the replacement sagged 1'' after 75,000 miles and you think that's a bad leaf spring? that's pretty good actually, i wish the set i got would last that long (they are 4 leafs for both front and rear though so not sure how they'll work out). anyway, i'm not sure what your expectations are but there is no steel in this world that would keep it's properties indefinitely especially when it's worked out on the road for that long.
EDIT: how long after you bought them did they replace your original set? and was the 5 leaf replacement stiffer (was the back or the front that sagged or both? do you have a hardtop?)
The first set were shot in about 12 months of install and they sagged flat.
No serious activity on them at all.
I have the Hardtop, The instructions said use the 5 leaf pack on the front, which
turned out to be for the soft-top 6 cyl with winch kit and I had the 4 Cyl with hard-top.
the 4 cyl is kinda bad for sagging the rear because ti squats pretty hard when you launch it WOT.
RC took good care of me, And as far as the 1" of sag, I was not real upset about it. I had really
run it hard in the sand and knew I was stressing them. I caught some serious air..
The bushings were shot because the metal sleeve was turning in the bushing and with the sag I
popped for new springs. When you buy them without the kit they were not priced too bad.
They sent me 4 of the 5 leaf packs at my request at the first replacement, I knew my winch installation
was going to equalize the weight and the 5 packs ride better! They are just a tic thinner, so more pliable.
I was mostly trying to give a history for a daily driver that get rode hard and put up wet as the cowboy's say
Dave