I have a long term plan to fit larger tyres.
I did a spreadsheet to evaluate the differences.
Adventra Tyres Photo by routier1642 | Photobucket
There will be an issue with the speedometer reading being inaccurate. (under-reporting the speed)
This could be adjusted by Holden, but they probably wouldn't co-operate if the tyre size change isn't ADR approved.
235/60/R17 is the Ford Territory tyre size, which is what I am considering.
I'm waiting for the current tyres to wear out a bit more; I can't afford to do this on a whim.
Those tyres will make 100 km/h read as 95 km/h.
(You could always use GPS speed on a phone or tablet like I do)
You'll gain just over 17mm of radius, so measure those clearances.
The other concern is what the tyre might bump into under extreme conditions, like when you hit a big bump while moving with the wheels on full lock.
I've raised my Adventra using Kings Springs and by hacking the Auto-Levelling Suspension so it raises the rear, and thus, also the front a bit more.
Not sure how much clearance I have now, but it's a lot, more than 40mm above standard.
(The vehicle does roll a little now; it never used to at all.)
I'm counting on this additional clearance to deal with the potential impingement problem.