An attention-grabbing field worker, thanks to the distinctive semi-trailer. The tractor is as bland as they come. I’d say this combination is mainly used to collect fruit from the growers and their cold stores. And not only because of the Conference pears promotion on the semi-trailer.
It looked a bit grimy, clearly indicating that rolling down the freeway and driving around in built-up areas isn’t its main job. Furthermore, the whole configuration says twisting, turning and maneuvering all day long. I’ll get back to that later.
The 2004 Pacton tridem axle semi-trailer chassis has a Chereau temperature-controlled body and a Dhollandia slider liftgate.
Six axles in total, this is a 50 (metric) tons Dutch big rig alright, regardless axle spacing and the front axle’s maximum axle load.
That’s too heavy for the surrounding countries though. You’ll have to unload ten tons of pears before crossing the German border. Or six tons of apples when going to Belgium and another four tons when driving further south, into France. Nothing wrong with comparing apples and pears, in these calculation examples.
Anyway, the weight distribution is just perfect, either with a partial or full load. Only the tractor’s drive axle and the semi-trailer’s second axle are non-steering axles.
I did a quick chassis scan, the Pacton seemed to have a Tridec TD-X steering system. That’s a mechanical, rod-controlled steering system on the first and third semi-trailer axle, all directed by the tractor’s fifth wheel coupling.
Legal maximum weight and legal maximum overall length, combined with maneuverability. That’s what it’s all about when collecting heavy produce in rural areas.
Back to the front end. The tractor is a 2011 Renault Premium with a 470 hp, 10.8 liter inline-six. Although it does have a sleeper cab with a raised roof, the Premium is not a top segment model, specifically designed for the long haul. It was introduced in 1996 and evolved into the current Renault D-Wide, the cab of which is also used by parent company Volvo for their FE-series.
Question for the commentariat: I never see similar multi-wheeled steering semis here in the US. Is that due to regulatory issues, or the extra cost combined with a relative lack of need? Or just habit/inertia?
At any rate, as a mechanical engineer I find all of Johannes’ posts fascinating. Thanks!
It’s always about the lowest cost solution for the given circumstances and regulations. In Europe, these semis have to be able to navigate very tight street corners and curves. In the US, our roads and streets are laid out more expansively, and semi trucks stay away from the really dense areas. It’s also why COE trucks are not used here, as the length regulations are more generous here than in Europe.
The steering system on these trailers is undoubtedly not cheap. But it’s necessary there.
Definitely haven’t seen any forced steering trailers in my area, but self steering drop axles are definitely around.
However as Johannes mentioned about what the subject truck could be loaded to if it was going to different countries, here in the US a lot of the weight laws are still left to the states.
So you get region specific equipment. This company for example has a couple of “Northwest Super Chassis” specifically designed to run at 105,500 and meet bridge formula laws for axle loading and spacing. http://www.chassisking.com/products/northwest-super-chassis/
This one is the slider version so the rear axles can be slid back to meet the bridge formula laws, or slid forward to dock.
Now if you live where the weight limit is 80k then you probably don’t see many trailers with more than two axles, nor trucks with more than three.
For Dump and a Pup or Transfer Dumps below is a fairly common set up. Note the tongue on the Pup is adjustable on the fly, stretched out for on the road or dumping and compressed for making it around tight corners.
It can be disconcerting to the driver sitting at a light behind one of these when the driver determines he needs to shorten up to make it around the corner. Back up lights and beepers start, but the trailer has had the air dumped to the brakes and the pin actuator released so the trailer stays still and the truck backs down the tongue. Air is restored, the brakes released and the pin clicks down securing the tongue in the short configuration.
Interesting. Might explain something I noticed this summer. Here in New England most large dumps are what is at least locally known as triaxles. So Normal front steering axle then three tandem axles under the load with the one nearest the cab liftable. When I was in VA most of the dumps had the same double tandem axle but instead of the third liftable unit the often had 2 or 3 smaller axles with single tires. I’m guessing that must be to meet some per axle loading requirement.
Here’s a North American big rig with a Dutch (electronic) VSE steering system on the semi-trailer. In this case, the second and third axle of the tridem are steering.
Other (proven) advantages, besides maneuverability: less tire and pavement wear, less stress on suspension and chassis.
I’m surprised that the regulations differ across borders; I assumed that in the EU or at least Benelux neighbors that would be seamless. Although I generally think the similar state variations in regulations here in the US are silly, on the other hand it’s good to see some autonomy in an increasingly homogenous world. Though these enclosed trailers dedicated to produce are rare here, so living in a heavily agricultural area with mild weather, I enjoy seeing flatbed trucks with open crates of fruits and vegetables, or even giant uncovered tomato or sugar beet bins, with the opportunity to see first-hand what’s in harvest.
Yeah lots of variances between states in the US. Here in the PNW trucks can go up to 105,500 w/o an over weight permit, with the right equipment of course. While in many states 80k is max w/o a special permit.
In OR triples are legal so trucking companies have make up and break up yards near the boarder where they will break down triples into doubles and vice-versa depending on which direction they are traveling. While in the North East you have make up and break up yards for going from doubles to singles and back again.
Maybe it’s an optical illusion, but it looks to me like the (lack of) distance between the cab and the trailer would limit articulation. US tractor trailers usually have several feet between the cab and the trailer.
The cab is as close to the semi-trailer as possible, no articulation limit though. Also, the cab’s side spoilers might give you an idea of optical illusion.
Presumably the advantage of electronic trailer steering is that it can be adjusted without regard to movement of the tractor? Otherwise seems an expensiveor complex way of doing what a simple (if ingenious) mechanical system can do.
I don’t think steerable trailers exist here in Oz, but perhaps our Mr KiwiBryce might know better.
Look around here a bit:
https://www.v-s-e.com/steering-systems