Conventional Ramp Door Spring for 6' Wide Enclosed Trailer - Single Spring - 80-lb Capacity
Part Number: CB80S84S
Heavy-duty single ramp spring assembly for enclosed trailer ramp doors. This conventional torsion spring system helps you safely raise and lower trailer doors while reducing strain on hinges and supporting light-duty doors in the 40" to 67" width range.
R&P Knowledge Hub
Compatibility: Designed for enclosed trailer ramp doors from 40" to 67" wide. Commonly used on 4 foot, 5 foot, and 6 foot wide trailers depending on door setup and spring placement.
Vehicle / System Fit: Fits a single-spring ramp door system using a conventional torsion spring layout with a 150" cable.
Installation Notes: This system can be modified to fit your application by sliding the bracket and cable drum down and cutting the shaft shorter when needed. Orange safety covers install over the bolt heads to discourage unwanted adjustment.
Performance Insight: Ramp springs are selected by a combination of door width, door weight, cable length, and shaft/spring layout. Your provided information references 85 lbs or less, while the detailed spring spec lists 80 lbs capacity, so this should be treated as a light-duty application and verified before purchase.
R&P Service Insight
Ramp door spring systems usually wear out gradually from repeated loading cycles, tension loss, corrosion, and cable stress rather than one sudden event.
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Spring Fatigue: Constant opening and closing slowly reduces lift assistance over time
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Cable Wear: Long cable runs can fray or stretch, affecting smooth operation
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Hinge Protection: A properly matched spring helps reduce strain on ramp hinges and mounting hardware
Features
- Single ramp spring setup helps you lift and lower the trailer door more safely and with less effort
- Fits enclosed trailer ramp doors from 40" to 67" wide, including many 4', 5', and 6' trailer applications
- System can be modified for your installation by repositioning the bracket and cable drum and shortening the shaft if needed
- Heavy-duty steel construction with orange safety covers over bolt heads; made in the USA
Specifications
| Specification |
Detail |
| Brand |
M-3 and Associates |
| Part Number |
M364FR |
| Type |
Single ramp spring / conventional torsion spring |
| Application |
Enclosed trailer ramp door |
| Door Width Fitment |
40" to 67" wide trailer doors |
| Common Trailer Widths |
4 foot wide trailer, 5 foot wide trailer, 6 foot wide trailer |
| Overall Dimensions |
67-5/8" wide x 4-3/4" tall |
| Spring Width |
66" wide spring |
| Cable Length |
150" |
| Spring Capacity |
80 lbs |
| Door Weight Reference |
85 lbs or less |
| Material |
Steel |
| Country of Origin |
Made in the USA |
Fitment / Application
| Category |
Details |
| Vehicle / System |
Enclosed trailer ramp door spring system |
| Spring Configuration |
Single spring setup |
| Door Width Range |
Fits 40" to 67" wide doors |
| Common Trailer Sizes |
4' wide, 5' wide, and 6' wide trailers |
| Notes |
Verify door width, actual door weight, spring orientation, and cable routing before installation. This listing uses only the fitment information provided. |
Included Components
| Quantity |
Item |
| 1 |
M-3 and Associates M364FR single conventional trailer ramp spring assembly with 150" cable |
Verify all specifications, measurements, cable length, and ramp door weight before installation.
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