Choosing the Right GVM for Your GT Digger Trailer
The single biggest mistake we see when people are picking a digger trailer is choosing based on deck size alone and only checking the GVM afterwards. Get the GVM wrong and you're either overpaying for capacity you'll never use, or legally and physically unable to carry the machine you actually own.
What GVM actually means
GVM (Gross Vehicle Mass) is the maximum legal weight of the trailer plus everything loaded on it. It is not the same as payload. Payload is what's left over once you subtract the trailer's own weight (its tare weight) from the GVM — and payload is the number that actually matters when you're working out whether your digger will fit.
Payload = GVM − Tare Weight
A trailer with a higher GVM doesn't always mean a big jump in usable payload, because heavier-duty trailers are often built with a heavier chassis to handle the extra rating. Always check the payload figure specifically, not just the GVM on the spec sheet.
GT Digger Trailer payloads at a glance
| Model | Deck Size | GVM | Payload | Braking |
|---|---|---|---|---|
| CTDIG25 | 2.95m x 1.45m | 2500kg | 1970kg | Hydraulic |
| CTDIG25L | 3.60m x 1.80m | 2500kg | 1870kg | Hydraulic |
| CTDIG30 | 2.95m x 1.45m | 3000kg | 2390kg | Mechanical |
| CTDIG30L | 3.60m x 1.80m | 3000kg | 2290kg | Mechanical |
| CTDIG35 | 2.95m x 1.45m | 3500kg | 2850kg | Mechanical |
| CTDIG35M | 2.95m x 1.80m | 3500kg | 2800kg | Mechanical |
| CTDIG35L | 3.60m x 1.80m | 3500kg | 2700kg | Mechanical |
How to match GVM to your machine
Work out your digger or excavator's real operating weight before you shop — not the base spec-sheet weight. Check the machine's own data plate, and remember to account for:
- Any attachments left fitted (buckets, rippers, augers)
- A full fuel tank
- Any onboard tools, spare parts or gear you tend to leave in the cab
Then leave a reasonable safety margin — don't buy a trailer with a payload that exactly matches your machine's weight on paper. Wear, added attachments, and small errors in stated machine weight all eat into that margin fast.
Single vs wide deck
The 'L' and 'M' suffixes in the GT range (CTDIG25L, CTDIG35L, CTDIG35M) indicate a longer or wider deck rather than a heavier rating — useful if your machine is physically large but not necessarily heavier. Check both the deck dimensions and the payload figure against your machine.
Braked vs unbraked
All GT Digger Trailers in this range sit well above 2500kg GVM, which under NZTA rules means a service brake and a parking brake are both required, acting on at least one axle. GT's digger range is fitted with hydraulic override braking on the smaller CTDIG25/25L models and mechanical override braking on the 30 and 35 series — see each product page for the specifics, and talk to us if you're not sure what your combination needs.
Still not sure which GVM is right for your machine? Get in touch and we'll help you match a trailer to your equipment, or browse the full GT Digger Trailer range.
