To calculate your Tank 300 roof load, add the rack, mounting hardware, attached accessories and everything packed above the roof. Then check that configuration against the vehicle and equipment documentation for the conditions you will drive in. A rack's advertised capacity is not automatically your remaining cargo allowance.
A roof platform can look almost empty while already carrying substantial weight. The platform itself, its feet, an awning and a storage box all count before you add camping gear. A useful plan starts with a set of scales and a list, not the size of the empty space on top.
This worksheet helps you build that list and identify missing information. It does not prescribe one roof-load number for every Tank 300. If you are still choosing between bars, platforms and roof storage, start with our Tank 300 roof rack and load guide, then use the calculation below for your shortlist.
Editorial note: the cover and explanatory graphics are AI-generated concepts. The MK Spark component photograph is from our store listing. Illustrations do not establish product fitment or load capacity.
Start with the rating, not a number from another build
Record your model year, powertrain, trim and roof arrangement. Include any replacement rails or mounting system already fitted. Ask GWM or your dealer for the current roof-loading guidance for that exact vehicle, and obtain the selected rack manufacturer's fitting instructions.
Keep three questions beside every stated limit:
- What is being rated? The vehicle roof, complete rack system, one crossbar, an accessory bracket or a cargo container?
- What weight is included? Does the number include the rack and mounts, or only cargo placed on an already-installed system?
- Under what conditions? Sealed-road travel, unsealed/off-road travel, or stationary use?
Do not compare numbers until their meaning is clear. Two ratings can both be correct while describing different loads. A missing or unclear rating is a question to resolve, not spare capacity you can assume.
GWM's Australian Tank 300 accessories page lists different crossbar, tray and rail combinations and asks owners to confirm compatibility with a dealer. An accessory name alone does not establish which complete system belongs on your vehicle.
Make a roof-load inventory you can actually weigh
Use the table below as a packing worksheet. Write the mass in kilograms and note whether you weighed the item or used a supplier figure. For a heavy or awkward rack, have an installer confirm its assembled weight rather than attempting an unsafe lift.
| Item to record | What to include | Your mass and evidence |
|---|---|---|
| Rack or crossbars | Platform or bars in the exact chosen configuration | ___ kg; weighed / supplier |
| Mounting system | Feet, brackets, adapters and hardware not already included above | ___ kg; weighed / supplier |
| Fixed accessories | Awning, awning brackets, light mounts or other roof-supported equipment | ___ kg; weighed / supplier |
| Empty storage | Roof box or bag, including its mounting kit | ___ kg; weighed / supplier |
| Packed contents | Every item inside the box or bag | ___ kg; weighed |
| Restraint equipment | Straps and holders not counted in another row | ___ kg; weighed |
| Travel extras | Any ladder, bedding or other equipment carried on the roof while driving | ___ kg; weighed |
Give each item one row only. If an assembled rack weight already includes its feet, mark those feet as included instead of adding them again. Conversely, a bare-platform figure should not silently stand in for the complete installation.
Weigh the trip-ready configuration. A box's capacity in litres describes volume, not the weight of what you put inside it. A bag weighed empty last month tells you little about the bag after blankets, chairs and tools have been packed for this trip.
Calculate the total, then test each applicable limit
The basic arithmetic is:
Total roof-supported travel weight = rack + mounts + attached accessories + containers + packed contents + restraint equipment.
Use the inventory to avoid omissions and double-counting. Then compare the correct subtotal with each limit in the relevant documents. For example, a vehicle limit may cover the complete roof load, while a particular holder has a separate limit for the item it carries. Both checks must pass.
AI-generated calculation graphic. These are teaching figures, not a Tank 300 roof rating or the specifications of a rack sold in our store.
Worked example: 24 + 6 + 18 = 48 kg
Imagine a planning list with a 24 kg rack, 6 kg of mounting hardware and accessories, and 18 kg of packed cargo. The total is 48 kg. That result describes the proposed load; it does not tell you whether the installation is permitted.
You still need the exact vehicle and system limits. If the documentation provides a total roof allowance that includes the rack, subtract the complete non-cargo installation weight to find the vehicle-side space left for cargo. Check the rack, mounts and accessory limits separately using their stated definitions. The smallest remaining allowance governs the proposed cargo, provided the combination is approved in the first place.
If the documents do not explain what is included, send the weight list to the manufacturer or installer and request a written interpretation. Do not subtract the rack twice from a figure that is already a cargo-only allowance.
Keep an allowance for real packing changes
Do not use an approximate supplier mass as permission to load right up to a limit. Record what remains uncertain and weigh the finished setup before travel. A different mounting kit, extra bag or later-added awning changes the calculation.
Our practical recommendation is to save two versions of the list: the normal weekend configuration and the heavier trip configuration. Date each one. Recalculate when equipment changes instead of relying on a photo of a previous trip.
Why the rack's own weight matters: a store example
The MK Spark Roof Rack for GWM Tank 300 is currently listed with an approximate weight of 38.92 kg and supplier-described manganese-steel construction. Its fitment table lists Petrol / Hybrid, but does not specify exact model years. Those details require confirmation before ordering.
Existing store product photograph. Confirm the current supplied kit and assembled mass; the photograph is not a load test or an installation instruction.
The useful lesson is not that heavier or lighter automatically means better. It is that the rack's mass belongs in the budget. The listed MK Spark weight is roughly 14.9 kg more than the hypothetical 24 kg rack in the example. That difference cannot be ignored when comparing otherwise equivalent packing plans.
The listing we checked does not establish a verified dynamic, off-road or stationary rating. We therefore do not turn its material description or approximate weight into a carrying-capacity claim. Ask about the complete mounted system, exact vehicle version and intended use before treating it as a suitable choice.
Driving, off-road and parked loads need separate checks
Rhino-Rack's load-rating explanation distinguishes sealed-road, off-road and stationary conditions. It also notes that attached accessories count towards the load. Use the instructions for your own system; an off-road reduction from an unrelated rack is not a universal formula.
In practice, keep separate entries on your worksheet for the conditions your itinerary includes. If a route changes from sealed roads to rough tracks, confirm that the packed configuration still meets the applicable requirements before continuing.
A rooftop tent adds a second use case
For travel, record the closed tent, its mounts and any bedding or ladder carried with it. For camping, confirm the deployed tent arrangement and permitted occupant load under the vehicle, rack and tent instructions. A stationary number does not authorise the same weight while driving.
AI-generated illustration of two different operating conditions. The generic vehicle and tent do not demonstrate Tank 300 compatibility.
Rhino-Rack's rooftop-tent guidance likewise treats vehicle suitability, rack type and tent mounting as separate checks. A tent that physically sits on a platform still needs documented compatibility. Do not invent a static multiplier from a driving rating or assume an extra crossbar approves a tent installation.
Check height, restraint and the whole vehicle too
A correct weight total is only one part of the plan. Before travel, measure the vehicle's actual loaded height and check the operation of the sunroof and clearance around the antenna. Inspect the installed system according to its instructions, including the specified fasteners, sealing and inspection intervals.
The National Transport Commission's light-vehicle load restraint guidance explains that loads must be restrained, stay within mass limits and avoid dangerous projections or obscuring lights and number plates. Consult the linked state or territory guidance where needed. This worksheet is not a compliance certificate.
Also confirm whole-vehicle mass and axle limits. Moving a heavy item from the roof into the boot does not remove its weight from the vehicle. It requires suitable interior restraint and a fresh packing assessment. Our Tank 300 trunk storage checklist can help you consider the cargo-area alternative.
Send a useful fitment enquiry
For a specific answer, send this information through our roof-rack fitment enquiry page:
- Vehicle model year, powertrain and trim.
- Photos of the existing rails or mounts and any roof accessories.
- The rack and accessory product links or exact variants you are considering.
- The completed weight inventory, identifying estimates and items already included in kit weights.
- Intended road conditions and whether a rooftop tent is part of the plan.
- Relevant vehicle and equipment load-rating wording, including what each figure covers.
That makes it easier to identify an unsuitable combination before you order. Do not post a VIN or personal vehicle documents in public blog comments; use a private support conversation if identification is needed.
Tank 300 roof-load calculation FAQs
Is the rack weight part of the roof load?
Yes. Include the weight supported by the roof, including the rack and its mounting system. When comparing it with a published limit, check whether that limit already accounts for any components.
Can I use one roof-load number for every Tank 300?
Not from this worksheet. Confirm your exact vehicle and installed roof system with the current documents. A number copied from a different model, market or accessory package may describe a different configuration.
Does a bigger platform let me carry more weight?
A larger footprint gives more mounting space, not automatic permission for more mass. It may also add empty weight. Check the complete system and vehicle limits before adding cargo.
What if I cannot find the static or off-road rating?
Request it from the relevant vehicle or equipment supplier. Leave that use case unapproved until you have a clear answer; do not infer it from the on-road figure.
What should I do before buying a roof tent?
Complete the travel-weight inventory first, then confirm tent-to-rack compatibility and parked-use requirements. If either check is unresolved, pause the purchase and ask for the missing documentation.
The takeaway: weigh the complete setup, understand what each rating covers and keep the calculation with your packing list. Choose a roof system around the load you can document, not the amount of gear you can squeeze onto it.
