[Sausager]

I have been thinking a bit recently about leaf springs in general, and I have some questions.

How are things like ride quality, spring flex, longevity, axle wrap, etc etc influenced by the following spring traits: Steel type/yield/properties, steel thickness, #of leaves in pack, leaf width, spring length, arch size/shape?

What works well in a Zuk?

What steel are the factory Zuk springs made of?

Cheers

[just_cruizin]

Steel type your not going to have a choice on, though there is a lot of variation on quality. Thickness and width vary the spring rate in proportion with the second moment of area of the cross section. The number and length of the spring vary the rate, the shorter the spring the later the become involved in the spring deflection and therefore increase the spring rate. The longer the spring the more mechanical advantage, same as using a breaker bar on a ratchet. The greater the arch generally the stiffer they are are due to the angle of the shackle relative to the spring. The smaller the angle the smoother the ride. That's why a flat spring with the shackle angle of about 70 degrees is very smooth. A 3" lift spring with a vertical shackle are very stiff and rough ride.

What works well in zook works well in every vehicle a flat spring with a shackle angle of slightly less than 90 degrees

[MrRocky]

Spring length and shackle angle are biggest influences on ride and flex in my experience. For terrain i drive in wa running only 3 springs always seems to result in spring snaps. Up front i ran 4 springs passenger side and 5 drivers side to combat the sierra sag/lean

[Gwagensteve]

Young's modulus for spring steel is pretty consistent. Sure, you could organise a tensile test on a sample leaf to confirm, but the range of possible answers is pretty small.

Most of your questions will be answered by playing with a leaf spring rate calculator.

For reference, stock sierra leaves are 220lb/" rate front and 150lb/" rear.