How to weigh a travel trailer at a CAT scale

A CAT scale is where your truck's and trailer's printed ratings turn into measured pounds. The brochure tells you a GVWR, a payload and a tow rating; the scale tells you what your rig actually weighs once the water tank is full and the gear is aboard. The whole job is two drive-throughs and some subtraction, plus a bars-released reading if you tow with a weight-distribution hitch, and this guide walks each step on one illustrative rig so every figure reconciles. Reading the printed ticket line by line is a separate skill, and tuning a weight-distribution hitch is another again. Both are named where they come up, and both are covered in their own US guide: reading the printed ticket and tuning a weight-distribution hitch.

How do you weigh a travel trailer at a CAT scale?

Weigh the rig coupled in one drive-through that reads every axle group at once, then weigh the truck on its own after you have unhitched off the scale. If you tow with a weight-distribution hitch, add a coupled reading with the spring bars released, arranged with the scale operator: tongue weight is that truck weight minus the truck alone. A CAT scale has three side-by-side platforms, so unlike a single-pad scale it captures the steer axle, the drive axle and the trailer axle in one motion. That is the step people search for, so here it is as a list you can follow at the pump island.

1. Load the rig travel-ready (full fuel, water as you carry it, gear, passengers and pets aboard) because an empty weigh hides the numbers that matter.
2. Pull onto the scale coupled and set up the way you tow, with your steer (front) axle on platform 1, your drive (rear) axle on platform 2 and your trailer axle on platform 3.
3. Start the weigh: push the button on the intercom sign and a cashier takes your information, or do it from your phone with the Weigh My Truck app.
4. If you tow with a weight-distribution hitch, tongue weight needs a coupled reading with the spring bars released. Arrange it with the scale operator in a safe area, following your truck and hitch instructions. Take the reading with the tongue jack fully retracted and the full tongue weight supported by the hitch. Do not drive with required weight distribution disabled to get a number; if your setup needs the bars to move, measure the tongue with a tongue-weight scale or a professional weighing service instead. Re-tension the bars to their setting before the rig moves again.
5. Pull forward off the scale and park in a trailer space. Drop the trailer there. Never unhitch on the scale.
6. Drive the truck back on alone and weigh it again, with the same people, cargo, fuel and hitch hardware aboard.
7. Subtract the truck-alone weight from the truck's coupled weight to get tongue weight; with a weight-distribution hitch, use the bars-released reading, never the tensioned one. The combined gross minus the truck alone is the trailer's full loaded weight.

Throughout this guide one illustrative rig carries every number: a half-ton crew-cab truck towing a travel trailer with a weight-distribution hitch, all figures in pounds. It is a composite example, not a real vehicle, and the figures are here so each step reconciles against the next. Your own labels will read differently, so always weigh against yours. The truck's ratings are GVWR 7,000, front GAWR 3,650, rear GAWR 3,950, payload 1,600 (GVWR 7,000 minus a curb weight near 5,400), a max tow rating of 9,000 under SAE J2807, and a GCWR of 14,500. The trailer's GVWR is 7,700.

Which axle goes on which platform?

Platform 1 reads your steer axle, platform 2 reads your drive axle, and platform 3 reads your trailer axle: three groups, three plates, one drive-through. CAT puts it plainly: position the steer axle on platform 1, the drive axle on platform 2, and the trailer will normally show up on platform 3. A truck and travel trailer line up to that mapping without any fuss, because the truck's two axles take the first two plates and the trailer's axle group lands on the third.

Two positioning rules keep the reading accurate. No tire may straddle the gap between two platforms, or the weight lands on the wrong group. And a long spread-axle or multi-axle trailer that will not fit on a single platform needs a second pull-forward pass so each axle group gets read cleanly. The scale itself reports axle-group weights and a total gross. It cannot weigh each corner of the rig, which is exactly why tongue weight has to be derived rather than read off a line.

The passes: the rig as you tow it, bars released, then the truck alone

Weigh the coupled rig as you tow it, then (with a weight-distribution hitch) coupled again with the spring bars released, and finally the truck by itself after unhitching in a parking space. You never drop the trailer on the scale deck. On the worked rig the coupled pass, bars tensioned, reads steer 3,210, drive 3,710 and trailer axle 5,980, for a combined gross of 12,900 lb. Those are the travel weights you check against your ratings.

For the bars-released reading, arrange the measurement with the scale operator and follow your truck and hitch instructions; never drive with required weight distribution disabled to get it. With the bars released, the worked truck reads 7,000 lb across steer and drive, and the trailer axle 5,900 lb: the same 12,900 lb gross, rearranged. The steer axle reads lighter and the drive axle heavier on this pass, because nothing is levering the tongue's load forward any more, so use it for the tongue, not as your travel weights.

For the last pass, pull off, park, and unhitch the trailer in a trailer space, then drive the truck back onto platforms 1 and 2 alone. Trip-loaded but unhitched, the worked truck reads steer 3,200 and drive 2,900: a truck gross alone of 6,100 lb. Disconnecting a trailer on the scale platform is prohibited, holds up the line behind you, and is unsafe, so the drop always happens off the deck. With the weighs done you hold three truck figures: 6,920 lb on its axles as you tow (3,210 + 3,710), 7,000 lb with the bars released, and 6,100 lb on its own. The gap between the last two is the tongue.

How do you get tongue weight from your CAT scale numbers?

Tongue weight is the truck's coupled weight with the spring bars released minus its solo weight (on the worked rig, 7,000 − 6,100 = 900 lb), because the part of the trailer that is not sitting on its own axles is pressing down on the truck through the hitch. The scale never reads the tongue directly; you back it out by subtraction. Without a weight-distribution hitch, your ordinary coupled weigh is already a bars-free reading, so you use that. The trailer's full loaded weight, its gross trailer weight, is the combined gross minus the truck alone: 12,900 − 6,100 = 6,800 lb, which matches the bars-released trailer axle plus the tongue (5,900 + 900). And the tongue as a share of that gross is 900 ÷ 6,800 = 13.24%, which sits inside the 10–15% band a travel trailer wants.

The 10–15% target is the figure trailer makers, hitch manufacturers and RV authorities all converge on: CURT, Weigh Safe, eTrailer and the RV Geeks each state the loaded tongue should be roughly 10–15% of the gross trailer weight, with too little inviting sway and too much squatting the rear and lightening the steering. The bars come off for that weigh because, tensioned, they lever part of the tongue's load forward onto the steer axle and back onto the trailer's own axles, as Equal-i-zer's weight-distribution explanation describes. Run the same subtraction on the bars-tensioned weigh and the worked rig gives 6,920 − 6,100 = 820 lb, 80 lb short on this illustrative rig, because that much of the tongue's load is riding on the trailer's axles. On your rig the shortfall depends on how hard the bars are set, and can be larger. How the hitch moves that load (and how to read the steer axle to confirm it is doing its job) is its own subject, handed off to the US weight-distribution-hitch guide.

Does comparing the steer axle solo and coupled tell you anything?

The solo and bars-engaged steer readings show how the axle load changed. You also need the bars-released reading to check the hitch setting. The worked rig reads 3,200 lb on the steer axle solo and 3,210 lb with the bars engaged. That is 10 lb above the solo reading, so do not treat it as a recommended setting. Use all three readings to calculate front-axle-load restoration, then compare the result with the tow-vehicle and hitch instructions. Being below the 3,650 lb front GAWR does not confirm correct weight distribution. The dedicated US weight-distribution hitch and front-axle-load guide explains that check.

What does it cost, and how do you pay?

A CAT scale weigh runs around $15 for the first ticket, with a qualifying reweigh near $5. But prices change, so check catscale.com for current pricing rather than treating any figure as fixed. You pay one of two ways. In person, you push the intercom button on the scale, the cashier records your details, you pull off, and you collect the printed ticket inside. Or you use the Weigh My Truck app: it confirms the scale location and your truck details, the guaranteed weight appears on the screen once the weighmaster has it, and a PDF is emailed to you, a service CAT offers at no additional charge from CAT Scale itself.

A reweigh qualifies for the lower price only under set conditions: the same vehicle, the original full-price ticket presented and recorded, the same scale, and within 24 hours. That matters for the extra passes: ask the operator how your truck-alone and bars-released weighs will be charged, because the policy names the same vehicle, trailer included. The scale handles your whole rig comfortably: CAT scales are certified in the state they sit in and weigh vehicles from 2,000 to 200,000 lb, so the worked rig's 6,100 to 12,900 lb sits well inside the range.

Why pay for a weigh instead of trusting the spec sheet?

A spec sheet gives you a manufacturer's estimate; a CAT scale gives you a guaranteed, court-defensible weight of your rig as it actually sits loaded. Overloaded RVs are a documented safety problem, not a hypothetical. CAT guarantees both the axle weights and the gross weight: if the scale is wrong and you get a fine, CAT reimburses it, and if the scale is right, a representative appears in court. That guarantee is why a CAT weight settles an argument a brochure number cannot.

The reason to bother is on the federal record. In its 2007 final rule adding cargo-carrying-capacity labels to recreation vehicles (72 FR 68442, effective June 2 2008), NHTSA cited data from the RV Industry Association and the Recreation Vehicle Safety Education Foundation showing the scope of the overloading problem. A large share of the rigs that get weighed come in over one rating or another, which is exactly why producing real numbers, rather than assuming the brochure figures, is worth the $15. To turn the measured pounds into a pass or a fix you read them against your ratings, and the towing weight ratings guide explains what each rating means and which one tends to bind first.

Reading your CAT numbers against your ratings

Once you have the measured weights, check each one against the matching rating on your labels. On the worked rig every combination, trailer and axle check clears, but the truck itself is the one that runs out of room. Your truck's GVWR and per-axle GAWR are on the Safety Compliance Certification Label in the driver's-side door jamb, your vehicle-specific payload is on the Tire and Loading Information label on the B-pillar, and the trailer carries its own GVWR on its own label. Line the measured pounds up against them:

Here is the finding this rig produces. The combination has 1,600 lb of headroom, the trailer 900 lb, and each axle clears its GAWR with room to spare (240 lb on the drive axle, 440 lb on the steer), yet the truck sits at 6,920 lb against a 7,000 lb GVWR, with just 80 lb left. The payload is spent: curb weight near 5,400, plus roughly 700 lb of occupants and gear, plus the 900 lb tongue, comes to 7,000 lb, the whole 1,600 lb payload. The scale shows 80 lb to spare only because the tensioned bars hand that much of the tongue's load to the trailer's axles. So the limit that bites first on this rig is the truck's own loaded weight, not the trailer rating or the tow number. Where that payload goes, and how to claw room back, is the job of the payload vs towing capacity guide; decoding the printed ticket line by line belongs to how to read a CAT scale ticket; and tuning the hitch belongs to the weight-distribution hitch and front-axle-load guide.

How loadmate turns your CAT weights into a verified check

You have just produced real pounds (a truck near its GVWR, a 900 lb tongue, a 6,800 lb trailer), and a printout on the dashboard recalculates none of it the next time you load. The live question is whether your own rig clears its limits on those measured numbers rather than on a spec-sheet guess, and that is the gap between reading the scale and acting on it. Enter the figures from your weigh into loadmate and the check runs on what the rig actually showed: the measured per-axle and gross values, kept with the source context of where the reading came from, with the confidence badge moving from Estimated to Verified as the baseline shifts off a typed-in estimate.

The ticket is the start of a useful baseline. In loadmate, recorded weigh-ins and the loads you add afterwards stay connected, so extra water, a generator or a different packing arrangement can be reviewed against the rig's limits. Explore loadmate in the app to see how a measured day stays useful between scale visits.

loadmate gets you ready for the truck scale, it does not stand in for it. For legal weight evidence, use a certified truck scale. See /safety-disclaimer.

Related guides

The rest of the Wave-1 guides are live; the US vehicle hub is publishing as the US set rolls out. This guide links up to the pillar and across to each sibling:

• Towing weight ratings explained: GVWR, GCWR, GAWR and payload, and which rating binds first (the pillar; start here)
• How to read a CAT scale ticket: turning the printed CAT scale numbers into a pass or a fix, the read half of this pair
• Weight-distribution hitch and front-axle load: reading and restoring the front-axle weight a heavy tongue takes off
• Tongue weight vs payload: how the trailer's tongue weight spends your truck's payload
• Payload vs towing capacity: why the two are different numbers and which one limits your trip
• Trucks whose margins turn on a measured weight: Ford Ranger, Toyota Tacoma, Jeep Wrangler