Are magnetic signs legal for US DOT numbers?

Yes. 49 CFR 390.21T does not require permanent lettering. The marking has to contrast sharply, be readily legible in daylight from 50 feet, appear on both sides of the power unit and stay legible — a properly made magnet does all of that. It simply has to be on the truck while you are operating.

How thick should a truck magnet be?

We use 30 mil. The thinner 15 to 20 mil stock sold for car doors does not have the grip for highway speed on a large flat panel and it curls at the edges. Thicker stock also survives being pulled off and put back on every day.

Will they stay on at highway speed?

On clean, flat steel, yes. Wind gets under a magnet when the surface is curved, ribbed, dirty or freshly waxed, or when the corners are square. We cut rounded corners and size to the flat area for exactly that reason. Check them at fuel stops on a long run.

Will a magnet stick to my aluminum or fiberglass door?

No. Magnets only hold on steel. Plenty of newer vans, box bodies and some cab doors are aluminum or composite, and a magnet will slide right off. Send a photo before you order and we will tell you if it will not work.

Do magnets damage paint?

Not if you take them off and clean underneath. Trouble comes from leaving one in place for months: dirt and moisture get trapped, and the paint under the magnet ages differently from the paint around it. Pull them weekly, wipe both surfaces dry, put them back.

How should I store them?

Flat, face up, at room temperature. Rolling or folding a magnet puts a permanent kink in it, and a kink is exactly where the wind gets in.

How fast can I get a set?

Most sets are made the same day at our Rolling Meadows, IL shop. Not local? We ship them flat anywhere in the US.

What does a set cost?

It depends on the size, whether it is full-color print or cut lettering, and how many panels you need. Call or text your door size and what goes on it and you will have a price in minutes.

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SERVICE · MAGNETIC SIGNS

Magnetic Truck Signs

A magnetic sign carries your company name, USDOT number and phone on a removable panel that sticks to a flat steel door — on for the run, off when the truck goes back to personal use. We print and cut them on 30 mil magnet at our shop in Rolling Meadows, IL, most sets the same day, and ship anywhere in the US.

Call 224.400.0950 Get a quote

SHORT ANSWER

Magnets are the right call when the marking has to come off: a leased truck, a personal vehicle, seasonal work, or a name that is going to change. They are fully legal for USDOT markings as long as they meet the same test as painted lettering — sharp contrast, readable from 50 feet, on both sides while you operate. The catch is the surface: magnets hold on flat steel only. Send your name, your numbers and a photo of the door and you will have a price in minutes.

What you get

Full-color print or cut vinyl on 30 mil magnetic sheet — the thickness that actually holds at road speed
Sized to the flat area of your door, not trimmed down from a stock rectangle
Company name, USDOT and MC numbers, phone and website in one clean layout
Colors picked against your paint so the marking stays legible at distance
Rounded corners, so wind has nothing to lift
A matched pair for both doors, or single panels if that is all you need
UV-rated print that does not wash out to pink after one summer
A care sheet: how to pull them, clean under them and store them flat

What the rule says about magnets

FMCSA does not care whether the marking is paint, vinyl or a magnet. 49 CFR 390.21T applies the same test either way:

Magnets are allowed. Nothing in the rule requires permanent lettering. A removable panel is legal as long as it satisfies every other requirement.
Sharp contrast. The letters must contrast sharply with the panel behind them — and the panel has to read against the door.
Legible from 50 feet. Readily legible in daylight from 50 feet away, exactly the same standard as cut vinyl.
Both sides, and still attached. One on each side of the power unit, in place while you are operating. A magnet that blew off on the highway is an unmarked truck.
Kept legible. Faded, cracked or curling magnets are a violation the same way a half-scraped decal is.

The practical catch is not the regulation, it is the surface. Magnets hold on flat steel only — they will not stay on aluminum, fiberglass or composite panels, and a curved or ribbed door leaves gaps for wind to get underneath. Send a photo of the door and we will tell you straight whether a magnet is the right answer or you are better off with cut vinyl.

Straight from the source

How ordering works

1
Send us the details
Call, text or use the quote form with your company name, your USDOT and MC numbers, and the size of the flat area on the door. A photo answers most of our questions at once.
2
We lay it out
We set the type to fill the panel, size it to pass the 50-foot test and pick colors that stand off your paint. You approve the layout before anything runs.
3
Printed and cut
Printed or cut on 30 mil magnet, trimmed to your size with rounded corners.
4
Pick up or ship
Most sets are ready the same day in Rolling Meadows. We ship them flat anywhere in the US.

Design it yourself Read the install guide

Usually ordered with it

US DOT number decals

The compliant number set cut to spec — on the magnet, or straight on the door if the truck is staying yours.

Cut vinyl lettering

When the name is not changing, permanent vinyl costs less and never blows off.

Trailer decals and unit numbers

Big-format lettering for box trucks and trailers, where a magnet is not practical.

Fleet apparel

The same logo on shirts and hoodies for the crew.

Magnetic sign questions we get every day

Are magnetic signs legal for US DOT numbers?: Yes. 49 CFR 390.21T does not require permanent lettering. The marking has to contrast sharply, be readily legible in daylight from 50 feet, appear on both sides of the power unit and stay legible — a properly made magnet does all of that. It simply has to be on the truck while you are operating.
How thick should a truck magnet be?: We use 30 mil. The thinner 15 to 20 mil stock sold for car doors does not have the grip for highway speed on a large flat panel and it curls at the edges. Thicker stock also survives being pulled off and put back on every day.
Will they stay on at highway speed?: On clean, flat steel, yes. Wind gets under a magnet when the surface is curved, ribbed, dirty or freshly waxed, or when the corners are square. We cut rounded corners and size to the flat area for exactly that reason. Check them at fuel stops on a long run.
Will a magnet stick to my aluminum or fiberglass door?: No. Magnets only hold on steel. Plenty of newer vans, box bodies and some cab doors are aluminum or composite, and a magnet will slide right off. Send a photo before you order and we will tell you if it will not work.
Do magnets damage paint?: Not if you take them off and clean underneath. Trouble comes from leaving one in place for months: dirt and moisture get trapped, and the paint under the magnet ages differently from the paint around it. Pull them weekly, wipe both surfaces dry, put them back.
How should I store them?: Flat, face up, at room temperature. Rolling or folding a magnet puts a permanent kink in it, and a kink is exactly where the wind gets in.
How fast can I get a set?: Most sets are made the same day at our Rolling Meadows, IL shop. Not local? We ship them flat anywhere in the US.
What does a set cost?: It depends on the size, whether it is full-color print or cut lettering, and how many panels you need. Call or text your door size and what goes on it and you will have a price in minutes.

Read up before you order

Shop News & UpdatesMagnetic vs. Permanent Signs: Which Should You Choose?Swappable magnets or permanent vinyl lettering? Here is how to decide based on how your fleet actually works.US DOT & MC GuidesUS DOT Decal Requirements, ExplainedWhat every owner-operator needs to know about US DOT and MC number decals — size, placement and staying compliant on the road.How-To & Install TipsHow to Apply Vinyl Decals Bubble-FreeA shop-floor walkthrough for installing decals and lettering cleanly the first time — with the free squeegee we put in every order.

Get your magnetic signs today

Call or text your company name, your numbers and the size of the door — we will quote it in minutes. Mon–Fri 11 AM–5 PM in Rolling Meadows, IL, with nationwide shipping.

224.400.0950

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