Head to head
Ifor Williams HB511 vs Stewart GX 18-23 S
The Stewart GX 18-23 S is rated 17.3 tonnes heavier gross.
Last reviewed 13 September 2026
Key differences
- Gross weight: the Stewart GX 18-23 S is rated 17.3 tonnes heavier gross.
Specifications side by side
| Ifor Williams HB511 | Stewart GX 18-23 S | |
|---|---|---|
| Gross weight | 2,700kg | 20,000kg |
| Unladen weight | 1,000kg | - |
| Internal length | 3.52m | - |
| Internal width | 1.79m | - |
| Brakes | Braked | - |
| Body size | - | 6,700 x 2,450 x 1,500mm |
| Cubic capacity | - | 23m3 grain, 39m3 silage |
| Tare weight | - | 5,900kg |
| Axles | - | 125mm dia., 10-stud, 420x180mm brakes |
Sources: Ifor Williams HB511, Stewart GX 18-23 S. 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 18-23 S if...
- you want one that is rated 17.3 tonnes heavier gross
An 18-23 tonne tipping trailer built for grain and silage haulage, with an easy-sheet system so one person can cover a loaded trailer without climbing on top. Its monocoque steel body gives it the extra capacity over Stewart's standard flat trailers.
Listed by
- Rising Sun Trailer Hire - York
Common questions
What is the difference between the Ifor Williams HB511 and the Stewart GX 18-23 S?
The Stewart GX 18-23 S is rated 17.3 tonnes heavier gross. The Ifor Williams HB511 is a two-horse trailer, twin axle, wider body; the Stewart GX 18-23 S is a twin-axle tipping grain and silage trailer with an easy-sheet cover system.
Can I tow the Ifor Williams HB511 or the Stewart GX 18-23 S on a car licence?
Stewart GX 18-23 S is rated over 3,500kg gross, which is beyond what a car can tow in the UK.
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