6 Best Jack Mount Spacers For Custom Hitch Setups

Towing setups rarely align perfectly on the first try, leaving many builders struggling with jacks that bottom out or hitch couplers that bind against the frame. A well-placed jack mount spacer bridges the gap between your trailer frame and your jack, restoring the necessary clearance for sharp turns and uneven terrain. Choosing the right one transforms a frustrating installation into a seamless, reliable foundation for your mobile dwelling.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

CURT Pipe-Mount Spacer: Best Overall Value

When the goal is a reliable, no-nonsense extension for a standard pipe-mount jack, the CURT spacer is the industry benchmark. It offers a standardized bolt pattern that aligns with almost every major pipe-mount jack on the market, making it the safest bet for most trailer owners. Its structural steel construction provides consistent support without the excessive weight found in industrial-grade alternatives.

For the average DIY builder, this spacer hits the “Goldilocks zone” of pricing and durability. It lacks the bells and whistles of high-end custom kits, but it provides exactly what is needed to clear frame gussets or interference points. If the trailer frame is standard and the jack requirements are straightforward, choosing anything else is likely overspending.

Bulldog Weld-On Mount: For Heavy-Duty Use

Bulldog has long maintained a reputation for handling extreme tongue weights and high-stress environments. This weld-on mount is specifically engineered for those who aren’t afraid of a permanent installation and demand maximum structural rigidity. Because it is welded directly to the frame, it eliminates the movement and hardware fatigue common with bolt-on alternatives.

This is the correct choice for heavy-duty livestock trailers, large cargo haulers, or overlanding rigs that see constant vibration. If the trailer frame is thick-walled steel and the jack needs to endure significant lateral force, the strength of a welded Bulldog mount is unmatched. Do not consider this for aluminum-framed trailers or lightweight builds, as the welding process requires significant base material thickness.

Reese Pro Series Spacer Kit: Most Versatility

Versatility in trailer components usually means compromise, but the Reese Pro Series spacer manages to avoid that trap. Its slotted bolt hole design accommodates a wider range of hole spacing, allowing it to adapt to older trailers or non-standard custom frames. It is a problem-solver for those working with used trailers where the original mounting points might be irregular.

This kit is ideal for builders who are retrofitting a jack to a frame with pre-existing, non-standard holes. It saves the time and effort of drilling new steel, which can be difficult on hardened trailer tongues. If the project involves refurbishing an older unit, the adjustability of the Reese kit makes it a top-tier investment.

RAM Pipe Mount Kit: Easiest Bolt-On Install

The RAM Pipe Mount Kit is designed for the builder who prioritizes speed and efficiency without sacrificing safety. Its hardware package is comprehensive, meaning there is no need to scour the hardware store for the correct grade-8 bolts during the build. Everything arrives ready for a quick installation, which is a major advantage during complex mobile builds where time is always in short supply.

The fit and finish on these spacers are consistently high, reducing the need for grinding or filing during installation. It’s perfect for someone performing a solo build who needs to get the jack mounted and the trailer moving quickly. If the priority is getting the job done right the first time without complex tools, the RAM kit is the clear winner.

Fulton Spacer: Best for Marine Applications

Corrosion is the silent killer of outdoor equipment, particularly for those living near the coast or building trailers for watercraft. The Fulton spacer features a specialized coating that stands up to salt air and moisture far better than standard painted steel. It provides the same mechanical lift as other spacers but ensures that the hardware remains serviceable long after other components have rusted.

If the trailer will be dunked in water or parked in high-humidity climates, investing in a salt-resistant spacer is a matter of long-term maintenance. While the initial price is slightly higher than basic steel versions, the cost savings on replacements and seized hardware make it the only logical choice for marine-adjacent environments. This is a “set it and forget it” component.

Pro Series Universal Spacer: Top Budget Pick

For projects where the budget is tight and the structural demands are moderate, the Pro Series Universal Spacer gets the job done. It is a simple, effective piece of steel that provides the necessary lift to clear interference. While it doesn’t feature specialized coatings or complex hardware, it provides a solid mounting surface that will outlast most lightweight trailers.

This spacer is perfect for smaller utility trailers or pop-up campers where weight and budget are the primary constraints. It is an honest, functional piece of equipment that doesn’t pretend to be anything more than it is. For a basic build that doesn’t push its weight limits, this is the most economical way to achieve proper jack clearance.

Do You Really Need a Jack Mount Spacer?

A jack mount spacer is essential when your trailer tongue frame is shorter than the required clearance for your jack’s outer tube. Without this extra height, your jack handle may hit the propane tanks, your battery box, or the hitch mechanism itself. It is also vital if the trailer frame is a “C-channel” or narrow-tube style that doesn’t provide a flat, stable surface for the jack base to mount against.

Before purchasing, test the clearance by mocking up the jack position with the coupler attached to the tow vehicle. If the handle hits the frame or the jack foot drags during tight turns, a spacer is not optional—it is a safety necessity. Ignore the urge to leave the jack unmounted or to rely on a jack that is too short; both lead to compromised stability and potential trailer damage.

Measuring Your Frame and Jack for a Perfect Fit

Precision is critical when selecting a spacer, as a poor fit leads to movement, wobbling, and eventually, failure. First, measure the width and height of the trailer tongue tube to ensure the spacer footprint matches. Next, measure the distance between the existing mounting holes on your jack and compare them to the hole patterns of your selected spacer.

Do not overlook the “swing-clear” radius of the jack handle. Even if the spacer adds enough height, the jack must be able to rotate or operate without striking the trailer body or the hitch hardware. Use a piece of cardboard to mock up the jack’s footprint on the frame, and simulate a 90-degree turn to ensure the clearance is sufficient in all directions.

Weld-On vs. Bolt-On: Which Is Right for You?

Bolt-on spacers are the standard for most DIY projects because they allow for adjustment and replacement. If the jack needs to be serviced or upgraded, removing a bolt-on spacer is simple and requires only basic hand tools. However, they must be checked periodically to ensure the hardware has not loosened due to road vibration.

Weld-on spacers are superior in terms of sheer strength and are preferred for heavy-duty, high-impact applications. Once welded, the connection becomes part of the trailer chassis, offering zero movement or flex. Choose a weld-on application only if the frame material is thick enough to support it and if you are confident in your welding skills or have access to a professional technician.

Safety Checks for Your Custom Jack Mount Setup

Every custom hitch setup requires a “shake-down” period where hardware is monitored under real-world conditions. After the first 50 miles of towing, inspect the jack mount, the spacer bolts, and the jack fasteners for any signs of loosening. Use high-strength, grade-8 hardware for all bolt-on connections, and always incorporate lock washers or thread-locking fluid to prevent backing out.

Regularly clean the area around the spacer to look for hairline fractures in the paint or steel, which often indicate stress or structural fatigue. If you notice any movement at the joint, tighten the hardware immediately and evaluate if the spacer requires a gusset for additional lateral support. A well-maintained jack mount is the difference between a secure trailer and a roadside breakdown.

Selecting the right jack mount spacer is a vital step in ensuring the safety and longevity of any trailer build. By focusing on the structural requirements and environmental conditions of your setup, you can build a system that stands up to the rigors of the road. Invest in quality components now to avoid costly repairs and safety hazards down the line.

Frequently Asked Questions (FAQs)

What is a jack mount spacer on a trailer tongue?

A jack mount spacer is a rigid metal plate or block placed between a trailer tongue and the jack assembly to increase clearance or alter mounting height. Most spacers range from one-quarter inch to two inches in thickness and feature pre-drilled three-bolt triangle patterns. Fabricators use these spacers on custom utility trailers, RVs, and boat trailers to prevent the jack foot from scraping the ground or hitting weight distribution hardware during sharp turns.

What does a jack mount spacer do for a custom hitch setup?

Adding a jack mount spacer resolves clearance conflicts by raising the jack handle, gear housing, or foot pad away from vehicle tailgates and hitch components. In custom hitch setups, aftermarket accessories like extended ball mounts, sway bars, or oversize truck tailgates frequently strike the jack. Adding a one-inch spacer lifts the jack mechanism just enough to let you drop a pickup tailgate flat without denting the sheet metal or shearing off the trailer jack crank.

How do you install a jack mount spacer on an A-frame trailer?

Installing a jack mount spacer on an A-frame trailer requires unbolting the existing jack, sandwiching the spacer between the coupler and jack flange, and securing new hardware. First, support the trailer tongue securely on heavy-duty jack stands. Next, remove the three mounting bolts using a socket wrench, slide the spacer over the holes, and reinsert the jack. Always install new Grade 5 or Grade 8 bolts that are longer than the originals by the exact thickness of your spacer.

How do you measure the correct bolt hole spacing for a jack mount spacer?

Measuring a jack mount spacer involves recording the center-to-center distance between each of the three bolt holes on your trailer coupler. Use a digital caliper or standard tape measure to find the distance between the center points of adjacent holes, which typically measures three inches on standard A-frame jacks. You must also measure the inner diameter of the center collar opening, which usually needs to clear a two-and-one-quarter-inch jack outer tube.

Steel vs aluminum jack mount spacers: which is better?

Steel jack mount spacers offer superior shear strength for heavy commercial loads, while aluminum spacers provide better corrosion resistance and lighter weight for boat trailers. Powder-coated or galvanized quarter-inch carbon steel handles tongue weights over 1,500 pounds without flexing. Billet 6061-T6 aluminum spacers resist rust from road salt and saltwater immersion, making them ideal for marine haulers under 1,000 pounds of tongue weight. Choose steel for extreme utility hauling and aluminum for wet environments.

How much does a jack mount spacer cost for custom hitch setups?

Commercial jack mount spacers typically cost between $15 and $60, depending on material thickness, metal type, and included hardware. Basic stamped-steel plates measuring one-quarter inch thick sit at the lower end around $15 to $25. Thick, CNC-machined one-inch to two-inch billet aluminum blocks that include extended Grade 8 bolts and lock washers run between $45 and $60. Custom fabricated or welded drop-bracket assemblies can occasionally exceed $80.

What happens if you install the wrong size jack mount spacer?

Using the wrong size jack mount spacer can cause bolt shear, structural bending of the tongue coupler, or insufficient ground clearance when towing. If the spacer is too thin, your truck tailgate may still strike the jack housing when opened. If you use a spacer that is too thick without upgrading to longer, properly rated Grade 8 fasteners, the bolts can snap under heavy tongue vibration. A mismatched center hole will also pinch the jack tube, causing the crank to bind.

Are jack mount spacers safe to use for heavy-duty towing?

Properly rated jack mount spacers are completely safe for heavy-duty towing as long as you match the spacer material to your trailer tongue weight rating. Safety issues only occur when owners reuse original short mounting bolts or choose thin plastic or unrated metal shims. To maintain highway safety, torque three Grade 8 bolts to between 30 and 35 foot-pounds through a solid steel or billet aluminum spacer plate. Inspect the mounting bolts for tightness after the first 100 miles of towing.