As with most others around here, my center caps for my American Racing rims wouldn't fit because of the hub centric design of the factory wheels. The AR caps are supposed to go on from behind when you mount the wheel. This just won’t work for us.
This lip is the problem:
So what to do? I went to work on them with my dremel tool and cut the lip off. I removed the rubber band and used its channel to guide/cut the lip off.
The plastic will melt a little and give you some build up. This is easily chipped off by hand or you can use some sand paper or other means.
A test fit on the wheels instantly proved that they fit. They were snug, but would most likely come flying off at speed, so I decided to put the rubber band back on.
I built up my dremel tool’s width with three cutting disks. I am sure there is a tool out there that would do this cleaner and better, but I have a “problem solving brain” so I went with the dremel method.
I cut a new channel into the cap all the way around about .5 cm in. You will have to cut the channel pretty deep to seat the rubber band deep enough to get the cap wedged into the wheel, more on this later. If you cut too deep don’t worry, it doesn’t have to be perfect. If your OCD kicks, take your meds, and you will be fine. It will take some slow work and finding the right technique, but eventually you will figure out how to groove the channel. I figured it out on the last one!
Like the first cut, the plastic melts and builds up. Most can be removed with your hand, but I used a brush from my dremel set to clear the channel away.
Put the rubber band back on and approach your vehicle slowly! Mine seems to be wary about sticking things in unused holes.
You will have to initially work them in by hand until the rubber band is all the way in the wheel, then I needed a mallet/dead blow to get them all the way seated. Be careful and start slowly. Some lubrication might be needed, but I managed to get them on without it. I would caution someone to use anything that wouldn’t evaporate because you probably don’t want these coming out because of a lubricant. Maybe try some saliva? Work the mallet around the edges, the middle of the cap is covered with a thin metal logo piece that will bend and come of if you hit it (experience speaking here). Just work the mallet around the edges until it is seated all the way back in the hole.
I have had them on the vehicle for several weeks, just haven’t had time to write this up. I checked them ever so often and they haven’t budged a mm. Sorry I will post pics of them on the vehicle later, my camera phone just doesn’t cut it.
Hope this helps everyone out with this problem.
Dax
07 TM A/T 4x4 
Linear Mode
