Most damage to pickup beds can be prevented with the right plastic bed liners. That's true because thick plastic material resists almost any sort of impact and just shrugs off scratches as well. But somewhat of a surprise, the liners themselves can cause trouble. Read on...
Water hiding beneath the liners is a sure spot for corrosion to get going and cause a real mess. Since drop in liners are not so easy to get in and out, inspection of drains may be neglected and that's the way this problem becomes a potential route to a ruined bed. There's more too.
Then there is the shaky moves and resulting noise. Ill-fitting drop in bed liners form surfaces for wind to get behind. Poor fits make for more sound maybe bordering on noise. And it may be noise that's at best a nuisance and maybe even a downright irritation. Poor fitting liners are often more trouble than the liner is worth in both irritation and trouble.
There's more than just the noise too for sure. It's a wearing issue. A constantly shifting liner may very well wear away paint and that leads to real trouble.
The liner hides any worn spots and so the looks are not the problem, it's the bare paint and what that can lead to. That means another place for rust to get a start. What should have been protection may cause serious harm instead.
Finally consider paying less than the best... A plastic liner is a good deal in several ways. It should be much less expensive than a spray on liner. Plastic liners are tough. Damage a plastic bed liner, which is hard to do, and the liners are easily replaced. Look for good fits and good drainage to get a really good deal.
Plastic bed liners take almost any sort of abuse without the least damage to the liner or the truck. So you need a good fit and drain spots easy to keep clear and checked too. Noise and trouble accompany a poor fit.
The DualLiner bed liner approach combines two methods of bed protection. That design from DualLiner may work better for many trucks.