If you’ve ever tied flat materials to your roof rack and hit the highway, you’ll know the sound, a loud, droning hum or whistle that vibrates through the whole vehicle. It’s one of the most annoying parts of carrying a load, and most people just put up with it.

You don’t have to. The StrapSlap method is a simple adjustment that can make a noticeable difference. Here’s how it works.

What Causes the Hum

Once you’re doing 100km/h or more, the strap running over your load starts to vibrate in the wind. That vibration creates a harmonic hum, what we call strap slap, and it carries straight through the vehicle. It’s most common with flat, sheet-style loads, where the strap sits exposed across a smooth surface and the airflow sets it humming.

The StrapSlap Method

The fix couldn’t be simpler: before you tie the strap down, put a single twist in it over the load.

That small twist changes how the strap sits and disrupts the airflow travelling across it, the airflow that would otherwise set up the hum. It stops the strap from vibrating cleanly in the wind, which is what kills the noise.

When It Works Best

The StrapSlap method is most effective on the loads that cause the most trouble:

• Sheet materials and flat panels
• Any smooth, broad load with the strap exposed across it
• Highway and everyday driving in typical Australian conditions

It’s a two-second adjustment that costs you nothing and can turn a droning, teeth-grating drive into a quiet one.

A Small Tweak, A Big Difference

Carrying materials on the roof shouldn’t mean putting up with wind hum the whole way. Next time you strap down a flat load, give the strap a twist before you cinch it down, it’s one of those small tricks that makes everyday driving a whole lot more pleasant.