Initial mock-up revealed that...
Initial mock-up revealed that the edge of our bumpstop mounting plate was going to cross through the middle of a factory frame hole. We needed to plate over the hole. To maximize strength, we decided to plate the frame top to bottom behind the bumpstop. Just as before, chipboard made a fine template.
We’ve used our Swag Off Road...
We’ve used our Swag Off Road benchtop mounting system and Milwaukee portable band saw extensively, and this combo came through for us once again.
The frame contours in our...
The frame contours in our chosen location, so we made the doubler plate match the contours using a ballpeen hammer, a short section of railroad track (used for an anvil), and a bench vise.
This photo shows the doubler...
This photo shows the doubler plate welded on. After our earlier measurements, we found that a machinist’s 1-2-3 block (rotated to the 3-inch position) was an ideal spacer to hold the axle-to-frame distance we needed.
We tried unsuccessfully to...
We tried unsuccessfully to bend the base plate to match the frame contour. To close up the gap between the flat plate and the contoured frame, we welded a skinny strip onto the base plate.
The Synergy strike plates...
The Synergy strike plates are built from 1/4-inch-thick mild steel, and are cut and formed for three-inch axle tubes. Sanding a chamfer into the ends adapted the strike plates for the 3-1/4-inch axle tubes on our custom Currie Fab-9. The middle of the Synergy strike plates should touch the tops of the axle tubes.
We spent some time getting the bumpstop and strike plate into ideal positions before tacking them in place. The goal is to minimize lateral scrubbing between the bumpstop’s contact tip and the axle strike pad as much as possible. Considering all the different angles the axle will cycle and articulate, lateral scrubbing can’t be completely eliminated, so minimization is the goal. The bumpstop’s angle is roughly 90 degrees to the lower suspension links at full compression, and the strike pad is 90 degrees to the bumpstop’s body.
One bumpstop mount, fully...
One bumpstop mount, fully welded. This shows the driver’s side; a mirror image was created on the passenger’s side.
The strike pad is easy to...
The strike pad is easy to weld on. One weld goes across each end, and a short bead is laid on each side at the top of the axle tube.
Our Kartek nitrogen regulator...
Our Kartek nitrogen regulator was pressed into service, putting 200 psi inside the bumpstop.
Check out the generous distance...
Check out the generous distance between the bumpstop and the tire’s sidewall.
An easy place to mount the...
An easy place to mount the bumpstops would have been to place them inside the coil springs, but this mounting position has been known to bend axlehousings. Bumpstops generate a lot of bending load so they should be placed as close as practical to the outer end of the axle.
We’re articulating through...
We’re articulating through a deep rut here. If we’d gone with a 4-inch bumpstop stroke we’d have less articulation, and we’d have bumpstops that frequently contacted the strike pads even over minor hits. The bumpstops have nylon contact tips, and you can hear them when they hit the strike pads. Shorter-travel suspensions should use shorter-travel bumpstops.
The markings show that lateral scrub is indeed minimal. This is what we were hoping for.