Sullii the 72 GMC 1500

[hewittca]

I've had a little set back with the truck this week. I drove the truck to work one day and upon walking out for the evening I was greeted with a puddle of coolant under the radiator. I was able to make it home, but the brand new Cold Case radiator was leaking from the core. Their customer service is actually quite good, however, and they are going to send me a new radiator thanks to their lifetime warranty.





While I wait on the new radiator, I figured it was a good time to clean up the garage a bit and get the truck up on stands to work on my wheels. My son was quite enthusiastic about helping me on this particular day.



The process is fairly simple for modifying the backspace of these wheels. Basically, I started by cutting the welds and knocking the centers out of the hoops so I could clean up all the old welds.





Next, I made a quick tool to press the centers in to the 5.25" backspace I wanted. When the horizontal bar reached the back of the hoop I knew I was at my desired backspace. I thought this would press in my centers squarely, but it actually wasn't as close as it needed to be. So, I made another tool for checking backspace all around the wheel mounting surface. A little tapping here and there with a hammer until this feeler gauge was even across all points on the center of the wheel.





Next, I needed to really fine tune the center of the wheel by actually measuring runout. Unfortunately, I did not have a way to spin up the wheel because I was doing all this at work. I ended up checking for variations across a flat plate set on top of the mounting surface with the wheel face down on a surface plate. Max allowable runout at the outer hoop is 0.030", so I figured under 0.010" would be good enough where I was measuring. This was achievable with a little patience and a few more taps of the hammer.





Once I was satisfied with the positioning of the center, it was simply a matter of welding them back in. All that work for 3/4" of difference!



In the end, they don't really look much different, but it bought me the extra clearance I needed so I could tuck tire on a 10" rim. My son helped me check clearance with my tire gauge stick.