If removing a leaf or more from a spring pack, how does the choice of removing a longer vs a shorter leaf effect the spring pack? Which makes the most difference in the ride, spring pack sag, etc?
Trial and error. I typically start from the top removing the odd numbered springs. ( every other from the pack) until it sits where I want it
When I asked about it years ago, the local spring shop told me to start with the short ones and remove every other one. Mine was a standard '37 Chevy truck rear spring with nine leafs, I went down to five, leaving the two longest ones. It helped the ride, I now have custom made ones from Detroit Spring that work better.
on my '47 Ford coupe with stock front spring pack, & V8, I found that height lowered 1/2" for each leaf removed started by leaving top short leaf, then as stated before, every other leaf. tried aftermarket mono-leaf with limited results. be sure to consider tire clearance. can have springs modified by having reversed eye & dearched. short gas shocks for rear of 60's Corvette helped the ride.
Depending on your axle set up the leafs dont just control height and stiffnes but also lateral stability, roll stiffness and axle tramp. Sag also depends on the spring arch.
Like with most things, moderation! Depending on the spring and lengths, the very shortest ones only come into play when the spring is compressed a great degree. If you look on some sorings you can even see clearance in the short leafs with no load. So removing them would have little effect on an unloaded vehicle. I would start with the mid leafs. But remember not all leaf spring systems are designed exactly alike! Trial and error on your spring will give you the ride you desire! Bones
I've removed leafs from a spring pack many times and always start with the shortest first. My little Austin gasser rode like a buckboard with the original 5 leaf front spring pack. I'm down to the two longest spring leafs now to get the ride where it's nice. It dropped the front stance maybe 1.5" after removing the other 3 leafs.
I am personally a fan of keeping the bottom most short spring in tact. It may seem pointless to have it there, and I doubt it affects spring rate much unless you are bottomed out. What it does do is add stability to the whole pack, forcing the above springs to flex over their entire length rather than just in the middle, which is the point of the most leverage. Remove too many short leaves and your whole pack can go W or S shaped under long term use and abuse. Factory bottom leaf, main leaf (ideally mostly supported underneath) and then even spacing all the way down the pack should work pretty good for most applications. Break out the tape measure and chop saw.
Don't get carried away with removing leaves or you end up with one like mine. This was a quick and nasty lowering job to take the truck to two events in 1989 that ended up being driven almost daily for 15 years because life got in the way.
Most of the early Chev pickups dropped by pulling leaves around here broke at the back of the main leaf sooner or later.
People don't consider how their suspension will work when removing leafs from spring packs. They usually only consider compression, and not rebound. Start taking out the longer leafs and you'll find out your car doesn't rebound as slowly as it used to, and will have a lot of body roll in corners from not having those longer leafs that help control rebound.
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