Rocket Man's 2008 Bagged CC Silverado Build AKA "THE MACHINE"

[Rocket Man]

I've been trying to find out exactly what type of a setup the rear suspension is ever since I bought the truck. I'm not experienced in this. I ordered an air suspension design book about 6 months ago that's supposed to explain things but it won't ship until (finally) next week. I was told by the PO (who also didn't seem to know what it was exactly) that it's a 4-link. That much I know. But there's several types of 4-link like parallel, triangulated, etc. Plus there's different ways to keep it centered as it raises and lowers. Today, I decided that what I thought was a Watt's link isn't. IDK what it is. It's an X that connects to 4 points on the differential, 2 upper and 2 lower. It also connects to the 4-link. But I do not see how it centers the diff. It doesn't help that I'm trying to look at it by putting it on jackstands and crawling underneath it. the best pics I have are from All-Star Customs, the builder. I think it might be their own design. If anybody know what this is, please chime in. You can see the 2 upper and 2 lower links that attach to the diff, and the X-brace. I see no way to adjust side-to side unless I just unbolt the box from the frame and see if I can get it to move. I only need 1/4" to be centered.

 

[iamdub]

Best as I can tell from the pics, that X piece doesn't really do much by way of lateral bracing. For the most part, controlling of the lateral movement is all done by the bushings in that X piece and the 4 link bars. This isn't a strong design for lateral stability. It's fine if you take turns really slowly. For anything else, you need more reinforcement. Due to your tight wheel-to-fender tolerances, you're pretty much limited to a Watts. Triangulating the links would require major reconstruction. Adding a Watts would, too, but it'd be much more effective than triangulating.

 

[Rocket Man]

It corners pretty good so I’m not going to mess with the suspension at this time. The engineer at intro finally called me today and we decided they will change the backspacing by 1/2” to 3 1/4” from the 2 3/4” currently. That will put the rims at 1/8” in from where the old ones were with the 2” spacers on. Bummer is that I need to pull the tires and TPMS sensors, box them up and ship them to Cali. Good thing is that I won’t need to worry about them hitting the fenders. They said it should be a week or possibly 2 turnaround which is fast for them. It took 3-4 months to get them originally. But it’s easier than the alternates like re-narrowing the rear end or changing the suspension.

 

[Rocket Man]

Pulled the rear wheels, had the tires and TPMS removed, boxed them up and sent them via UPS today. $86 shipping for both to Cali, not bad. They said they’ll pay for return shipping. I called and talked to the engineer again to make sure he knew the centers are machined to fit the inner diameter of the raised area where the valve stems are and so they can’t be moved out on the hoops because that’s a bigger diameter like the fronts are made but being an engineer he just told me he has it handled as long as we don’t increase the backspacing by any more than 1/2” and hung up on me. Rude mofo. I suspect he is going to have them machine 1/2” from the back of the hubs since it looks to be about 2” thick there. He did say it will be quick which also makes me think that’s the plan. The process of cutting the welds that hold the centers to the hoops and then machining adapters and rewelding it would not be quick.

 

[iamdub]

Pulled the rear wheels, had the tires and TPMS removed, boxed them up and sent them via UPS today. $86 shipping for both to Cali, not bad. They said they’ll pay for return shipping. I called and talked to the engineer again to make sure he knew the centers are machined to fit the inner diameter of the raised area where the valve stems are and so they can’t be moved out on the hoops because that’s a bigger diameter like the fronts are made but being an engineer he just told me he has it handled as long as we don’t increase the backspacing by any more than 1/2” and hung up on me. Rude mofo. I suspect he is going to have them machine 1/2” from the back of the hubs since it looks to be about 2” thick there. He did say it will be quick which also makes me think that’s the plan. The process of cutting the welds that hold the centers to the hoops and then machining adapters and rewelding it would not be quick.

He's probably salty cuz he's the guy that f'ed up the original measurements.

 

[Rocket Man]

He's probably salty cuz he's the guy that f'ed up the original measurements.

Pretty sure he is the reason they’re wrong since they consulted their engineer when I ordered them because originally they said they couldn’t do 3 “ backspace but then called me back and said they could.

 

[iamdub]

Pretty sure he is the reason they’re wrong since they consulted their engineer when I ordered them because originally they said they couldn’t do 3 “ backspace but then called me back and said they could.

Said they could, yet they didn't and it's costing you more money and headache. Gotta love those in-juh-neerz.

 

[Rocket Man]

So the engineer called me last Thursday and asked if he could change backspacing by a “bit less” and I was in the process of asking him what the issue was and then he said something about being able to sell my wheels and make me new ones, then said he’d do some more measuring and call me back. So today I called the office and Shirley, who’s been helping me, said engineer dude had a family issue and wouldn’t be back until Monday and she had also heard something about new wheels but couldn’t find out anything until she heard from engineer dude. She also said that the plant knew they were a “rush” for a car show. So I wait.

 

[07Burb]

So the engineer called me last Thursday and asked if he could change backspacing by a “bit less” and I was in the process of asking him what the issue was and then he said something about being able to sell my wheels and make me new ones, then said he’d do some more measuring and call me back. So today I called the office and Shirley, who’s been helping me, said engineer dude had a family issue and wouldn’t be back until Monday and she had also heard something about new wheels but couldn’t find out anything until she heard from engineer dude. She also said that the plant knew they were a “rush” for a car show. So I wait.

Something seems fishy about “engineer dude” to me

 

[iamdub]

Something seems fishy about “engineer dude” to me

My thoughts. But, what's Mark to do?

I don't quite understand it, though. If they possibly have a buyer for the "oops" wheels and can make Mark more, then why would the offset need to be "a bit less" than what they most recently agreed on? If they're making new wheels, they can make them to whatever offset. Or am I misunderstanding something?