If you mean a Highlander and not the Highlander edition 4Runner, you don't have enough fenderwell to go much bigger - looks like one size more is all it can take. The one out in the parking lot has 225/70R16 tires. Doesn't look like even a 235/75 would fit without some rubbing. Maybe 245/70? 245/60? 245/40? (kidding)
You can't go too big anyway - the drivetrain and chassis won't take much extra stress. The Highlander is a car, and not designed for it. (I'm not trying to badmouth it, a buddy has one and it's a very comfortable ride, but it is not an offroad vehicle - it's based on the Camry...)
Last edited by Flamedx4; 11-30-2004 at 09:57 AM.