What Kind of Wheel Can I Use on my Hummer ?
Updated July 19, 2016
This article is not a how to on wheel and tire maintenance. I started writing it when I received an email asking what the inside scoop was on Hummer wheels. This is my take on the subject.
The factory one-piece steel wheels are hub-centric, and use the flanged lug nuts. All other wheels, are lug-centric and use the "acorn" lug nuts. What this means is that the one-piece factory wheel depends on it's fit over the hub for centering and support. Because of this the hub hole in a one piece wheel (4-3/4") is about 1/32" in diameter smaller then the other Hummer wheels.
The size of the lug nuts is 9/16-18. The nuts that hold the halves together on a military 2 piece 12 bolt wheel are ½” – 20 locking Flange Nuts. I believe these are stover design locking nuts.
The earlier Hummer 2 piece wheels had pentagon nuts which required a special factory socket. They did this because the legal dept at AMG felt it was dangerous for customers to be able to take apart a 2 - piece wheel. The military wheels used normal hex nuts. I replaced all the nuts on my wheels with military nuts.
The correct way to measure the width of a wheel is from bead seat to bead seat.
Another important factor in wheel maintenance is lug nut torque. See the article on mounting and balancing wheels.
Because New aluminum wheels have some crush value left in them they should be retorqued at 50, 100 and 200 miles. After that they should hold their torque.
Another question that gets asked a lot is how shinny can you polish an aluminum wheel? Cepek says that you can only get them to a certain level due to the amount of porosity in the material / castings. Once you reach a certain point the harder you try the worse they look.
All the Hummer H1 wheels use a standard 8 bolt x 6.5" pattern found on Chevy and older Ford trucks. This doesn't mean that you can use just any wheel on your Hummer. Wheel load capacity is most important. It would be pretty devastating if a wheel cracked in half as you were driving down the highway at 65mph. A Hummer is much heavier then most trucks, especially loaded with accessories and requires a wheel that can stand up to the weight and off-road abuse. My stock 98 wagon weighs 8000. The factory 2 piece steel wheel is rated at 3,400 pounds. The Cepek 17" aluminum wheel is rated at 4,500 pounds. Most owners don't realize that the stress and strain on the truck is much more on the road due to the speed of the truck. Hitting a bump off the road at 2 or 3 mph is much less stressful than hitting a pothole at 30 mph or the constant punishment of driving at 60+ mph.
All H1 Hummer wheels have a 7" backset. Backset is the distance from the back of the wheel to the inner edge hub contact plane of the wheel. Several issues stem from changing the offset. One is clearance between the inside of the wheel and the suspension parts / geared hub. Another has to do with loading of the hub bearing. If you change the location of the tire you change forces on the spindle of the geared hub. The first thing you're going to notice if you have the wrong offset is that the tires are sticking out beyond the wheel wells. You will get road dirt, snow and slush kicked up all over the sides of your truck. An extreme example of what not to do are those customized 'low riders' with their wheels sticking way out beyond the body. If your wheel is cantilevered out way beyond its' design limit it acts as a big lever, multiplying all the forces acting on the hub. Changing the backset also changes where the center line of the wheel will be in relation to the steering and suspension geometry. This effects alignment which in turn will effect handling and tire wear.
Offset is the distance from the actual center of the wheel measured from flange to flange to the mounting surface. A + offset moves the wheel closer to the vehicle. All the Hummer wheels have a + offset because of the large backset. For instance a Cepek 17 x 9 wheel has a +50mm offset.
The third issue with aftermarket wheels is the location of the air valve hole. You will need custome CTI lines to make this work. If the hole in the rim for the wheel fitting isn't pointing up towards the center you will have problems fitting CTI lines to the wheel.
There are only 2 companies making proper wheels for the H1; AM General and GT / Cepek.