Before you buy a trailer: questions to ask first

Last updated: 2 November 2026, The Trailer Shop, Glenfield

The Trailer Shop in Glenfield has built custom and boat trailers in Auckland since 1991. Before you buy a trailer, work out what you’ll carry and what it weighs (GVM), whether you need single or tandem axles and brakes, how it will handle salt water, and who will service it and supply parts after the sale. This guide covers each question.

What size trailer and GVM do I need?

Start with the heaviest load you’ll realistically carry, then add the trailer’s own weight. That total is the gross vehicle mass (GVM), and it has to stay within the trailer’s rating and your vehicle’s towing limit. We focus on trailers under 3,500 kg GVM, which covers most domestic, trade and boat use.

• Measure your longest and widest load, not just the average one.
• Check your vehicle’s towing capacity in the owner’s manual or on the towbar plate.
• Leave headroom. A trailer that’s always at its limit wears faster.

Browse sizes on all trailers or box trailers.

Single axle or tandem axle?

A single axle trailer is lighter, cheaper to run and easier to move by hand. It suits most garden, tip and light trade loads. A tandem trailer spreads heavier loads across two axles, tows more steadily at motorway speed, and is safer if a tyre blows. Pick by load weight and how far you’ll tow.

Heavier boats, car trailers and big trade loads usually go tandem. If you’re in between, tell us what you carry and we’ll give you a straight answer.

Does my trailer need brakes in NZ?

Whether a trailer needs brakes, and which type, depends on its laden weight and your towing vehicle. NZTA (Waka Kotahi) sets the rules, so check the current requirements on the NZTA website before you choose. Ask the builder which rule your trailer is built to.

We don’t publish weight thresholds here because NZTA updates its rules. Light-vehicle rules changed on 1 November 2026. Tell us your load and vehicle and we’ll build to the right braking setup.

Will the boat trailer actually fit my boat?

A boat trailer should be set up for your hull, not just your boat’s length. Roller or skid positions, bow stop height and axle position all affect how easily you launch and retrieve, and how the weight sits on your towball. Bring your boat’s make, model and length, or the boat itself.

We’re the NZ agent for Dunbier boat trailers and we also build custom boat trailers in Glenfield. See boat trailers or custom builds.

Rollers or skids?

Rollers make launching and retrieving easier at shallow ramps and suit heavier fibreglass hulls. Skids (bunks) support the hull along its length and suit many aluminium boats. They’re also simpler to maintain. The right choice depends on your hull, where you launch and how you retrieve.

What about salt water and galvanising?

If a trailer goes in the sea, corrosion protection matters more than almost anything else. Hot-dip galvanising protects steel inside and out far better than paint. After every launch, rinse the trailer, especially the brakes, bearings and springs, with fresh water. Regular servicing catches problems early.

Ask us which of our builds are hot-dip galvanised as standard. Corrosion protection products are in our CorrosionX range.

What warranty should I expect?

Ask what’s actually covered, for how long, and what you have to do to keep it. New trailers we manufacture carry a 10-year limited structural warranty on the main frame. It applies to the original purchaser, the trailer has to be registered within 30 days, and it needs servicing at least every 12 months. Commercial, hire or daily industrial use is covered for 12 months.

Fittings, decks, guards and accessories aren’t structural. They carry component warranties passed on from our suppliers (up to 5 years, depending on the part). Conditions apply.

Who services it and supplies parts after I buy?

This is the question people forget. Find out who will service the trailer, fix it, and stock bearings, lights and couplings for it years from now. A lot of places sell trailers but won’t look after them afterwards. We service and repair trailers in our Glenfield workshop and stock 1,100+ trailer parts online.

• Service every 12 months, or every 6 months for heavy use.
• We normally pick up and drop off trailers Auckland-wide on request.
• Book your trailer WoF with us and we’ll get it sorted.

See repairs and services.

Can I get finance?

Yes. Finance is available through MTF, subject to lending criteria. Talk to us about the trailer you want first, then we can point you to the MTF application.

Questions to ask before you buy a boat trailer (checklist)

1. Is it galvanised, and how?
2. Is it set up for my hull, not just my boat’s length?
3. Rollers or skids for my boat and my ramp?
4. Who services it after I buy, and are the parts easy to get?
5. What does the warranty cover, for how long, and what are the conditions?

Frequently asked questions

How do I know what size trailer to buy? Add up the heaviest load you’ll carry plus the trailer’s own weight. Keep that total within the trailer’s GVM and your vehicle’s towing limit. Measure your longest and widest load too.

Is a tandem trailer better than a single axle? A tandem suits heavier loads and longer tows because it’s more stable and spreads the weight. A single axle trailer is lighter, cheaper to run and fine for most light loads.

Does my trailer need brakes? It depends on the trailer’s laden weight and your towing vehicle. NZTA sets the rules, so check NZTA’s current towing guidance and ask the builder which rule the trailer is built to.

What should I ask before buying a boat trailer? Ask whether it’s galvanised, whether it’s set up for your hull, whether rollers or skids suit your boat, who services it afterwards, and what the warranty covers.

What warranty comes with a Trailer Shop trailer? New trailers we manufacture carry a 10-year limited structural warranty on the main frame for the original purchaser. Registration within 30 days and yearly servicing are required. Commercial, hire or daily industrial use is covered for 12 months. Conditions apply.

How often should a trailer be serviced? Every 12 months, or every 6 months for heavy-use trailers.

Can I get finance on a trailer? Finance is available through MTF, subject to lending criteria.

Who to call

The Trailer Shop, Glenfield Unit 5, 95 Ellice Road, Glenfield, Auckland 0629 Phone: 09 444 5571 · info@thetrailershop.co.nz Hours: Mon–Thu 8am–5pm, Fri 8am–4:30pm, Sat 9am–12pm. Closed public holidays and public holiday weekends.

Building trailers in Auckland since 1991. Get a quote · Browse trailers · Repairs and services