"reverse" spoiler on trailer ?

[Underscore_101_3]

Was doing some research for some AI paint jobs and came across this:
https://flic.kr/p/fcN6AP

Is the upside down spoiler in front of the trailer's wheels a common thing?
And what is it for..? to reduce whatstheword,.... pressure for lack of a better word,... on the road?

Have seen hundreds of american trailer images, but never that, so far :-)

[HighPlains Drifter]

I'd assume it's to reduce drag on that rear tire carriage... But i've never seen one like that/done that way.

[Dark & Realistic™ Nessie]

I've never saw one like that. Hopefully someone will appear to explain this, but my lack of knowledge makes it look like someone installed something wrong for me... 🤣

[Wolfgang]

Tbh, when I saw this the first time my brain went to "Snow plow for... uuuhhh... huh.", so I have no clue.

[Qrazy]

I've seen all kinds of things on trailers to reduce drag and improve MPG. But I've never seen one that like before.

[Underscore_101_3]

Thanks for the replies so far, guess the word I was looking for was drag, it does make some sense, but I guess if it was really benificial it would be more common.

[Supernovae]

It's possible funneling the air down reduces turbulence around the tires. There are quite a few aero devices that seem somewhat uncommon in the trucking industry so just because it's unique doesn't indicate it's automatically kinda useless. Looks like an "improved" air dam to better control the airflow. Typically you'd have the air dam at the front of the vehicle to minimise air going under, but in this case it would accelerate the airspeed under the trailer and around the wheels which may have a positive effect on fuel economy.

[_KC76_]

Or it might just be a DIY customization to match the tractor Spoiler ..

[Dark & Realistic™ Nessie]

Originally posted by Supernovae:

It's possible funneling the air down reduces turbulence around the tires. There are quite a few aero devices that seem somewhat uncommon in the trucking industry so just because it's unique doesn't indicate it's automatically kinda useless. Looks like an "improved" air dam to better control the airflow. Typically you'd have the air dam at the front of the vehicle to minimise air going under, but in this case it would accelerate the airspeed under the trailer and around the wheels which may have a positive effect on fuel economy.

I'll assume this one as the correct answer. It sounds more technical and plausible than what I thought.

[Underscore_101_3]

Though it does make sense, I'm not fully satisfied yet :-)

[Devil]

it looks like a useless DIY wind deflector on an owner operated tractor trailer.

[mojo_musica]

Originally posted by Underscore_101_3:

Though it does make sense, I'm not fully satisfied yet :-)

I have seen plenty of Swift and other companies trailers with a central wind deflector under the trailer that flares out in front of the back axles, not exactly the same, but definitely trying to smooth airflow behind the tractor. Maybe this is a one-off custom addition?

[Reese]

When I was reading the summary while hovering, I was so lost. Looking at the picture, I'm even more lost. As a tractor-trailer PM guy, I've NEVER seen one like that in that position. Usually it's much larger going halfway up the trailer: https://www.ttnews.com/sites/default/files/styles/article_full_width_image/public/images/articles/aero-ekostinger-blue-stinger-0518.jpg
Or https://nap.nationalacademies.org/openbook/18736/xhtml/images/p79-02.jpg

Some of these are problematic when doing a PM, or even just trying to get a jack under it, especially in rain/snow. They are very uncommon in the US, so I don't have much information on them from experience.

I have recently acquired information that a certain percentage of trailers in a fleet must have some sort of drag reduction/fuel economy modifications to run in California. Neat.

Edit: But yeah most definitely to reduce drag for fuel economy. How well it works, probably not proven. Seeing their axles all the way forward with chrome all around, likely drives into Cali quite a lot. Actually it looks like they have their entire fleet set up that way. Woah.

[Underscore_101_3]

I think I'm satisfied now :-)

Thanks for all the replies and time put in it.

[Dark & Realistic™ Nessie]

Originally posted by Reese:

(snipped)

That's my other correct answer now. 😁