The EPA’s SmartWay program has been promoting wide single tires/wheels over skinny double tires/wheels for long haul trucks, owing to the lower rolling resistance of this arrangement.
Question: Why have wide single tires/wheels only been promoted recently? More to the point, if they improve fuel economy, why do they require promotion by anyone - why haven’t truck manufacturers been fitting these to trucks for decades?
One of my daughter’s school mates is a long-haul trucker. He’s an owner-operator (owns one truck and contracts for loads).
I asked him this question and he says it’s a question of probabilities. With dual tires he can usually continue to his destination even after losing one to a failure. With single tires he would have to wait on a tire changing service to come out and fix it. For a huge company with 10,000 trucks, the probabilities of tire failure are low and they can accept a few missed deliveries to get a small “global” fuel mileage increase. For a single operator, the savings aren’t worth the risk of a missed delivery (some are contracted for specific times) and the unexpected expense. Remember, the savings accumulate. If the big company only saves $10 per truck per month, it still translates to over a million bucks annually in the owners’ pockets. For the single trucker it’s less than a subway sandwich per week. (Disclaimer: I don’t know exactly how much is saved by the new tires)
The trucking community in America is **very **conservative and resistant to change. Super singles have been the standard on trailers across Europe for decades for the reason’s described.
The conservatism is also seen in the resistance to automatic gearboxes (standard over here), the old fashioned appearance of the trucks (to us they look like they were all made in the 50s), and that, even in states where snow is rare, they cling on to double drive axles.
In part this can be explained by legislation - In Europe the overall length of a truck is regulated rather than just the trailer; we carry heavier loads, over shorter journeys, on more congested roads. The market here is very competitive and margins small, and fuel, taxes etc are much higher.
This looks wrong on two counts. 1. To drive with a flat tyre, even one of a pair, would be illegal and dangerous. 2. The self employed trucker will not usually own the trailer. It will either belong to his client, or be hired in for a particular job.
There would normally be a spare on the trailer, and a driver could certainly change a wheel if he had to.
Twin wheels are nearly always put on the drive axles of trucks. This is because they have more grip which is not needed on trailer wheels.
No, Bob, a driver can’t certainly change a wheel if he had to. A driver doesn’t carry the equipment to change a wheel with him. And any time I’ve seen a spare carried on a rig, it’s unmounted. To change a tire, a driver’s going to need a hydraulic jack, an impact wrench with the proper bit, tire irons, a replacement tire valve (because you change them when you change a tire), and that spray they use to help the bead seal. If a steer tire blows, you pull over as soon as you can, call in, and have it changed on site. If it’s a drive or trailer tire, you call in to the next place en route where you can have it changed.
Double wide tires and wheels are more expensive than the singles. I can see medium to large fleet owners shelling out the $$ for them, but not owner/operators. And there are some hydroplaning issues with doubles that aren’t there with singles.
Oh, and while trailer tires don’t pull, they do brake. So they do need some grip back there.
There have been hundreds of innovations in the last couple of decades and while some radical truckers and many in Europe adopt them, the vast majority of trucking companies and independents here would rather paint their rig pink with bunny ears than install the streamlining panels invented 20 years ago and just now becoming a common sight.
In the UK it is unusual for a driver to change a wheel, because of the health and safety issues and partly because, for weight reasons, they don’t usually carry a spare.
This changes for operators who operate across the EU and beyond. Getting someone out to change a wheel in Serbia is likely to take a long time and be expensive. The supplier won’t speak English, and will want paying in cash. Many transcontinental outfits carry two trailer wheels and one for the tractor unit. They take the payload hit in return for not being delayed and/or ripped off. I could also add that it would be am offence here which would attract a fine at the very least.
Note I said ‘wheels’. They carry the tyre on a rim, so all they need is a 10 tonne jack and a wheel brace with a bar for extra leverage.
The only way I would drive anything more than a few yards with a flat, is if I could raise the suspension and get it off the ground. Many trailer fires are caused when the driver was not aware that he had a flat and the tyre overheated due to friction. The tyre would also be likely to disintegrate and destroy the mudguards and possibly the air lines to the brakes.
My point about traction and grip, is that the drive wheels need it to transfer all that power, through one or two axles, to the ground. Of course all the wheels are needed for braking.
I saw on a recent thread on a truckers forum, that many operators in the USA won’t even fit night heaters in the trucks. These have been standard here since the 70s. Air con is also standard on most trucks.
I think AC is standard on most vehicles in the US, because few regions don’t have hot/humid times of the year. Truckers that drive long distances are certain to drive through heat and humidity. Work trucks might lack AC (from cheapitude or misplaced macho) but I think nearly all OTR trucks these days do.
I Saw some of these on some old rigs in the Pacific Northwest, in 1970 or so, they were in a museum.
BOB++, My brother is an OTR Trucker, neither he nor I have ever seen a truck without a heater. Or did you mean block heaters for the engine? Almost all trucks in the northern part of the USA have one or two of those. Times two on the AC for the trucks I have not seen one without AC since about 1975 or so.
Most trucks have at least one mounted spare tire on the trailer. BTW have any of you ever changed a tire on a big rig? I have. ITs a bugger! My brother has pneumatic jacks and tire wrenches. If the flat is on an outside dual, he just runs the inside dual onto a 4X6 chunk of wood (also used as a wheel chock when needed). This gets the outside tire up high enough to change it. This is why the new tires go on the inside. BTW: If the tire will hold air long enough to get the truck to a tire shop, then that is what is going to happen.
I think you misunderstand. All the trucks that I have driven in the last 40 years or so have been fitted with a heater which is independent of the engine, for use on cold nights, or when waiting for long periods on cold days. These heaters have a battery operated fan and burn diesel.
Yes I have changed a wheel on the side of the road, and yes, it is a bugger. Crawling underneath to get a heavy jack under the axle (with some timber under it to spread the load), ‘cracking’ the nuts by jumping on a piece of scaffold bar to give extra leverage, struggling to line a heavy (100lbs or so) wheel up with the studs, and then back on the scaffold bar to get them tight. Then, wet, dirty and sweating, you have to get back in and drive. The trick with using wood is OK, but no good if it’s the inside tyre that is flat.
A regular tubeless truck tire will not come apart if run flat. Sometimes a recap will. The old split rim tube type tires were the ones that came apart and started fires. You can run a tubeless tire hundreds of miles flat. Not good for it obviously but it will hold up.
I won’t argue that a quality tire, running with a dual mate, can go a ways without coming apart, but ANY tire run at low or now pressure for very long is going to overheat and shred. It’s not limited to recaps and retreads.
And that’s ONLY as a dual. If it’s a single, it will self-destruct within a few thousand feet at highway speeds.