Here is a picture, with an unidentified smiling Brazilian trucker.
Here are the wheels at full resolution.
These are very common in Brazil, and I asked once before, but did not get a definitive answer. So, when I was down there last week I took the opportunity to take a photo of one of these trucks so that we have something concrete to work with.
Sensors to let you know if a tire blows? They’re only in the back, where there are multiple tires, so blowing one wouldn’t be as immediately obvious as losing one of the front ones…
My guesses would be some sort of static discharge device, or some sort of odometer. One occasionally sees a device on truck hubs with a weight in it to keep it right-side-up and an odometer display to show how many times the wheel has rotated (presumably to keep track of when maintenance is needed). This might be a similar device, if one doesn’t trust the weighting to keep the odometer device right-side-up.
I bet it’s an automatic tire inflation system, like the ones written about here. The photograph is obviously of a totally different type of unit, but the similarities are very telling.
I thought about it being an inflation mechanism.
On trucks that I see with these tubes (including the one in the picture), there are tubes on all wheels, (even the front wheels).
I would buy that as an explanation if they weren’t so common. Why would a fancy auto-inflation mechanism be on every other João and José’s beater truck?
The odometer idea doesn’t make sense because they are on every wheel (unless there really is a need to measure each wheel’s travel).
Perhaps some different laws – some requirement there that we don’t have?
Maybe whatever those tubes do is not necessary in the US?
Maybe they are not approved by the US DOT, so we never see them?
Of course, I realize that I could have simply walked over to the fellow and asked…
But that’s not as much fun, is it?
Well, as a wild-eyed guess, I would suggest that they are brake actuation devices. As the truck slows, the load will shift, pulling up on the “tube”, and actuating the lever and actuating the bakes in step.
Hey…that’s my guess!
My guess is that they are manual tire inflation tubes. Why have such a thing in Brazil and not the U.S? I would guess that a lot of roads in Brazil aren’t paved. If you get stuck, the best way to increase your traction in such a truck would be to let air out of all the tires. This device would make it easier, especially if your truck was stuck up to the hubs. They didn’t appear to be hooked up to any kind of system. The driver probably uses the trucks air brake system to reinflate the tires after he gets it unstuck.
Or maybe truckstops with compressed air are much rarer in Brazil than in the United States. So it’s standard to equip the trucks with inflation devices that work off the airbrake system. In the United States truckers can count on always being able to find compressed air when they need it, but that might not be the case in Brazil.
Sorry but that doesn’t really make sense, Pochacco. Why do you need fancy tubes and hubs just to inflate tyres off the airbrake system? All you’d need is an air line to the regular ole’ valves, surely?
Regular Old valves tend to rotate along with the tires. Any auto-inflation device will have to route through the hub for this reason. I agree that they are not that common in the U.S. because most trucks have regular access to pneumatic air, and they are rather expensive to install. I have seen them on SOME trucks, and they are pretty common on military vehicles, although they look different. A google search on “trucks auto-inflation system” will bring you loads of info.
I see these on tourist-style busses in Mexico all the time. By this, I mean the non-municipal busses, but rather the city-to-city busses that are usually first class service. I’ve always asked myself this, too, i.e., what they hell are they. The thing is, they’re not on every tire on most busses. I can’t recall seeing them on cargo trucks, either, and I always associate them with busses.
Its called “rodoar”, is used to keep tires inflated
Kind of amazing that the OP’s links still work after almost 8 years…
Awesome, I looked up rodoar, and got this insightful response from Yahoo Answers
“Rodoar® monitora e mantém a pressão dos pneus mesmo com o veículo em movimento.”
Which I found surprisingly understandable even though I speaketh not a word of Portuguese.
And still there’s a huge “Proto-Indo-European is a myth”-movement.
That’s the power of cognates (words that look like their foreign-language equivalent) and imported words (i.e. croissant, sangfroid, etc.), though I doubt “imported words” is the correct technical term ( and I don’t have the time right now to look it up. )
I don’t know anything about that debate, but the Latin roots of Italian, Spanish, and Portuguese make those languages fairly easy to read for people who speak English. I do surprisingly well reading them with just a little background in Spanish and Portuguese. Of course speaking and comprehending them when spoken is a whole other matter.
Loanwords.
The thing that bothers me is that the device is out in the open and vulnerable to damage. If the truck threw a recap, it would certainly destroy it.
