I'm thinking of purchasing a set of Hummer H2 wheels for my truck but I am not sure of the lug spacing required and also what dimension the center must be reamed out to. Thanks for your info.

 

It's funny -- When looking for the proper center hole size, we measured my factory wheel. umm... The center hole in the factory RAM wheel wasn't round, we found that it was more of an oval shape.

So -- The correct diameter is 4.774" You also have to trim the clips back about 1/8" on the RAM center caps and cut almost an inch off of the base of the cap. Here's a very detailed thread that helped me with mine:

http://dieselplace.com/forum/showthread.php?t=8070

 

I had mine center bored at 4.775 and it is perfect. no slop and easy to mount/dismount.