Simple answer is 4 springs supporting 4000 pountds, or 1000#/spring. 1000/220 = 4.5" of compression of the spring from it's relaxed state.

Longer answer is that leaf springs are progressive, the spring rate increases as more and more of the leaves are brought into play. Also different weights on front and rear axles, etc.

I checked the spring rate of my rear Alcan/AOR springs and get about 180 lb/in., just measure the ride height before and after loading the back up with 600 lbs. of steel. I get abut 1.7" of sag with that weight.

r.c.brown@ieee.org
TruckEditor@tlca.org
Project: 4Crawler
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