What Are The Plastic Strips On Truck Wheels For?

If you don't drive a truck yourself, some incidental elements about tractor trailers can seem strange or unnecessary to you, like the high number of side-view mirrors around the cabin or the mildly menacing spikes jutting out of their wheels. Every component of a truck is definitely there for a reason, even if you can't immediately tell what it is as an outside observer. For example, have you ever been driving next to a truck on the highway, and noticed that one or more of its wheels have long plastic strips dangling off of them? It's definitely not the kind of thing with an obvious purpose; why would you need to have a long tag sticking out of the middle of the wheel like that? Is it a handle, or perhaps some means of identification like an ID tag?

Neither of those are quite right, though the latter hypothesis is actually a little bit closer. The plastic tags are a means of identification, though rather than any form of ID or sorting, what they're identifying is whether or not the tire is actually rotating. The purpose of a plastic strip on a truck wheel is to give the driver an easy means of verifying the wheel's rotation that they can see from the cabin.

An occasional problem that truck drivers have to deal with is locking wheels. Due to the heavy weight of a truck and the particular function of its air brakes, it's possible for the springs in the braking system to get frozen, especially if they're old and worn out, causing a wheel to stop spinning.

If you're driving in a regular car and one of your wheels suddenly locks up, you'd probably notice it pretty quickly. In a large 18-wheeler truck, though, things are different. Even if one wheel stops spinning entirely, there are still 17 other wheels moving the truck forward. This results in the stopped wheel getting dragged down the road for miles on end, leading to intense wear and possibly blowout. Even if the driver can see the wheel in their side-view mirror, it can be very difficult to determine if it's spinning or stationary at a glance.

This brings us to the plastic strip. By attaching a plastic strip to one of the wheel's lug nuts, you create an easily-identifiable marker that can be seen moving from the cabin's side-view mirror. If you can see that the tag has completely stopped, you know that the wheel it's attached to is locked up. With that, you can quickly get off the road and fix the problem before it gets worse.