Thread: 4-Bar Help

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Originally Posted by rcs72

I did send the side view pic to Scott's and they said it is fine mounting the coil over tilted back 20 degrees. They did tell me to cycle it to make sure theres is no binding. They have a lot of pics on there site with coil overs but none that really show if the coil over is tilted to the back. I really hope once it's installed it doesn't ride like sh*t.

The coilovers themselves and the angle that they're mounted at won't make the truck ride like s***, but the hard connections with no compliant material to absorb road and powertrain shock may be a different story.

Go ahead and put it together and run it. If you like it, keep it. If not, put the truck up for sale and move on to another project. I think you probably know what NOT to do by now.

I can't tell from your photo, but it appears that your mocked-up rear axle has a pretty severe upward pinion angle. At ride height, the trans should be 3*down, and the pinion 3* up.

I also noticed that most of their applications placed the 4-bars inside the frame rail instead of outside. Are you OK with tire clearance, wheel backspace, etc? Was there a particular reason you set it up on the outside of the frame?

By the way, the reason that 4-bars are usually equal length an parallel is so that the axle moves up and down in a straight line. If they're not parallel, the rear axle tends to rotate about a point where a line drawn through the two bars meets in space. Of course, ladder bars work the same way, so it's probably not significant in this case.

I have NEVER seen a shock tilted backwards. I don't think it will cause a problem, but it gives the suspension a very odd look.

Pinion is at 2.5 degrees up. Should I try remounting the front bracket at an angle to try to get the coil over more vertical? I mounted on the outside of frame to get better handling. I have plenty of clearance for the wheels I will be running.

Originally Posted by rcs72

Pinion is at 2.5 degrees up. Should I try remounting the front bracket at an angle to try to get the coil over more vertical? I mounted on the outside of frame to get better handling. I have plenty of clearance for the wheels I will be running.

I wouldn't. If you angle the front bracket, you increase the angle between the bars. I don't think it's worth the effort.

I would try to make sure that the bolt going through the top of the shock is parallel with the one on the bottom. Since the shock eyes are going to pivot axially back and forth on the bolts rather than radially around them, that's your best way to avoid any bind at max suspension travel.

Posted by Jack:
"I would try to make sure that the bolt going through the top of the shock is parallel with the one on the bottom. Since the shock eyes are going to pivot axially back and forth on the bolts rather than radially around them, that's your best way to avoid any bind at max suspension travel."

Wow Jack, you've pointed out a disaster waiting to happen that I didn't see. The mounting bolts are in a bending load as the angle of the shock changes in bump and droop. It won't take long for something to break, either a shock eye or a bolt. The mounting bolts need to be rotated 90 degrees. Am I seeing this correctly?

Richard,

Maybe. I went out and looked at my coil-overs, and the shock eyes have a pioting ball which should take up any bending load without binding. However, that ball is designed to take up minor misalignments - not act as the main pivot point. I don't particularlly care for the design, but I don't think it will break anything - assuming those shocks have the same pivot ball that mine do. If the shocks have a urethane bushing instead of a pivot ball, I'd exercise the suspension travel and see what happens. I'd also be less confident in using shocks with bushings.