Trailer Tongue Jack: Types, Weight Ratings, and How to Choose the Right One

Key Takeaways

• Size your jack to at least 125% of your trailer's tongue weight
• A-frame jacks bolt on in 30 minutes — the most common type for bumper-pull trailers
• Electric jacks cost $150-$400 but eliminate manual cranking
• Swivel jacks fold horizontal while towing to prevent ground strikes
• Grease the inner tube every 3-6 months — rust seizure is the #1 failure mode

The tongue jack does one job — raise and lower the front of your trailer for hitching and unhitching — but it's one of the most-used components on any trailer. A jack that's undersized, seized from rust, or poorly mounted turns a 5-minute hitch-up into a 30-minute ordeal. Understanding tongue weight, jack types, and weight ratings helps you pick the right jack the first time and maintain it so it works every time you need it.

Before choosing a jack, know your trailer's tongue weight — it determines the minimum weight rating you need.

Tongue jacks come in four main types, each designed for different trailer sizes and use cases. The mounting style and trailer design dictate which type fits.

Source: Bulldog, Lippert Components, Curt Manufacturing specifications

A-Frame jacks mount to the trailer's A-frame tongue with two bolts. The tube extends straight down and cranks with a top-mounted handle. This is the most common type on travel trailers, enclosed cargo trailers, and larger boat trailers. They're simple, strong, and the easiest to replace.

Swivel jacks pivot at the mounting point. When hitched, you swing the jack up and horizontal so it rides above the ground. When unhitched, swing it down and crank to support the tongue. Swivel jacks prevent the jack foot from dragging on the ground or catching on obstacles while towing — a common problem with fixed A-frame jacks that don't retract high enough.

Side-wind jacks mount to a vertical pipe welded to the trailer tongue rather than bolting to an A-frame. The crank handle sits on the side rather than the top. These are common on heavy-duty utility trailers and car haulers that use a pipe-style tongue instead of an A-frame.

Pro Tip: If your A-frame jack drags on driveways or speed bumps while towing, switch to a swivel jack or add a removable caster wheel to the foot pad. A dragging jack wears down the foot, damages driveways, and can catch on road imperfections at speed.

Undersizing a tongue jack is the most common mistake trailer owners make. A jack rated at exactly your tongue weight is already at 100% capacity — one soft spot in the ground and the jack fails or bends.

The formula: Tongue Weight × 1.25 = Minimum Jack Rating

Your trailer's tongue weight is typically 10-15% of the Gross Trailer Weight (GTW). Here's how that scales:

Source: Industry standard tongue weight calculations, RVIA guidelines

The pin weight for fifth-wheel trailers is different — it's 15-25% of GTW and requires a much heavier landing gear system rather than a tongue jack. This guide covers conventional bumper-pull trailers only.

Measure, don't estimate. Tongue weight changes based on how you load the trailer. A trailer loaded with heavy items at the rear can shift from 12% tongue weight to 7% — or vice versa with forward-heavy loading. Use a tongue weight scale or take your loaded trailer to a truck scale for an accurate number.

Common Mistake: Using a 1,000 lb jack on a 7,000 lb travel trailer because "it came with the trailer." Factory jacks are often undersized to save costs. A loaded travel trailer can easily exceed 1,000 lbs of tongue weight when water tanks, propane, and gear are added. Upgrade to at least a 2,000 lb rated jack.

Electric tongue jacks use a 12V DC motor to extend and retract the jack tube at the push of a button or flip of a switch. No cranking, no effort, no sore arms after lifting 800 lbs of tongue weight.

When electric is worth it:

• Tongue weight over 500 lbs (cranking gets old fast)
• Frequent hitching and unhitching (weekend campers, boat launchers)
• Physical limitations that make cranking difficult
• Travel trailers with slide-outs that change tongue weight when deployed

When manual is fine:

• Light trailers under 3,000 lbs with low tongue weight
• Occasional use (a few times per year)
• Budget-conscious builds where $150-$400 matters
• Situations where 12V power isn't readily available

Electric jacks draw power from the trailer battery or the 7-pin connector's 12V auxiliary circuit. Most draw 25-35 amps during operation, so ensure your trailer battery can handle the load. A dead trailer battery means your electric jack won't work — always carry a manual backup crank or a small jump pack.

Top electric tongue jack brands include Bulldog (the industry standard), Lippert (common on new RVs), and Husky. Prices range from $150 for basic 2,000 lb models to $400 for 3,500 lb units with LED work lights and built-in level indicators.

Key Insight: Many electric jacks include an override handle socket that lets you crank manually if the motor dies. Check that your model has this feature before you buy — a motor failure at a remote campsite without manual override means you can't unhitch.

Installing or replacing an A-frame tongue jack takes about 30 minutes with basic hand tools. Electric jacks add another 15-30 minutes for wiring.

For A-Frame manual jacks:

1. Remove the old jack. Support the trailer tongue on a stable block or jack stand. Remove the two mounting bolts securing the old jack to the A-frame. These are typically 1/2" or 9/16" bolts.

2. Position the new jack. Slide the new jack's mounting bracket over the A-frame. Align the bolt holes. If the holes don't match (different brands use different patterns), drill new holes using the jack's bracket as a template. Use a step drill bit on thin A-frame walls.

3. Install mounting hardware. Use Grade 5 or Grade 8 bolts with lock washers and nylock nuts. Torque to the manufacturer's specification — typically 30-40 ft-lbs for 1/2" bolts. Do not use standard nuts without lock washers — vibration will loosen them.

4. Test the jack. Crank it fully extended and fully retracted. Check for smooth operation and any binding. Apply marine-grade grease to the inner tube before first use.

For electric jacks, add these steps:

5. Mount the jack using the same A-frame bolt pattern as manual jacks.

6. Run the power wires. Connect the positive (red) wire to the trailer battery or 12V auxiliary circuit through a 40-amp inline fuse. Connect the negative (black) wire to the trailer frame ground.

7. Mount the switch or remote inside the tongue tool box or on the A-frame where it's accessible.

8. Test both directions. Run the jack fully up and fully down. Listen for unusual motor sounds. Check current draw if possible — a healthy motor draws 25-35 amps under load.

Pro Tip: Before removing the old jack, mark its position on the A-frame with a paint pen. This gives you a reference point if the new jack has a slightly different footprint. Also measure the old jack's extended height — your new jack needs to lift the coupler at least to ball height on your tow vehicle.

Tongue jacks fail from rust, not from mechanical wear. The inner tube slides inside the outer housing, and any moisture that gets between them starts corroding within weeks. Regular maintenance prevents the most common failure: a seized jack that won't crank up or down.

Every 3-6 months (or before each towing season):

• Fully extend the jack and wipe down the inner tube
• Apply a thin coat of marine-grade grease (not WD-40 — it's a solvent, not a lubricant)
• Check the foot pad for cracks or missing rubber
• Inspect mounting bolts for tightness — re-torque if loose
• Test the crank handle for smooth operation through full range

For electric jacks, additionally:

• Check all wiring connections for corrosion
• Test the motor in both directions with no load
• Inspect the motor housing for water intrusion
• Clean battery terminals if connected to trailer battery
• Verify the inline fuse hasn't corroded

Replace the jack if: the inner tube is visibly bent (common from hitting objects while towing), the gears strip and skip under load, the outer housing has structural cracks, or rust has seized the tube despite lubrication attempts.

Store your trailer with the tongue jack retracted and the coupler on a block. A fully extended jack sitting in standing water for months is the fastest path to a seized tube. If you must store with the jack extended, cover the tube with a jack cover or PVC pipe sleeve.

Common Mistake: Using WD-40 as a lubricant on the tongue jack tube. WD-40 displaces water initially but evaporates and leaves no lasting lubrication film. Marine-grade grease or white lithium grease stays in place and provides long-term protection against rust and binding. Apply it with a rag along the full length of the inner tube.