The 1928–1931 Ford Model A SuperSlide Rear Leaf Spring for 48-1/2" – 49-1/2" Spring Perch Centers by Posies (Part #29-31R / 29-31R-S Series) is a premium transverse rear leaf spring designed specifically for stock-width Model A rear suspension setups and hot rod quick-change rear conversions. Engineered to replace stiff, original high-arch leaf packs, this spring combines traditional styling with low-friction inter-leaf technology for improved ride comfort and a lower profile.
Product Overview & Performance
Original Model A multi-leaf rear springs suffer from metal-on-metal friction, leaf binding, and harsh ride compliance. Posies overcomes this by embedding exclusive moly-nylon SuperSlide buttons between leaf tips, eliminating squeaks, binding, and rust while allowing the spring leaves to flex smoothly over road surfaces.
This stock-width series is engineered specifically for applications utilizing standard-width rear axle perches (49-1/2" center-to-center when mounted over the rear axle on 1928–1931 Model A Fords) or behind-the-axle configurations (48-1/2" center-to-center when mounted behind quick-change rear end setups on 1932–1934 Fords).
Stance & Eye Configurations
The 29-31R stock-width series is available in two distinct spring eye configurations to achieve your target rear ride height:
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29-31R (Reversed Eye): Lowers the rear chassis approximately 2" or more below original Model A ride height for an aggressive street rod rake while maintaining proper suspension travel.
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29-31R-S (Stock Eye): Restores traditional factory ride height, ideal for stock restorations or builds requiring extra rear wheel-well clearance.
Key Features & Design Highlights
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Dual Application Placement: Functions as an over-the-axle replacement for 1928–1931 Model A Fords (49.5" perch spacing) or as a behind-the-axle spring on 1932–1934 Ford quick-change rear end setups (48.5" perch spacing).
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SuperSlide Inter-Leaf Technology: Exclusive moly-nylon buttons eliminate inter-leaf friction, binding, rust, and noise.
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Custom Spring Arch & Rate: Engineered specifically for early Ford chassis weight distribution to provide a softer, more compliant ride compared to rigid factory leaf packs.
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American-Made Quality: Hand-assembled and tour-tested in the USA with over 100,000 miles of proven street rod reliability.
Product Specifications
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Manufacturer: Posies Rods & Customs
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Part Numbers: 29-31R (Stock Width / Reversed Eye / ~2"+ Drop) / 29-31R-S (Stock Width / Stock Eye / Standard Height)
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Vehicle Compatibility: 1928–1931 Ford Model A Cars & Pickups (Over-Axle) / 1932–1934 Ford Hot Rods (Behind-Axle Quick-Change)
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Suspension Type: Transverse Rear Leaf Spring
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Spring Perch Distance: 49-1/2" Center-to-Center (Over Axle) / 48-1/2" Center-to-Center (Behind Axle)
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Inter-Leaf Damping: Moly-Nylon SuperSlide Friction-Reduction Buttons
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Product Weight: Approx. 46.0–54.0 lbs
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Product Dimensions: 41" L x 17" W x 3" H
