Calculators are only as good as the numbers you feed them. Brochure weights leave out options, gear and fluids, and guesses about tongue weight are often far off. Weighing your loaded rig once, the way you actually travel, answers every question at the same time. It takes about twenty minutes and costs little at most truck stops.
What you need
- A certified multi-platform scale. Truck stops and some farm, landscape or recycling yards have them. A three-platform scale reads the steer axle, drive axle and trailer axles separately.
- The rig loaded for a trip: fuel, people, water, propane, gear, the way you really travel.
- A place to unhitch nearby, ideally in the same parking lot, for the third pass.
- A pen, or a photo of each ticket.
Each pass usually means driving onto the scale, stopping with each axle group on its own platform, and using the intercom or app to request a weight. Ask staff if you are unsure; they help people with trailers every day. Weigh again after a few minutes for a reweigh, which is often cheaper than the first.
Pass 1: hitched, weight distribution engaged
Drive on with the trailer hitched and set up as you tow, bars tensioned if you use a weight distribution hitch. Position the steer axle on platform 1, the drive axle on platform 2 and the trailer axles on platform 3. Record all three.
Pass 2: hitched, weight distribution released
Pull around, release the spring bars (or chains) and drive over again in the same positions. If you don’t use weight distribution, skip this pass. Comparing passes 1 and 2 shows exactly how much load the bars move.
Pass 3: truck alone
Unhitch the trailer nearby, keep the same people and gear in the truck, and weigh the truck alone (steer and drive axles).
Turning tickets into answers
Write the readings as: S = steer axle, D = drive axle, T = trailer axles, with the pass number.
| What you want | Formula |
|---|---|
| Gross combined weight | S1 + D1 + T1 (compare with GCWR) |
| Truck alone (loaded, unhitched) | S3 + D3 |
| Loaded trailer | (S1 + D1 + T1) − (S3 + D3) (compare with trailer GVWR and tow rating) |
| Tongue weight | (S2 + D2) − (S3 + D3) |
| Tongue weight % | Tongue weight ÷ loaded trailer × 100 (aim for 10–15%) |
| Truck loaded for towing | S1 + D1 (compare with GVWR) — S1 and D1 against front and rear GAWR |
| Front axle restoration | (S1 − S2) ÷ (S3 − S2) × 100 |
A worked example
A pickup and travel trailer give these readings (lb):
| Pass | Steer | Drive | Trailer |
|---|---|---|---|
| 1: WD engaged | 3,560 | 3,820 | 6,240 |
| 2: WD released | 3,400 | 4,060 | 6,160 |
| 3: truck alone | 3,640 | 2,960 | — |
- Gross combined: 3,560 + 3,820 + 6,240 = 13,620 lb
- Truck alone: 3,640 + 2,960 = 6,600 lb; loaded trailer: 13,620 − 6,600 = 7,020 lb
- Tongue weight: (3,400 + 4,060) − 6,600 = 860 lb, which is 12.3% of the trailer: in range
- Front axle restoration: (3,560 − 3,400) ÷ (3,640 − 3,400) = 160 ÷ 240 = 67%
- Truck while towing: 3,560 + 3,820 = 7,380 lb against its GVWR, and 3,820 lb on the rear axle against its GAWR
The totals for passes 1 and 2 should match (13,620 lb in both here), because the bars only move weight around. Differences of 20–40 lb are normal scale tolerance; bigger ones mean something changed between passes.
Reading the results
- Tongue weight below 10%: move heavy items forward; see the trailer load balance calculator.
- Front axle restoration well under your manual’s target: add tension to the bars (often one more chain link or a different head tilt), then weigh again.
- Rear axle over GAWR: reduce cargo behind the rear axle and tongue weight, or increase weight distribution within the manual’s limits.
- Truck over GVWR: payload is exceeded; carry less in the truck or reduce tongue weight.
Plug your measured numbers into the weight distribution hitch calculator and theaxle load calculator to experiment with changes before your next weigh.
No scale nearby?
Tongue weight can be measured at home with a tongue weight scale, or with a bathroom scale and a beam using the lever method in thetongue weight scale calculator. Some public landfills, grain elevators and moving-truck lots also have scales that weigh the whole vehicle; drive on axle by axle to approximate per-axle readings.
When to weigh again
Weigh after buying a new trailer or truck, after adding heavy accessories (batteries, solar panels, a hitch, a bed cover, a toolbox), and whenever your packing changes significantly. Many RVers weigh once a season to make sure gear hasn’t crept up.
This guide is general information. Your vehicle, hitch, trailer and tire manufacturers’ ratings and instructions always come first, and towing rules vary by state, province and country. See our disclaimer.