plastic underguard in front of the front wheels, which I'm told can be fixed by bending the support tab...
There are not a lot of aftermarket rim choices that clear the front brake calipers.