When should loading dock bumpers be replaced?

Dock bumpers take a hit every time a trailer backs in. Here is how to tell when one is done, what wears them out, and what to replace them with.

Signs a dock bumper needs replacing

• Half the rubber is gone. Loading Systems advises replacing a bumper once it is about 50% worn, or when the face shows deep grooves or wears unevenly.
• The rubber is flush with the steel. On a laminated bumper, the rubber pads should stand out past the steel angles that hold them. Once the pads are worn back to the steel, the trailer hits metal.
• Bent, torn or rusted steel. A bent angle or a rusted frame can no longer hold the pads, and bare metal grinding on the trailer damages both.
• Loose or pulling anchors. If the bolts move or the bumper shifts when you push it, the impact is going into the anchors and the concrete around them.
• Cracked or crumbling concrete. Broken concrete around the bumper or along the dock face means the wall has been taking hits. The bumper needs to be replaced, and the concrete may need repair before new anchors will hold.
• Wear on one side only. Uneven wear usually means trailers are backing in off center. Replace the bumper and look at the approach, the striping or the trailer guides.

What wears dock bumpers out

Every trailer that backs in presses the bumper, and the trailer keeps moving a little while it is loaded. Each time a forklift drives on and off, the trailer bed rises and falls and rubs the bumper face. That friction, called trailer creep, grinds the rubber down even when nobody backs in hard. Busy docks, heavy loads and trailers with air ride suspension wear bumpers faster.

What happens if you wait

A good bumper absorbs most of the impact. Loading Systems puts it at more than 80% of the impact force for a bumper in good condition and less than 15% for a worn one. The rest goes into the dock face, the leveler lip, the door frame and the trailer. Waiting turns a bumper swap into concrete repair, a damaged leveler or a bent door track.

Which bumper to replace it with

Most bumpers fall into four types.

Bumper type	Where it fits
Laminated rubber	The standard bumper for semi trailers. Made from layers of recycled truck tire held between steel angles.
Steel faced	Docks with heavy traffic, air ride trailers or yard trucks. The steel face stands up to rubbing better, though it gives a little less cushion.
Molded rubber	Light duty docks for delivery vans and box trucks. Not meant for steady semi traffic.
Extruded rubber	Rub rails and column guards inside the building. Not for trailer impact.

Loading Dock Supply gives typical service lives of about 1 to 3 years for molded bumpers, 7 to 10 years for laminated bumpers at a medium traffic dock, and 10 to 15 years for steel faced bumpers at a busy one. Your own traffic sets the real number, which is why inspection matters more than age.

Size, height and spacing

A standard bay uses two bumpers, one on each side of the door. A common laminated bumper sticks out about 4.5 inches from the wall. Taller vertical bumpers suit docks that see trailers of different heights, or docks where the trailer bed rides above the bumper. When you replace a bumper, match the old one's thickness unless the trailers have been hitting the wall above it. If the driveway slopes down to the dock, the bumpers usually need to stick out farther so the top of the trailer does not reach the wall first.

How often to inspect bumpers

Look at your bumpers at least twice a year, and every three months at a busy dock. Check the rubber, the steel angles, the anchors and the concrete around them. A good time to do it is when the dock leveler, the dock seals and the overhead doors are serviced, so one visit covers the whole dock.

Replacing a bumper

A new bumper is bolted to sound concrete with heavy anchors. Old holes are often worn or cracked, so new holes go into solid concrete beside them. Bumpers mounted on block walls need the block filled with concrete first. If the concrete itself is broken, it is repaired before the new bumper goes on, or the new anchors will pull out the same way.

Common questions about dock bumpers

How far apart should dock bumpers be placed?

For a standard 8 or 9 foot dock door, the two bumpers usually sit one on each side of the opening, about 96 inches apart measured center to center, according to Loading Dock Supply. That spacing puts both bumpers under the rear frame of a trailer. Docks that see trucks of mixed sizes often add a third, horizontal bumper in the middle.

What are the best dock bumpers?

The best bumper is the one that matches the traffic. Laminated rubber suits most semi trailer docks. Steel faced bumpers last longer at busy docks and with air ride trailers, which rub harder as they rise and fall. Molded rubber is fine for vans and light trucks. Picking a bumper that is too light for the traffic is the most common reason one wears out early.

Why do laminated bumpers crack or show wire?

Laminated bumpers are cut from layers of truck tire, and tires carry steel or fabric cords. As the rubber wears down, those cords show at the face, and an old or cheap bumper can split between the layers. Exposed wire or cracks between the layers are a sign the bumper is near the end of its life.

When should I use extra tall dock bumpers?

Use taller vertical bumpers when the dock serves trailers and trucks of different bed heights, or when trailers ride high enough that their frame clears a standard bumper and hits the wall. A taller bumper covers the whole range so every vehicle meets rubber, not concrete.

How G Brothers helps

We repair and replace dock bumpers, along with dock levelers, dock seals and the loading dock doors above them, for warehouses and businesses across the Denver metro, including Lakewood, Denver, Arvada and Wheat Ridge. We dispatch 24/7 when a dock is down, and can provide a certificate of insurance, usually within 24 hours. See dock leveler, seal and bumper repair and loading dock door repair, read when to replace loading dock seals and why a hydraulic dock leveler stops working, call (720) 421-6489, or ask for a free estimate.

Sources

• Loading Systems, When to replace dock bumpers? Read our tips and tricks
• Loading Dock Supply, Dock Bumper Selection and Installation Guide