This Is Why Truck Trailers Have Quilted Rear Doors: A Brief Explainer (Update: Details From The Manufacturer)

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Photo: Jalopnik / José Rodríguez Jr.
Truck YeahThe trucks are good!

Semi trucks and their trailers are our stalwart friends on any road trip. Those who spend a lot of time driving can attest that the highway is the natural habitat of these hulking machines. But even if we see them all the time, a lot about trucks is a bit of a mystery to us outside of that world, and one of these mysteries caught my attention a few days ago: quilted rear doors.

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If you want to be specific, these are “diamond pattern stainless steel doors” according to Utility Trailer, the manufacturer. The reason they look that way is simple yet pretty clever: The quilted steel stops light from reflecting directly backwards. It breaks bright reflections and angles them away from drivers.

That’s right. Truck drivers and tractor trailers are actually more considerate than the cursed bunch of drivers who cruise around with HID lights that are not properly dialed in for road use, and inevitably end up damn-near blinding the rest of us.

The quilted — or diamond — doors are optional on both dry vans and refrigerated trailers. They seem to be more commonly used on the refrigerated kind, also known as reefers. And this is how Utility describes the unique finish:

Diamond Pattern Stainless Steel Door Skin -

Door skin is easy to clean and resists corrosion, while the high gloss quilted design presents a unique appearance and reduces glare to following vehicles.

The trailer maker talks up the cleanliness, which you can imagine is important for a trailer that will see years of service and travel thousands of miles, but the bit about glare is just as important. Just look at the default door on the dry vans to see what a difference the quilted finish makes:

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Screenshot: Utility Trailer
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Come on! That is glare city! I would not want to be drafting behind that truck if I was hypermiling.

You can see from that image how clever the diamond pattern really is, and since the short video I linked above may not show off the light-fighting properties that well, I want to show you this photo which I snapped just north of the border where trucks are constantly rumbling around:

Illustration for article titled This Is Why Truck Trailers Have Quilted Rear Doors: A Brief Explainer (Update: Details From The Manufacturer)
Photo: Jalopnik / José Rodríguez Jr.
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That photo was taken when the sun was directly behind us, yet there’s no glare! The thing is, this brings up the question as to why all rear trailer doors don’t have the same finish.

Wouldn’t it make sense to provide that quilted pattern on all trailers, period? That’s a question I’ve asked Utility but have yet to receive an answer. I will update if I hear back.

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UPDATE [Tuesday, April 06, 2021, 05:22 PM ET]: 

Utility Trailer has responded and confirmed the information from its website. The maker cited cost as the main reason all trailers don’t come with the quilted pattern. It comes down to money, but the price is less than you might expect.

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According to a spokesperson from Utility, the option can run anywhere from $800 to $1,000 on dry vans. It’s not common, however, for the quilted doors to be optioned by themselves. Companies usually order a high-spec trim which has aluminum wheels, chrome trailer bits and quilted stainless doors. That package runs from $3,000 to $4,000 extra.

The cheaper, white default doors on dry vans do a decent job with reflections, and they are much better at absorbing light than steel finishes on older trailers. You can still see the classic stainless finish on some tankers, but because of their cylindrical construction, dangerous reflections are less of a concern.

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Staff Writer at Jalopnik. Periodista automotriz, Naturally Aspirated Stan.

DISCUSSION

rvincent1960
Times up, time to leave!

This seems like an odd answer to me. Sure stainless steel does not take paint well but if you just want to make it non reflecting then brushed satin finish is the way to go.

I worked for a while in my youth at a place that used this for the side doors on food vans. Their main reasons were, looks better and it has more rigidity than flat sheet. The quilting pattern stops the sheets flopping around between the frame members due to wind which reduces wear and stops the rivets working loose.

The machine that they used to make this was also used on painted aluminum sheet too for the cheaper vans. It had a roller with a dual spiral of thick wire wrapping around. The sheet stock came off a coil at one end of the machine and out the other quilted like this.