I would like your guys opinion...you think 305/65R18 is a good size or would you guys go bigger?

 

That's a 33" tire. You could go to a 35" with no problems.
I prefer more tire sidewall, less rim.
I would do 315/75/16 or 305/70/16.

 

I scored a brand new set of flat black 18x9 liquid metal Gatlins on eBay for $320 shipped so I'm looking for tires for them

 

18" wheels are not a great choice for off road use. For pavement they're OK if that's what you like.

 

18x9 and I have 35/12.5/18's on them, looks great with that size tire

 

18 would be the largest diameter I would go with for an H3 for on road. Personally I wouldn't go higher than the stock wheel size, and preferrably I wish we had 15's on it.

On the road you will be ok with 18's, but in my opinion anything bigger is a hazzard. If you're planning on doing any off roading the smaller diameter the wheel, the better. You want more sidewall rubber off road. I've been off roading for many years, mostly jeeps and rangers and now for the last three years with our H3. One of the reasons I was outperforming a lot of the other rigs out there is because they had big size wheels.

As far as on road with a big heavy vehicle like a H3 big diameter wheels and low profile tires are actually dangerous. In my opinion of course, but I've had first hand experience with this. Was in a bad accident with another Hummer. They lost control because of the tires and wheels. And there are a lot of warnings companies post about low profile and big wheels on rigs like ours. Just no reason for it.

 

Some h3's come from the factory with stock 18's so I don't really understand how I can be dangerous? And I'm talking about putting at least 33" tires on these things so ill still have plenty of sidewall....I'm not planning on doing any crazy off-roading so I don't see anything I'd have to worry about

 

Yeah that size is fine if you are not really doing any major off-roading. But I am with Bunger 100% on this.. More tire, more sidewall, less rim.. Looks more badazz, but that is just a personal preference.. Just post pics when you get done...