I recently got around to installing Helwig 7672 and 7658 on my truck (sig). No rear bar OEM.. Increased size of front. Tires are stock (MICHELIN LTX M/S) and pressure adjusted according to scale weights and vehicle manufacturer guidelines. Bilstein shocks plus rack & pinion steering with IFS
My truck runs around at a little more than 1k above published shipping weight. That is the "adjusted empty weight" for WDH purposes. Scales show that it is near 40-lbs difference at all four corners.
With that understood then the upgrade was well worthwhile. Ruts and the like don't control it as before. Tracking is better. No question that freeway ramps, etc, are more easily handled. I run the roads at 58-mph solo or towing.
I will likely install a rear Panhard Rod (Hendersons Lineup; see Track Bar) to control body movement against the springs in crosswinds. I would also use KONI FSD shocks (same supplier; see also KONI NA website), but the 2WD IFS is not covered by that line (see discussions on Class C here).
Truck now has 200k on it and new springs, etc, are in the near future. Increased fuel tank size and the likelihood of being right on top of of tire/axle ratings when towing (fulltimer) made this experiment worthwhile. So far, so good.
I would heed BenK's reservations about increasing chance of understeer. The layman discussion of understeer/oversteer is in the book by
Fred Puhn, HOW TO MAKE YOUR CAR HANDLE. IOW, I would start with polyurethane bar bushings (ENERGY SUSPENSION; greaseable) all around plus those KONI shocks. And maximum tire pressure only adds to the problem of understeer. Get on the scale.
My latest experience of having a trailer push one around is on clay/caliche roads where the trailer weighs 55,000-lbs. Even eight drive axle tires in an offroad traction tread design is not always enough. Tail wags dog.
Good luck to all.
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