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News
Lowest built hook lift trailer on the market – Metsjö MetaFlex sets the standard for low chassis height
The build height of a hook lift trailer determines everything: how tall a container you can legally transport, how safe the hooking process is and how stable the trailer is during transport. Metsjö designs and integrates the hook lift system directly into the chassis – making low build height a core competency that delivers measurable advantages on every run.
MetaFlex 40–60 reaches 891 mm build height in exchange position with 455/40R22.5 tyres – among the lowest available on the market for a tractor-drawn hook lift trailer system with full container capacity, and lower than most competitors who report 990–1250 mm on standard tyres.
What is build height on a hook lift trailer – and how is it measured correctly?
Build height is measured from the ground to the top of the roller on which the container's roll frame slides. This measurement – not the top of the chassis or any other reference point – determines how tall a container you can legally load.
It is important to compare hook lift trailers using the same measurement method. A supplier who measures to the top of the chassis reports a lower value than reality. Always ask for the measurement to the top of the roller.
Why low build height is critical – four concrete advantages
1. More legal container height – a direct commercial advantage
In Sweden and certain other EU countries, including Finland, the maximum vehicle height is 4.5 metres. In many other EU countries, 4.0 metres applies. Every millimetre of lower build height is one more millimetre of container you can use.
| Model | Build height (lowest spec) | Max container height within 4.0 m | Max container height within 4.5 m | Typical competitor level |
|---|---|---|---|---|
| MetaFlex 40–60 | 891 mm | 3009 mm | 3509 mm | 990–1250 mm |
| MetaFlex 50–65 | 937 mm | 2963 mm | 3463 mm | 1050–1300 mm |
| MetaFlex 60–75 | 1042 mm | 2858 mm | 3358 mm | 1250–1350 mm |
MetaFlex 50–65 reaches 937 mm in exchange position with 455/40R22.5 tyres – substantially lower than the 990–1250 mm commonly found on competing hook lift trailers in the same capacity class. Even MetaFlex 60–75 – the heaviest model in the range with a 100 mm taller main beam and approximately 30 tonnes of tipping and hooking force – remains at or below the level of competitors' lighter models, with a build height from 1042 mm with 455/40R22.5 tyres.
2. Stronger and safer hooking geometry
A lower build height produces a flatter exchange angle when the container is pulled on. This is not merely more comfortable – it is geometrically safer. Forces are distributed more evenly throughout the hooking sequence, stress on the chassis and hydraulics is reduced, and the risk of materials with a low angle of repose – grain, woodchip, excavated material – sliding off during container-on is markedly reduced.
| Advantage | MetaFlex 40–60 | MetaFlex 50–65 | MetaFlex 60–75 |
|---|---|---|---|
| More usable container height | ✔ | ✔ | ✔ |
| Lower centre of gravity | ✔ | ✔ | ✔ |
| Lower exchange angle | ✔ | ✔ | ✔ |
| Reduced risk of grain or woodchip sliding back during exchange | ✔ | ✔ | ✔ |
| More stable transport of tall containers | ✔ | ✔ | ✔ |
| Ability to maximise volume within legal height limits | ✔ | ✔ | ✔ |
3. Lower centre of gravity – better stability
A lower container sits lower on the trailer. This reduces the centre of gravity and improves stability in corners, on slopes and on uneven ground – particularly important with heavy loads in off-road conditions or on soft ground.
The relationship is mathematically well-defined. The rollover angle – the lateral tilt at which the vehicle begins to tip over – is calculated as:
Rollover angle = arctan(half track width ÷ system centre of gravity height)
Every 100 mm of additional chassis height raises the entire system's centre of gravity and reduces the rollover angle. With a typical 50 m³ biomass container, the difference in rollover angle between a low-built MetaFlex and a hook lift trailer with high build height can amount to several degrees. That may sound small, but on a slope or in a tight corner with a full load, it represents a tangible safety difference.
The relationship is also non-linear: the higher the chassis already is, the more stability is lost with each additional 100 mm. Low build height is not merely an advantage – it is a safety factor that compounds.
4. Hydraulic suspension with 350 mm travel
MetaFlex hydraulic suspension lowers the chassis fully onto the axles in exchange position for optimal geometry – and raises it to travelling position for good ground clearance. Total suspension travel is 350 mm. In travelling position, the chassis sits approximately 70–100 mm above exchange position.
How much container height is lost with higher build height?
The mathematics is straightforward but the consequences are significant. Every 100 mm of extra build height means 100 mm less usable container height within the same legal total height. For high-volume transport of grain, biomass and woodchip, this can equate to several cubic metres of lost load capacity on every single run.
| Build height in exchange position | Available container height within 4.0 m | Available container height within 4.5 m |
|---|---|---|
| 891 mm (MetaFlex 40–60) | 3009 mm | 3509 mm |
| 937 mm (MetaFlex 50–65) | 2963 mm | 3463 mm |
| 1042 mm (MetaFlex 60–75) | 2858 mm | 3358 mm |
| 1100 mm | 2800 mm | 3300 mm |
| 1200 mm | 2700 mm | 3200 mm |
| 1300 mm | 2600 mm | 3100 mm |
Build height in exchange position – three models, nine tyre sizes
| Tyre size | Dia (mm) | MF 40–60 | MF 50–65 | MF 60–75 |
|---|---|---|---|---|
| 455/40R22.5 | 930 | 891 mm | 937 mm | 1042 mm |
| 385/65R22.5 | 1085 | 968 mm | 1014 mm | 1120 mm |
| 710/35R22.5 IMP | 1088 | 970 mm | 1016 mm | 1121 mm |
| 560/45R22.5 IMP | 1096 | 974 mm | 1020 mm | 1125 mm |
| 600/50R22.5 IMP | 1196 | 1024 mm | 1070 mm | 1175 mm |
| 710/45R22.5 IMP | 1238 | 1045 mm | 1091 mm | 1196 mm |
| 800/40R22.5 IMP | 1238 | 1045 mm | 1091 mm | 1196 mm |
| VF 560/60R22.5 IMP | 1242 | 1047 mm | 1093 mm | 1198 mm |
| 650/50R22.5 IMP | 1248 | 1050 mm | 1096 mm | 1201 mm |
Values refer to exchange position (chassis fully lowered onto axles). In travelling position, build height is approximately 70–100 mm higher. Actual build height may vary depending on tyre manufacturer, inflation pressure, load and drawbar height – a high drawbar on the tractor tilts the trailer rearward and increases build height in practice. Contact Metsjö for exact measurements for your specific configuration.
Example: 50 m³ biomass container within 4.0 metre total height
MetaFlex 50–65 with 600/50R22.5 tyres has a build height of 1070 mm in exchange position. This allows for a container of 2930 mm – sufficient for a 50 m³ biomass container 2.55 metres wide with a total height under 4.0 metres. The same combination also fits comfortably within the 4.5 metre rule in Sweden and Finland. This is a concrete example of what low build height makes possible in daily transport of biomass, woodchip and grain.
Why are Metsjö's hook lift trailers built so low?
Hook lift system integrated into the chassis – Metsjö designs and integrates the hook lift system directly into the chassis, unlike solutions where a standalone hook lift unit is mounted on top of a standard chassis. This eliminates an entire structural level and is the single most important reason MetaFlex can achieve such low build height without compromising strength or capacity.
Telescopic cylinders with low installation height – Metsjö's compact tipping and hooking cylinders require minimal space within the chassis. This directly contributes to lower build height and is the same technology that enables MetaFlex to tip up to twice as fast as conventional systems.
Hydraulic suspension with lowering function – The chassis is fully lowered onto the axles in exchange position for the lowest possible build height when the container is being rolled on or off. The combination of low build height and lowerable suspension is unique in this class.
High-strength steel and optimised main beam – The main beam is designed as low as possible thanks to Metsjö's use of high-strength steel. Low profile without compromising structural integrity.
Free choice of tyre size – MetaFlex can be supplied with a wide range of tyre sizes. From 455/40R22.5 for the lowest possible build height to large flotation tyres for soft ground – tyre selection is one of the most powerful tools for optimising build height to suit your specific needs.
Frequently asked questions about low-built hook lift trailers
- What is build height on a hook lift trailer?
- Build height is measured from the ground to the top of the roller on which the container's roll frame rests. This is the measurement that determines how tall a container you can legally use.
- How low can a hook lift trailer be built?
- MetaFlex 40–60 reaches 891 mm in exchange position with 455/40R22.5 tyres – among the lowest on the market for a tractor-drawn hook lift trailer system with full container capacity.
- What is the difference between exchange position and travelling position?
- In exchange position, the chassis is fully lowered onto the axles via hydraulic suspension. In travelling position, the chassis sits approximately 70–100 mm higher. MetaFlex suspension has a total travel of 350 mm.
- What is rollover angle and why does it matter?
- The rollover angle is the lateral tilt at which the vehicle begins to tip over. It is calculated as arctan(half track width ÷ centre of gravity height). Lower build height means a lower centre of gravity and therefore a higher rollover angle – the vehicle can handle steeper slopes and tighter corners before tipping risk increases.
- Why is low build height important for exchange safety?
- Lower build height produces a flatter exchange angle, distributing forces more evenly and reducing the risk of materials sliding off. The geometry becomes stronger and safer with every exchange.
- How does tyre size affect build height?
- Larger tyres raise build height directly – every mm of extra tyre radius is one mm of extra build height. With free tyre choice, MetaFlex can be optimised for either lowest build height or maximum ground clearance.
- Can the tractor's drawbar height affect build height?
- Yes – a high drawbar tilts the trailer rearward and increases the effective build height at the rear. Drawbar height should always be specified when taking exact measurements.
- Does the 4.5 metre rule apply throughout the EU?
- No – Sweden and certain EU countries such as Finland permit 4.5 metres. Many other EU countries apply a 4.0 metre maximum. Always check local regulations for the country in which transport takes place.
- Why are Metsjö's hook lift trailers lower than competitors'?
- Metsjö integrates the hook lift system directly into the chassis rather than mounting it on top of a standard frame. Combined with telescopic cylinders with low installation height, an optimised main beam in high-strength steel and a hydraulic lowering function, this delivers a build height that is difficult to match.
Want to know which MetaFlex configuration optimises your transport operations?
Contact our experts or configure your own trailer at metsjo.se.