Deaver Progressive Series springs are high-quality 9-leaf and 10-leaf units fabricated with high grade 5160 “American Made” steel. A higher leaf count spring allows the use of thinner leaf material that yields a more flexible progressive leaf stack, or pyramid, producing a much smoother spring rate curve throughout the complete suspension cycle. The even, linear compression rate curve of our progressive system spring is the primary key to excellent ride quality.
 
Other designs features include full military-wrapped spring eyes for superior durability, diamond cut inner leaf ends minimizing shear points and anti-friction pads inserted between the leafs for a smoother ride and quiet operation.
Combined with properly valved shock absorbers, the ride is enhanced beyond belief.