Finding a truck cap, also known as a truck topper or camper shell, can significantly enhance the functionality of your pickup. They provide secure storage, weather protection, and even transform your truck bed into a temporary sleeping space. However, before you rush to buy a used cap – especially one you already have from a previous truck – it's crucial to understand the compatibility factors involved. This article focuses on the question: What other trucks will a cap fit that came off a 1990 Chevrolet short box regular cab truck? We'll delve into the intricacies of bed dimensions, generation similarities, and key considerations to ensure a proper and secure fit.
Why Bed Cap Compatibility Matters
Will That Old Cap Still Fit? Finding the Right Truck Bed for Your 1990 Chevy Short Box Cap
A properly fitting truck cap is essential for several reasons:
- Weather Protection: A secure fit prevents rain, snow, and debris from entering the truck bed, protecting cargo and preventing rust.
- Security: A well-fitted cap provides a barrier against theft, keeping your tools and equipment safe.
- Aesthetics: An ill-fitting cap looks awkward and detracts from the overall appearance of the truck.
- Structural Integrity: Gaps or improper mounting can stress the cap's structure, leading to cracks and damage over time.
- Safety: A loose cap can be a safety hazard, potentially detaching during driving.
Understanding the 1990 Chevrolet Short Box Regular Cab Dimensions
The foundation for determining compatibility lies in understanding the dimensions of the 1990 Chevrolet short box. This generation of Chevrolet/GMC trucks (1988-1998, known as the "GMT400" platform) had a standardized short bed size. While minor variations can occur, the approximate inner bed dimensions for a short box are:
- Length: 78.7 inches (6.56 feet)
- Width: Approximately 60 inches (5 feet) at its widest point. This measurement is usually taken between the inner wheel wells.
- Bed Rail Height: This is a critical, and often overlooked, measurement. It's the distance from the bed floor to the top of the bed rails. These heights can vary slightly, so a precise measurement is vital.
Key Factors Determining Cap Compatibility
Beyond the overall bed dimensions, several other factors contribute to compatibility:
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Generation and Body Style:
- GMT400 (1988-1998 Chevrolet/GMC): This is the most crucial factor. Caps designed for short bed, regular cab trucks within this generation have the highest probability of fitting. Minor adjustments might be necessary, but the overall fit should be close. This includes Chevrolet C/K 1500, 2500, and 3500 series, as well as GMC Sierra 1500, 2500, and 3500 series, provided they are regular cab, short bed models.
- Regular Cab vs. Extended/Crew Cab: A cap designed for a regular cab short bed truck will not fit an extended cab or crew cab truck, even if they have a "short bed." The cab shape and the resulting bed dimensions differ significantly.
- Bed Style (Fleetside/Stepside): Most caps are designed for fleetside (smooth-sided) beds. They will not fit stepside (fenders outside the bed) models. The 1990 Chevy typically came with a fleetside bed.
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Bed Rail Design:
- Shape and Contour: Even within the GMT400 generation, subtle variations in the bed rail design can exist. Caps are often designed to conform to the specific curvature of the bed rails for a snug, weatherproof seal.
- Top Rail Width: The width of the bed rail itself can impact how the cap sits. If the cap's clamping mechanism is designed for a narrower rail, it may not secure properly to a wider rail.
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Clamping Mechanisms:
- Type and Location: Caps use various clamping mechanisms to attach to the bed rails. These clamps need to align correctly with the underside of the bed rails for a secure hold. The location and design of these clamps are crucial for compatibility.
- Condition: Inspect the clamps for rust, damage, or missing hardware. Replacing or repairing these components may be necessary.
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Rear Window and Tailgate Compatibility:
- Seal and Overlap: The rear window of the cap should align properly with the tailgate to create a weatherproof seal. Gaps or misalignment can lead to water leaks and dust intrusion.
- Tailgate Design: Different tailgate designs can impact the fit of the cap's rear window. Minor adjustments to the cap's seal or tailgate may be required.
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Bed Liner or Rail Caps:
- Thickness and Interference: Bed liners and rail caps add thickness to the bed rails, which can interfere with the cap's fit. You may need to remove or modify these accessories for proper cap installation.
Trucks with a High Probability of Compatibility (Within the GMT400 Generation - 1988-1998):
- Chevrolet C1500 Regular Cab Short Bed (1988-1998)
- Chevrolet K1500 Regular Cab Short Bed (1988-1998)
- Chevrolet C2500 Regular Cab Short Bed (1988-1998)
- Chevrolet K2500 Regular Cab Short Bed (1988-1998)
- GMC Sierra 1500 Regular Cab Short Bed (1988-1998)
- GMC Sierra K1500 Regular Cab Short Bed (1988-1998)
- GMC Sierra 2500 Regular Cab Short Bed (1988-1998)
- GMC Sierra K2500 Regular Cab Short Bed (1988-1998)
Trucks with a Low Probability of Compatibility:
- Any truck outside the GMT400 generation (1988-1998).
- Any extended cab or crew cab truck, regardless of bed length.
- Any stepside (fenders outside the bed) truck.
- Trucks with significantly different bed rail heights or designs.
- Ford or Dodge trucks - their bed dimensions and rail designs are completely different.
Steps to Determine Compatibility:
- Measure Your Truck Bed: Accurately measure the inside length and width of your truck bed. Compare these measurements to the dimensions of the 1990 Chevy short box (approximately 78.7 inches long and 60 inches wide).
- Compare Bed Rail Design: Carefully examine the bed rail design of your truck and compare it to the design of the 1990 Chevy. Look for similarities in shape, contour, and width.
- Inspect the Clamping Mechanisms: Ensure that the cap's clamping mechanisms are compatible with the underside of your truck's bed rails. Check for proper alignment and secure attachment.
- Test Fit (If Possible): The best way to determine compatibility is to physically test fit the cap on your truck. This allows you to assess the overall fit, seal, and clamping mechanisms.
- Consult a Professional: If you're unsure about compatibility, consult a truck accessory specialist or a truck cap dealer. They can provide expert advice and assistance.
Potential Challenges and Solutions:
- Minor Fit Discrepancies: Even within the GMT400 generation, minor fit discrepancies can occur. These can often be addressed with shims, weather stripping, or slight adjustments to the clamping mechanisms.
- Bed Liner Interference: Remove or modify the bed liner or rail caps to ensure a proper cap fit.
- Damaged Clamps: Replace or repair damaged clamping mechanisms to ensure a secure attachment.
- Water Leaks: Install new weather stripping or sealants to prevent water leaks around the cap's perimeter and rear window.
Table: Compatibility of 1990 Chevy Short Box Regular Cab Cap
| Truck Model | Generation/Years | Bed Type | Cab Type | Fit Probability | Notes |
|---|---|---|---|---|---|
| Chevrolet C1500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| Chevrolet K1500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| Chevrolet C2500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| Chevrolet K2500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| GMC Sierra 1500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| GMC Sierra K1500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| GMC Sierra 2500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| GMC Sierra K2500 Short Bed | GMT400 (1988-1998) | Fleetside | Regular Cab | High | Best chance of direct fit. Minor adjustments may be needed. |
| Chevrolet/GMC 1500/2500/3500 - Extended Cab | GMT400 (1988-1998) | Fleetside | Extended Cab | Low | Will NOT fit. Cab shape and bed dimensions are different. |
| Chevrolet/GMC 1500/2500/3500 - Crew Cab | GMT400 (1988-1998) | Fleetside | Crew Cab | Low | Will NOT fit. Cab shape and bed dimensions are different. |
| Ford F-150 Short Bed | Any | Fleetside | Regular Cab | Very Low | Will NOT fit. Different manufacturer, completely different bed dimensions and rail design. |
| Dodge Ram 1500 Short Bed | Any | Fleetside | Regular Cab | Very Low | Will NOT fit. Different manufacturer, completely different bed dimensions and rail design. |
| Any Truck - Stepside Bed | Any | Stepside | Any | Very Low | Will NOT fit. Caps are designed for fleetside beds. |
| Any Truck - Outside GMT400 (1988-1998) | Any | Fleetside | Regular Cab | Very Low | Extremely unlikely to fit due to different bed dimensions and rail designs. |
Frequently Asked Questions (FAQ)
- Q: Can I make a cap fit if it's slightly too small?
- A: It's very difficult and generally not recommended to make a cap fit if it's too small. Stretching or modifying the cap can compromise its structural integrity and lead to leaks.
- Q: Can I make a cap fit if it's slightly too big?
- A: Minor gaps can sometimes be addressed with shims and weather stripping. However, if the cap is significantly too large, it's unlikely to fit properly.
- Q: Where can I find the exact bed dimensions for my truck?
- A: You can find bed dimensions in your truck's owner's manual, online truck forums, or by contacting a truck accessory dealer.
- Q: Are all short beds the same size?
- A: No. While some generations have standardized short bed sizes, different manufacturers and generations have varying dimensions.
- Q: What if my truck has a spray-in bed liner?
- A: Spray-in bed liners typically don't add enough thickness to significantly interfere with the cap's fit. However, it's always best to check for proper clearance.
Conclusion
Determining whether a cap from a 1990 Chevrolet short box regular cab truck will fit another truck requires careful consideration of bed dimensions, bed rail design, clamping mechanisms, and other factors. While trucks within the GMT400 generation (1988-1998) have the highest probability of compatibility, it's essential to measure and test fit the cap before making a purchase. By following the steps outlined in this guide, you can increase your chances of finding a cap that fits properly, providing secure storage, weather protection, and enhancing the overall functionality of your truck. Remember, a well-fitting cap is an investment that will protect your cargo and add value to your vehicle.
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