Different tyre sizes on my Colorado 2014

Im sure there will be threads on here about this , and if so, please mention it. Just wanting some comment from experienced operators re the tolerance of differnt trye sizes on a rig. For eg. A 225/75 16 has the same diameter within 3 mm as a 245/70 16 .
I have a set of 225/75 AT on at present but have a couple of 245/70 with about 30% left on them that will fit my colorado 2014 but also all these rims and tyres fit my offroad boat trailer as well.

Yep. So my key question is what kind of tolerance is there in such situations in operating in 4wd and 2wd ?
cheers and thanks in advance.

It would want to be an extremely forgiving surface (sand/mud) before I tried running different sized tyres on any 4wd, much less a brand new one. For the money involved vs the cost of possible damage I would think 4 new tyres might be in order.

There is an Australian standard as to how much bigger a tyre can be for particular size tyre , my old foes had an unusual size tyre and bob jane s bought up the standard on the computer and sold me a better suited tyre . I would talk to a tyre specialist but yes there is some room to move on size I'm just don't know how much for your application...Matt

Ive got four tyres the same size
just trying to get the spare right