You know it when you see it – some trucks are just plain ol' cool! In this case, we explore what it takes to make a classic hot rod truck handle a little better, but more importantly, not ride like a bulldozer. To diagnose the bad road manners we have to look at the truck itself. It's a 1955 Chevy truck with the typical IFS frontend that rides OK, but as you read further you will know why.
The frontend, believe it or not, reacts to the rear suspension especially when the rear suspension is too stiff or has little to no travel. Case in point is the 1955 Chevy we tested. As we went around a normal corner, the frontend would show signs of bumpsteer and react really strange at times; bias-ply tires didn't help.
The owner Matt Colvin couldn't pinpoint why the truck didn't ride as nice as he liked, so he drove the truck over to a friend's shop to check it out. Matt ended up taking his pride and joy to Strategic Racing Designs of Vista, California, to take a look at the truck. SRD is a fabrication shop that specializes in off-road race trucks, buggies, and hot rods.
One thing Justin Herrmann, owner of SRD, noticed was the lack in travel the rear suspension had. The truck had a total of 3 inches of travel in the rear, 1 inch upward and the rest was down travel. What the lack of travel told Justin and Matt was as the truck turned or hit a bump it would bottom out the rear end. This caused the frontend to react because the rear suspension was no longer suspension. In a nutshell, the rear suspension showed its ugly head when Matt put any kind of weight in the truck, thus giving even less up travel.
So to fix the truck we could've simply installed a larger C-notch, but then Matt would still have had a stiff-riding spring rear suspension. So we took a look at RideTech's universal four-bar rear suspension kit and a set of single adjustable rear coilovers. The RideTech coilovers are the key to this installation because they make adjusting the suspension simple and have adjustment for rebound.
01. What you are looking at is the truck's rearend and the C-notch gap. The gap between the rear end and the C-notch is very minimal and would not allow the rear suspension to compress when hitting small bumps.
02. Here is the second issue that we ran into. The rear shocks were leaned too far in to do any dampening.
03. Now look at the shock when the suspension is compressed. Notice that the shock comes extremely close to the rear brake lines.
04. Here is another look at the rear shock angle with the rear suspension mid travel.
05. So the first task was to put the truck on jackstands and level the frame.
06. We removed the bed so that removing the stock spring mounts would be easier.
07. The rearend was measured from the cab to the center of the axle. This gives a baseline of where the axle is before the rear springs are removed.
08. Justin also used a drop center and a piece of tape to mark the axle centerline on the ground. This helps when trying to center the rearend under the new RideTech four-bar setup.
09. After the rear springs are removed we used a grinder with a cutoff wheel on the stock spring mounts. We cut off all the rivet heads and pried off the stock spring brackets.
10. Then moving to the passenger side, we cut the rest of the spring perches off.
11. We welded the crossmember to the frame because we removed most of the rivets that held it in to get the spring perch off.
12. Justin measures the C-notch using a long-angle finder. He will then transfer the measurements to his plasma cam to make a new C-notch out of 3⁄16 plate.
13. Justin's plasma cam is a huge timesaver because it is controlled by a PC and will cut out perfect pieces every time. No grinding slag or trying to perfectly match pieces. A hand grinder, plasma cutter, or jigsaw will also work to cut out a custom C-notch.
14. A quick test fit with one of the new C-notch pieces and Justin was happy with the fitment.
15. The old C-notch was cut out so that Justin could start welding in the new C-notch. We also cut off the old spring mounts on the axle housing so that the new RideTech brackets would fit.