I have a 2008 GU6 with the 17inch factory alloys and 265/70/R17's (31inch)
I am looking for a 33inch equivalent.
It looks like a new 16x8 sunny with 285/75/R16's seems to be a well used combo and will be cheaper than the rubber alone on 17's.
Good so far?

The tyre shop tells be they recommend a -23 offset on the 16's.
I believe my current offset is +10.
Is offset mm? And if so, why would a 33mm change be needed for an increase from 265 to 285. Surely i only need to change 10mm and therefore a 0 offset. Or are brakes a factor?

Just checking - a positive moves the inside rim nearer the engine and a negative moves away from the engine. Right?

Thanks.