The four numbers that decide what you can tow
| Term | What it means |
|---|---|
| GVM | Gross Vehicle Mass — the maximum the loaded truck itself may weigh |
| GCM | Gross Combination Mass — the maximum for truck and trailer together |
| Braked towing capacity | The maximum trailer mass, assuming nothing else is exceeded |
| Tow ball download | Weight the trailer puts on the ball — it counts against your GVM |
The most common mistake we see: a truck rated to tow 4,500 kg that runs out of GCM long before the trailer reaches 4,500 kg once the family, fuel, canopy and ball weight are on board.
Signs your towing setup isn't right
- The rear squats noticeably and the front feels light with the van hitched
- The truck sways or feels unstable behind trucks and buses on the highway
- Brakes feel spongy or the truck takes longer to pull up while towing
- You've never actually had the combination weighed on a weighbridge
- The trailer brake controller light flickers or the trailer brakes feel weak or grabby
Towing figures by brand — what to check, not assume
RAM 2500/3500
Australian-converted RAM 2500/3500 models carry strong braked towing ratings, commonly in the 4,500 kg region, but GCM is frequently the real limit once the truck, passengers, canopy and ball weight are all counted — not the trailer's own rating.
Silverado & GMC Sierra/Denali
Local RHD conversions of Silverado 1500 and HD models, and GMC Sierra/Denali, carry factory-backed US towing figures adjusted for the Australian compliance plate — always check the compliance plate rating, not the US marketing figure, since they can differ.
Ford F-150 & F-250/F-350
RHD-converted F-Series trucks have strong towing figures on paper, but as with all these conversions, added weight from the conversion itself can eat into payload and GVM headroom, so a weighbridge check before a big trip is worthwhile.
Towing setup work we do
- Weight and compliance assessment against GVM, GCM and axle ratings
- Electric brake controller supply, fitment and calibration
- Tow bar, hitch and wiring inspection and repair
- Weight distribution hitch setup and advice
- Rear load support — airbags or heavier springs
- Pre-trip caravan and towing inspection before you leave
What a weight and towing assessment involves
- 1Confirm your truck's compliance plate figures for GVM, GCM, front and rear axle ratings and braked towing capacity.
- 2Weigh the truck as you'd actually drive it — full fuel, passengers, canopy, tools.
- 3Weigh or estimate the trailer/caravan ball weight and total mass.
- 4Add it all up against GCM, not just the towing capacity figure in isolation.
- 5Recommend load support, a weight distribution hitch or, if genuinely needed, a GVM/GCM upgrade.
Cost and how long it takes
A basic weight and compliance assessment can often be done in under an hour if you can bring the truck and trailer together, or supply recent weighbridge tickets. Brake controller fitting, tow bar work and hitch setup are quoted on enquiry depending on the parts and vehicle involved.
Before a big trip
A towing inspection covers brakes and brake fluid condition, driveline and diff oils, cooling system, tyres and pressures, suspension, wheel bearings, battery and charging, and the trailer connection itself. Towing a heavy van up the range in a Queensland summer is the hardest work your truck will ever do — it's worth knowing everything is right before you leave the Sunshine Coast, not after.
Frequently asked questions
- How much can a RAM 2500 tow in Australia?
- Australian-converted RAM 2500 models are commonly rated around 4,500 kg braked, but your usable limit depends on GCM and how heavily the truck itself is loaded. We can weigh your combination and give you real figures.
- Does tow ball weight count towards GVM?
- Yes. Tow ball download is carried by the truck, so it counts against your GVM and rear axle rating — commonly 10% of trailer mass, so 350 kg on a 3.5 tonne van.
- How do I know my truck's actual towing limit?
- Check your compliance plate for GVM, GCM and braked towing capacity, then weigh the truck loaded as you'd actually drive it. Whichever figure you hit first — not the biggest number on the brochure — is your real limit.
- Is it legal to tow over my GCM even if I'm under the trailer's rated capacity?
- No. Exceeding GCM is illegal even if the trailer itself is within its own rating, and it can invalidate insurance in a claim. GCM covers the combined weight of the truck and trailer together.
- Do I need a weight distribution hitch for a caravan?
- Often yes, for heavier vans, to spread tow ball weight back across all axles and improve steering and braking control. We can assess your combination and recommend whether one suits your setup.
- How much does a towing inspection cost before a big trip?
- It depends on what's checked and whether any parts need replacing, so it's quoted on enquiry — but a pre-trip inspection is inexpensive compared with a breakdown or brake failure towing a caravan interstate.
- Can you fit a brake controller to my RAM or Silverado?
- Yes, we supply and fit electric brake controllers, including integrated factory-style units where available, and calibrate them correctly to your trailer's brakes.