A custom strut order usually goes wrong in one of three places – the measurements are off, the force is guessed, or the end fittings are assumed. If you are working out how to order custom struts for a canopy, toolbox, hatch, machine guard or marine locker, getting those basics right saves rework, delays and unsafe operation.
Custom struts are not complicated, but they are specific. A strut that is close enough on paper can still overextend, underperform or put too much load into hinges and mounts. That matters whether you are replacing a failed pair on a caravan door or specifying a new setup for industrial equipment.
How to order custom struts without guesswork
The fastest way to get the right result is to treat the order like a fitment job, not a generic parts purchase. The more accurate the application details, the easier it is to match length, force, stroke and hardware.
Start with the application itself. What is the strut lifting, supporting or controlling? A bonnet, side-opening toolbox lid, heavy machinery cover and cabin seat base may all use petrol struts, but they do not behave the same way. Mounting angle, lid weight, hinge position, opening travel and environmental conditions all affect the final specification.
If you are replacing an existing strut, record everything printed on the old unit if it is still legible. Part numbers, force in Newtons, extended length and brand markings can all help. Even then, do not rely on the label alone. Previous struts are sometimes incorrect, substituted or fitted to compensate for another issue.
If it is a new application, measurements and operating details become even more important. In most cases, a specialist can work from clear dimensions and photos, but those inputs need to be consistent.
The measurements you need before ordering
The key dimensions are usually extended length, compressed length and stroke. Extended length is measured centre-to-centre between the mounting points when the strut is fully open. Compressed length is measured the same way when closed. Stroke is the difference between the two.
That sounds simple, but measuring the body of the strut instead of the full centre-to-centre mounting length is a common mistake. Another is measuring the strut while it is still installed under load and not fully opened or closed. For a proper custom order, you want the real geometry of the application, not an estimate.
You also need to identify the end fittings. Ball sockets, eyelets, forks and clevis ends are not interchangeable unless the mounts are changed as well. Thread size matters too. A strut with the correct force and length can still be unusable if the fittings do not suit the brackets.
Photos help here, especially if they show both mounting ends, the full open position and the full closed position. For trade and industrial buyers, a quick site photo often clears up more than a written description.
Measure from centre to centre
This is worth repeating because it causes a lot of ordering errors. On most petrol struts, the working length is taken from the centre of one mounting point to the centre of the other. Not body length. Not rod length. Not overall metal length without fittings.
If one fitting is changed, the effective length may change too. That is why the full fitting type should always be confirmed as part of the order.
Check closed clearance
A strut may fit perfectly when open and still bottom out when the panel closes. Closed clearance is especially important on low-profile lids, compact cabinets and machinery guards where space is limited. If the compressed length is too long, something has to give, and it is usually the mounting points or the panel itself.
Force rating is where many orders fail
The correct force is not just about how heavy the lid or panel is. It also depends on where the hinges sit, where the struts mount, how many struts are used, and the angle they work through.
This is why copying the weight of the panel into an enquiry is helpful but not enough on its own. A 20 kg lid mounted close to the hinge behaves differently from the same lid with the strut mounted further out. The opening angle changes the effective force requirement as well.
If you are replacing a strut and the old one worked properly before it wore out, the printed Newton rating is a good starting point. If the old strut never held correctly, forced the lid up too aggressively, or required too much effort to close, that rating may need to change.
For new applications, it is usually best to provide dimensions, mounting points and lid weight so the force can be specified properly. Guessing high is not safer. An overpowered strut can twist hinges, crack fibreglass, distort aluminium lids or make closing unsafe. Too little force is obviously a problem too, especially on heavy hatches and access covers.
Tell the supplier how the strut will be used
A petrol strut for a weekend camper trailer and one for a mining or marine application may look similar, but service conditions can be very different. Heat, dust, salt exposure, washdown requirements and cycle frequency all matter.
If the strut is fitted near the coast, on a boat, or in a corrosive environment, materials and finish should be considered early. If it is on plant or industrial equipment that opens and closes constantly, duty cycle matters. If it supports a safety-critical access panel, controlled movement and reliable holding force matter more than simply matching dimensions.
This is where a proper custom enquiry saves time. You are not just ordering a size. You are specifying how the part needs to perform in service.
What to include in a custom strut enquiry
If you want a quote turned around quickly, provide the basic technical details up front. The best enquiries usually include the application, whether it is a replacement or a new setup, the extended and compressed lengths, the end fitting types, the force if known, and clear photos.
It also helps to note whether you need one strut or a pair, whether left and right units differ, and whether brackets are required. On vehicle, caravan and toolbox jobs, mention if the mounting points are original or modified. On industrial jobs, note the panel weight, opening angle and any site constraints.
If you do not know the exact force, say so. That is better than entering a guessed number that sends the quote down the wrong path.
Replacement job or new design – the process differs
When ordering a replacement, the goal is usually to match an existing working specification or improve on one that failed prematurely. In that case, the old strut gives you a reference point, but the application should still be checked. If brackets have shifted, hinges have worn, or a lid has been modified, a straight copy may not be right.
For a new design, there is more calculation involved. The supplier may need mounting geometry, panel dimensions and weight distribution to recommend the correct force and placement. This is common on custom canopies, plant guards, cabinets, access doors and marine compartments.
Neither approach is better. They just require different information.
Common mistakes when ordering custom struts
Most problems are avoidable. People often measure the wrong points, assume the force from a similar-looking strut, or forget to mention that the application uses two struts sharing the load. Another common issue is not accounting for the rod orientation or the actual opening angle needed.
There is also the temptation to over-spec the force because the old struts feel weak. Worn struts do lose pressure over time, but that does not mean the original force was wrong. It may simply mean they have reached the end of service life.
On custom lids and hatches, bracket position is another variable. Moving a mount by even a small amount can change how the strut behaves through the arc. If the order is based on planned mount locations rather than installed ones, make that clear.
Getting the best result the first time
If you want to know how to order custom struts efficiently, the short answer is this: give exact measurements, avoid guessing the force, and describe the job clearly. A specialist supplier can usually work through the rest much faster when the enquiry includes the real application details.
That matters when equipment is down, a vehicle hatch is unsafe, or a production job is waiting on the right hardware. For Australian buyers, fast turnaround is useful, but accuracy matters more because the wrong strut still costs time.
Petrol Struts supports both straightforward replacements and custom applications across vehicles, machinery, marine, agricultural and industrial use. Whether you are ordering one pair for a toolbox or specifying multiple units for equipment fitout, the best starting point is the same – clear dimensions, clear photos and a clear description of what the strut needs to do.
If you are unsure about one part of the spec, do not fill the gap with a guess. Send what you can measure properly, explain how the panel operates, and let the fitment be worked out from there.
