A tonneau cover blowing open on the freeway can be a frightening experience. Not only does it look unseemly, but it can potentially damage cargo or allow debris to enter the bed. Fortunately, there are several steps truck owners can take to stop their tonneau covers from billowing open at highway speeds.
What Causes Tonneau Covers to Open on the Freeway?
Tonneau covers open on the freeway when the wind gets underneath the cover and lifts it. This is most common with soft roll-up covers but can also happen to hard folding covers under the right conditions. Here are some potential causes:
If the tonneau cover is not installed tightly and evenly, it can work itself loose over time. This allows wind to penetrate underneath and rip the cover open. Be sure to tighten all clamps, bolts, and tension adjusters evenly during installation.
Perimeter seals and gaskets are critical for keeping wind and rain from entering underneath a tonneau. But they deteriorate over time, allowing air to penetrate the bed and lift the cover. Inspect seals regularly and replace if cracked or missing.
Loose snaps, rails, or tension cables prevent the cover from maintaining a tight seal. This gives wind the chance to get underneath and lift up sections. Tighten or replace any loose hardware.
Some tonneau covers simply do not stand up well to highway speeds, regardless of condition. Soft roll-ups and low profile covers tend to be the most susceptible. Upgrading to a cover with a more rigid design may be required.
The faster your vehicle is traveling, the more forceful the wind becomes. At freeway speeds over 65 mph, the wind can generate enough force to overpower many tonneau cover designs. Slowing down may help reduce opening incidents.
How to Stop a Tonneau Cover From Opening on the Highway
If your tonneau cover constantly blows open on the freeway, here are some tips and tricks to try:
Inspect and Tighten Components
Carefully go over the entire cover and tighten any loose or worn hardware. Pay special attention to perimeter clamps, bolts, gaskets, and tension cables. Even minor looseness can allow the wind to penetrate and lift the cover.
Adjust Tension Settings
Many soft roll-up and tri-fold covers have tension knobs or cables that can be adjusted. Tighten these tensioners evenly on both sides to reduce cover flapping at speed. But be careful not to overtighten, which can damage components.
Clean and Treat the Vinyl
Use a vinyl protectant spray to keep tonneau cover vinyl conditioned and supple. Stiff, dry, cracked vinyl is more prone to catching the wind. Treat it regularly with protectant sprays to maintain proper flexibility.
Add Wind Stops
Some tonneau owners install small wind stops or deflectors along the cover’s perimeter. These prevent wind from rushing straight into the gaps between the cover and bed rails. Make sure they are evenly spaced and don’t interfere with operation.
Apply Adhesive Velcro
Adding industrial strength Velcro strips along the underside of vinyl covers can help keep them sealed tightly to the bed. The Velcro acts as an extra securing measure to minimize wind penetration. Just take care not to damage the truck’s paint when removing the cover.
Drive Slowly During High Winds
When driving through intense winds or storms, keep speeds below 55 mph to reduce force on the tonneau. Also, avoid driving beside large vehicles like semis whose wake can catch underneath the cover and cause it to open partially.
Upgrade to a More Rigid Cover
If the cover is in good shape but still opening, you may need to upgrade to a more rigid, wind-resistant design. Hard folding covers and retractable covers typically stand up to highway speeds better than basic roll-ups.
Remove the Cover Temporarily
If all else fails, the last resort may be removing the problematic tonneau cover when freeway driving is required. This prevents it from blowing open and eliminates any risk of cargo or cover damage from flapping at high speeds.
Key Maintenance Tips to Stop Tonneau Opening
Proper care and maintenance of your tonneau cover will improve wind resistance and help keep it closed. Here are some maintenance tips:
Keep Vinyl Clean and Flexible
Use a mild soap and water solution with a soft brush to gently clean tonneau vinyl. Avoid dish soaps or degreasers which can dry out the material. Treat it regularly with a high quality vinyl conditioner like 303 Aerospace Protectant.
Lubricate Hinges and Hardware
Keep hinges, clamps, and sliding rails lubricated with silicone spray or lithium grease. This prevents them from binding or sticking, allowing for a tighter seal. Wipe away any excess lubricant after application.
Inspect and Replace Seals
Examine the seals around the cover’s perimeter a few times per year. Look for gaps, cracks, brittleness, or damage. Deteriorated seals should be replaced right away to maintain a tight windproof seal.
Adjust Alignment if Needed
Over time, panels on folding and roll-up covers can slip out of alignment. This can put stress on seals. Realign any off-center opening panels and adjust the latching mechanisms for optimal seal.
Use Protective Storage When Not in Use
Don’t leave vinyl tonneaus exposed to sun and weather when not on your truck. Use a breathable vinyl cover or store in a garage to protect from UV damage, bird droppings, sap, and dust accumulation.
Wash After Trips and Weekly
Wash your tonneau at least weekly and after any dirt or salt road trips to prevent buildup of debris around seals. Hand wash with a mild soap and water solution. Rinse thoroughly and wipe dry.
Signs Your Tonneau Needs Adjustment or Replacement
Here are some common signs that your tonneau cover needs maintenance or replacement to stop it from opening on the freeway:
- Vinyl cover has become stiff, misshapen, cracked, or puckered
- Perimeter seals are cracked, brittle, loose, or missing sections
- The cover is sagging in places or has uneven gaps
- Snaps, bows, or tension cables are bent, loose, or broken
- Hinges squeak or stick and don’t open/close smoothly
- Sections of the cover flap or billow at highway speeds
- There is interior water leakage during car washes or rain
- The cover makes loud whistling or flapping sounds while driving
Don’t ignore these signs of wear. Address issues promptly by cleaning, adjusting, lubricating, tightening, or replacing components as needed to keep your cover wind and water tight.
When to Consider a New Tonneau Cover
If your current tonneau cover continues popping open on the freeway after thorough inspection, adjustment, cleaning, and maintenance, it may be time for a new cover.
Consider upgrading to a more rigid, hard folding design or smooth operating retractable cover. Both of these provide increased wind resistance.
Finally, if the cover’s vinyl or main components are simply too deteriorated and loose to tighten back up properly, replacement will be required to stop the flapping.
Investing in a higher quality tonneau cover from a reputable brand can also increase durability and highway stability. Do your research to find secure, wind-tight covers with strong owner reviews.
A tonneau cover opening repeatedly on the highway can be a nuisance and safety concern. In most cases, the issue can be resolved through proper installation, maintenance, tensioning adjustment, and upgrading worn components if needed. For tonneaus in poor condition, replacement may be the best solution for eliminating annoying freeway flapping. With some attention and care, your cover will once again close tightly to keep your truck bed protected from winds, rain, and debris.