Head to head
Ifor Williams HB511 vs Stewart GX 15 FT
The Stewart GX 15 FT is rated 12.3 tonnes heavier gross.
Last reviewed 13 September 2026
Key differences
- Gross weight: the Stewart GX 15 FT is rated 12.3 tonnes heavier gross.
Specifications side by side
| Ifor Williams HB511 | Stewart GX 15 FT | |
|---|---|---|
| Gross weight | 2,700kg | 15,000kg |
| Unladen weight | 1,000kg | - |
| Internal length | 3.52m | - |
| Internal width | 1.79m | - |
| Brakes | Braked | - |
| Length | - | 7,900-9,700mm (26-32ft) |
| Tare weight | - | 3,980kg |
| Axles | - | 125mm dia., 10-stud, 420x180mm brakes |
| Tyres | - | 385/65Rx22.5 standard, 435/50Rx19.5 flotation option |
Sources: Ifor Williams HB511, Stewart GX 15 FT. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the HB511 if...
The wider step up from the HB506, for larger horses or owners who want more room in transit. The extra 12cm of internal width and 36cm of length cost 80kg unladen, which is worth checking against your tow vehicle before choosing it over the HB506.
Listed by
- Trek-Trailers Suffolk - Bury Saint Edmunds
- R M Trailer Centre - Middlesbrough, North Ormesby
- Blains Trailers & Tyres - Hemel Hempstead, Great Gaddesden
- Horse Trailer Sales - Robertsbridge, Staplecross
- Trek-Trailers Three Counties - Hereford
- Barnwell Trailers Ltd - Peterborough, Oundle, Barnwell
Buy or hire the GX 15 FT if...
- you want one that is rated 12.3 tonnes heavier gross
A 15-tonne flat trailer from Scottish maker Stewart Trailers, built for farms and hire fleets moving bulky loads such as bales or machinery. The choice of standard or flotation tyres lets it be set up for road use or softer ground.
Listed by
- Rising Sun Trailer Hire - York
Common questions
What is the difference between the Ifor Williams HB511 and the Stewart GX 15 FT?
The Stewart GX 15 FT is rated 12.3 tonnes heavier gross. The Ifor Williams HB511 is a two-horse trailer, twin axle, wider body; the Stewart GX 15 FT is a twin-axle flat trailer for agricultural and general haulage use.
Can I tow the Ifor Williams HB511 or the Stewart GX 15 FT on a car licence?
Stewart GX 15 FT is rated over 3,500kg gross, which is beyond what a car can tow in the UK.
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