Welcome to the forum.
Hmmwv rims have a big offset to them for clearing the geared hubs. You have to cut the center piece out of the rim and weld it back in at the correct offset.
Make sure to balance the rim by use of welding and grinding afterwards before repainting the rims before mounting tires or you will n ver get them to ride right.
There are several shops around the country that sell them already done.
I run 12 bolt mt on my hummer and if I could in a while way afford some 17" rims instead of running he 16.5, I would. Tire selection sucks. Way more $ for same tire when you do find them. Military take offs are cheap, but dont last long becuse of dry rot issues.
DO NOT run the 36 or 37" tall tires in the 16.5 without the runflats. When there is a blowout or sudden lows of air in the tire at highway speeds, a roll over is almost always the result if ni runflat is in there. Too much sidewall deflection.
You will have to do all the tire changes yourself, shops will not touch the 2 piece rims. Balancing them needs to be done at a semi tire shop- most tire shops cant do that big and heavy (150 lbs) of a tire combo.
Invest in centrimatics or balance masters.
Also beef the crud out of your steering components- that much weight is going to break things- ask how I know- haha.
Maybe give Tom Cepek a call at GT Custom.
1-949-394-1578. He is he go to guy for hmmwv, hummer rim and tire questions. He might hwve a good sorce on the modded rims, or maybe makes a 17" you will like which will save you tons of hassle and $ long term.
