ESI Front Rail Seal XL EPDM 5.5 ft — Fits 0.488"–1" Gaps, 3M Tape Weather-Resistant

ESI Front Rail Seal XL is a 5½-foot EPDM rubber gasket that fills front-rail height gaps from 0.488" up to 1" when installing a truck cap or camper shell.

When mounting a truck cap you often face uneven rail heights between the sidewalls and the front rail. This heavy-duty extruded EPDM seal was designed to bridge taller gaps cleanly, provide a compressible, weather-resistant barrier, and stick firmly in place using industrial-grade 3M 4011 acrylic foam tape. It’s manufactured in the USA to fit common installation needs without frequent replacement after cap removal.

How does this seal solve uneven front-rail gaps?

The ESI Front Rail Seal XL compresses to fill larger height differences at the front rail so a cap or camper shell seats evenly against the truck bed rails. Its profile adds thickness where you need it most and reduces rocking or misalignment during installation.

• Designed to fill gaps from 0.488" to 1" high.
• 1.00" nominal width and 1.125" nominal height for substantial contact area.
• Extruded EPDM rubber offers resilient compression and recovery.
• Compatibility with most common cap rail geometries for simpler mounting.

Will this seal stay attached when I remove and reattach my cap?

Yes — the seal ships pre-lined with high-quality 3M 4011 acrylic foam tape for long-lasting adhesion to the truck rail. It’s formulated so the gasket remains on the rail through multiple cap removals without needing replacement each time, saving installation time.

• Factory-applied 3M 4011 tape for strong initial and lasting bond.
• EPDM compound resists creep and maintains adhesion under compression.
• Durable enough to handle repeated cap installation cycles.

How do I choose the correct ESI seal for different gap heights?

Measure the height from the sidewall to the front rail before ordering. Use the XL when the gap measures between 0.488" and 1.0". For lower gaps follow ESI’s other seal options to get the proper compression and fit.

• Gaps .488"–1.00" use Front Rail Seal XL (this product).
• Gaps .251"–.487" should use the standard Front Rail Seal (different SKU).
• Gaps ≤.250" typically require ESI single-rail EPDM seals on all three rails instead.

What are the material and dimensional specs I should know?

This seal is extruded from EPDM rubber for UV, ozone and weather resistance and measures approximately 1.00" wide by 1.125" tall in cross-section. The kit length is 5.5 feet — long enough for most full-size truck front rails or trimable to fit.

• Material: EPDM rubber, weather-resistant formulation.
• Cross-section: ~1.00" width × ~1.125" height.
• Length: 5.5 feet (trim to size as needed).
• Pre-applied 3M 4011 acrylic foam tape for attachment.

Who this product is for: This Front Rail Seal XL is aimed at truck owners, RV and camper shell installers, and fabricators who need a durable, compressible solution for taller front-rail gaps. If you measure a height difference from about 0.488" up to 1.0" between your sidewalls and front rail and want a U.S.-made EPDM gasket that adheres reliably and endures repeated cap removal, this product is a practical choice.