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Material Science: Foam Core and Backplane at 2026 Spec

Molded PU foam: 2.8–3.2 lb/ft³, ILD 28–34

The 2026 production run uses a high-density molded polyurethane (PU) foam core at 2.8–3.2 lb/ft³ with a 35% ILD (Indentation Load Deflection) of 28–34 lbs. That is the optimal firmness window for sustained passenger comfort through 18-hole duty cycles.

GRPP backplane replaces wood-composite boards

The rear substrate moves off legacy wood-composite boards onto a glass-reinforced polypropylene (GRPP) multi-cavity backplane. Wood wicks moisture, delaminates, and collapses the cushion — a failure techs often misdiagnose as a frame-related DTC. GRPP removes that degradation point and meets the 2026 CFFA durability mandate for non-woven-substrate coated fabrics in outdoor recreational vehicles.

DTC Mapping: When Seat Degradation Triggers Fault Codes

A seat cushion is passive and never throws a code by itself. The failure cascades mechanically: a deformed or waterlogged backplane shifts passenger weight distribution and loads E-Z-GO's rear leaf springs asymmetrically. Fleet telematics platforms (CalAmp, Lytx, Geotab) log the fallout under J1939 SPN profiles in these ranges:

• B0010–B0049: occupant classification / weight-sensor plausibility faults, if the cart carries aftermarket seat-pressure mats (fleet RXV 4 Touring).
• C0100–C0199: rear-axle speed-sensor correlation errors from uneven suspension travel under asymmetric load.
• U0100–U0299: lost communication with the body control module — seen when corroded seat fasteners cause intermittent ground-path resistance spikes on 48V DC systems.

Replace the cushion and the asymmetric loading stops — Geotab GO9, Lytx DriveCam, and CalAmp LMU-5000 series platforms typically show these intermittent codes resolved within 3–5 drive cycles.

Spec Table: Koeep vs OEM (2022) vs Generic Aftermarket

* RXV fitment applies to aftermarket flip-seat kits with the universal bolt pattern — check your flip-seat kit maker's specs before ordering. Data from OEM technical sheets, CFFA publications, and ASTM testing databases as of May 2026.

Installation and Hardware: Under 15 Minutes, No Re-Drilling

The multi-cavity backplane arrives pre-drilled for universal flip-seat bolt patterns. Bolt it on as-is and you are done in 15 minutes or less per cart. Generic aftermarket cushions average 30+ minutes because the hole pattern needs re-drilling.

Use stainless steel mounting hardware, SAE Grade 304. This matters more than it looks: corroded seat fasteners are what spike ground-path resistance on 48V DC systems and log U0100–U0299 communication codes. While the seat is off, clean every ground point and apply dielectric grease.

Refreshing the whole cabin? Pair the rear set with the Black Golf Cart Front Cushion Seat Cover for EZGO TXT so the interior wears one consistent finish, and browse the Interior Auto Parts collection for the rest of Koeep's seating and cabin accessories.

Service Life, Warranty and OEM Cross-Reference

Why the cover is bonded, not stapled

The set uses a vacuum-bonded vinyl-to-foam lamination. Bonding improves waterproofing and prevents cover separation at the stitch seams — the classic failure on stapled OEM covers after roughly 500 heat cycles. You replace the set rather than re-cover it, and the return is a projected 3–5 year service interval versus 18–24 months for re-covered OEM cushions in high-UV states (Florida, Arizona, Texas).

Part numbers and lifecycle

• Koeep Part #4831 — projected service life 2026–2030, validated through MY2030 under Textron's continued TXT-platform use for Valor, Express, and fleet trims.
• OEM cross-reference: E-Z-GO 607348 (rear seat bottom, TXT), 607349 (rear seat back, TXT), 612345 (ST Sport rear cushion assembly).
• Warranty: 5-year limited structural warranty on the GRPP backplane against delamination, cracking, and moisture-related degradation — versus the OEM plywood substrate's typical 12–18 month moisture-service ceiling in humid climates.
• Certified per production lot: Wyzenbeek beyond 100,000 double rubs (ASTM D4157); ΔE ≤ 3.0 after 1,000-hour QUV weathering (ASTM G154, Cycle 1); fungal-resistance pass per CFFA-120 / ASTM G21; horizontal burn rate ≤ 100 mm/min under SAE J369 and ISO 3795.

The same cushion set is also listed on its companion product page for the EZGO TXT, ST, ST Sport and Valor rear cushion set, and the step-by-step fitment walkthrough lives in Koeep's Complete Guide to the Black Golf Cart Rear Seat Cushion Set.

How to Check Your Model Before Ordering

Locate the serial number plate. On MY2026 models it is riveted to the passenger-side frame rail below the glove box (TXT/Valor) or inside the driver-side wheel arch (RXV). The prefix names the platform: "TXT" = TXT platform, "VAL" = Valor, "ST" = ST/ST Sport.

Running a flip seat? Measure between the outer mounting bolts on the rear seat platform. If the distance is 35.0"–37.5", the set fits — the GRPP backplane's multi-cavity design handles every common bolt pattern in that range without modification.

Fleet buyers ordering in volume: send specs through the request-for-quote page for fleet pricing. Single-cart questions go to support@koeep.com or straight to the team on WhatsApp.

FAQ: 2026 Rear Seat Troubleshooting and Fitment