Take a seat, but not just any seat…

In Tech Topics, October 20197 MinutesBy NZ Trucking magazineOctober 29, 2019

You may think you‘re sitting pretty, but that‘s not always the case…

Not that long ago, little thought was given to designing a truck seat. These were often put together to suit the stature of drivers in the truck‘s country of origin. If you were lucky the seat may have come with a basic slide arrangement to move the entire seat back and forth – otherwise, one size had to fit all. Problems with seeing out the front window were solved by sitting on a cushion. Thankfully those days are behind us; truck manufacturers and aftermarket seat suppliers now spend hundreds of thousands of dollars annually researching optimum designs for seats.

Called Repetitive Drive Injury (RDI), research has clearly drawn a link between how we sit in a vehicle, the length of time we do this, and the number of work-related musculoskeletal disorders. Truck driving is high on the list of occupations where, due to the nature of the work environment, these disorders are common. They typically show up as back pain (especially in the lower back), stress, a stiff neck, and sore shoulders. Fatigue can also be linked to poor seating. A good seat must recognise that each person is a different size and shape and should try to accommodate these variances as well as possible.


When adjusted correctly, a good seat will allow the driver to reach the pedals and other critical controls easily and without the need to stretch their arms or legs. Gauges and warning lights should be easily seen and the driver should have a clear view through the front and side windows and to the rear view mirrors – again without stretching. A seat must be comfortable for the driver to sit in. Along with these points, a good seat will isolate the driver from external and truck-induced vibrations. Seats must also be easy to get onto and off from without strain or any danger of slipping. Along with many other aspects of the trucking industry, seat design and specification, and its link to injury prevention, should be one of the things recognised in the workplace health and safety plan.

What the law says
For heavy vehicles, including motorhomes, a seat that is fitted as original equipment during the vehicle‘s manufacture and prior to any modification is deemed to comply with New Zealand‘s seat rules. If the seat is replaced by another seat that can be fitted to the vehicle without any modification to the seat mounts, then that seat is also deemed to comply. If a replacement or new seat requires the original seat mountings, such as where it bolts onto the floor, to be modified, or if it requires new seat mountings, then the modification must be certified by a specialist heavy vehicle certifier with the HVEC ‘chassis‘ category. If you are replacing a seat that does not have seat belts attached to it, and the replacement seat does, then the seat mountings must be certified as suitable for seatbelts. This is a requirement even if the replacement seat can be fitted to the original seat mountings without modification. And remember, just because a truck does not have to be fitted with seat belts, it does not mean they don‘t have to be worn. If seatbelts are fitted they must be worn unless the driver has an exemption! Removing seatbelts to avoid wearing them is not an option.

Ensuring integrity is not compromised
After the driver themselves, the seat is the most important piece of equipment in the vehicle. When OEMs fit seats into their vehicles they are bolted to the floor or onto specialist brackets for an important reason. That is so that if the vehicle is in an accident, the seat does not come out of the floor; if this were to happen, seatbelt or no seatbelt, the result would not be a good one. Often, when seats are replaced in vehicles, the same brand or model of seat is not fitted. This is essentially illegal. What you are doing is toying with the engineering integrity of the floor to seat connection. If a substitute brand of seat is fitted instead of the OEM model, then the vehicle must be recertified by a registered engineer with the appropriate supporting paperwork. This extends to the seat, the mounting bracket [which must be certified from the manufacturer], and the installation. “We always recommend replacing seats like-for-like if possible.

However, if you choose to go down another route, make sure that you do your due diligence and all products supplied are certified, as well as the install, in order to stay as safe as possible on the road,” says Callum McKendry of Geemac Trading (NZ) Limited. Geemac is the local distributor of Isringhausen (ISRI) drivers‘ seats, which are standard equipment in the majority of trucks sold in New Zealand and Australia. The New Zealand bus and coach sectors are also big customers of ISRI, and Geemac is also the preferred supplier for KiwiRail. Geemac also owns subsidiary company Seats (NZ) Limited, making it New Zealand‘s largest driver and operator seat supplier.