Tonneau Cover Rattle or Flapping: How to Find and Fix It

Most tonneau noise is something moving. A rattle or a clunk over bumps is hard parts touching. Flapping, or a drumming flutter that builds with speed, is wind working slack vinyl. A whistle is air moving across an edge, often the edge of a stack folded at the cab. Name the noise and you've narrowed the cause.

Most of the fixes are free. A Tyger soft roll-up that flapped and billowed above 60 mph went quiet at 75 once the top was pulled hard and re-tightened, and its owner had been ready to give up on it for a hard cover.

Rule out the truck before you blame the cover. Rack crossbars can rattle in their towers, a soft cover's spare support bows rattle loose on the bed floor, and a drain tube left long can slap the cab. On one F-150 Lightning, a plastic drop-in liner had to be modified to fit the cover's brackets, the power tailgate then needed a push to close, and backing the cover off to give the gate room just made it rattle.

Where the noise comes from, by cover type

Each style has its own noisy parts. Find yours below and start there.

Hard folders include the BAKFlip MX4, the UnderCover Ultra Flex and the LEER HF650M. The TruXedo Sentry CT and BAK Revolver X4s are hard roll-ups, the RetraxPRO XR and RetraxONE XR are retractables, and the TruXedo Lo Pro and Tyger T3 are soft covers.

Soft covers make the most noise, and almost all of it is flapping at highway speed. Some flutter is normal: soft-cover vinyl can ripple in the mirror without a sound in the cab. A drumming you can hear over the radio is not, and it means the cover needs tension.

Find it: drive it, then check it parked

Find the source before you buy anything. A couple of drives and a walk around the truck usually do it.

1. Empty the bed. Take out loose tools, ratchet straps, spare bows and anything that can slide. A socket rolling around under the cover can sound just like the cover.
2. Drive it with a passenger listening. You drive at legal speeds; your passenger listens from a seat in the cab, once with the rear window shut and once with it open. Note the speed the noise starts and whether it follows bumps (hard parts) or speed and wind (vinyl or an edge). If your maker says the cover can be driven open, you can do one run with it opened and secured exactly as the instructions say, since that tells you whether the noise lives in the panels or the rails; skip that run if the instructions rule out the road you'd test on. Don't ride in the bed to listen, and never with the cover closed: BAK's Revolver sheet says that cover has no release from inside and warns never to let anyone be in the bed with it closed.
3. Push on everything. Parked, with the cover closed and latched, press down along each panel edge, the corners and the rails, and lift gently at the tailgate end. A panel that moves or clicks is your suspect. Look underneath for a clamp that has slipped down the rail, a missing rubber pad and a prop rod out of its clip.
4. Count the latches. Open the cover and close it again, and watch every latch engage. On a folding cover, check that each panel has one; some covers leave a panel unlatched by design.
5. Change one thing, then drive again. Fix the likeliest suspect alone so you know what worked. Change three things at once and the rattle that comes back in a month is a mystery.

Free fixes first: clamps, latches and rails

Start with the hardware. Loose clamps, latches and rails cost nothing to fix, so rule them out before you blame the design.

• Clamps. Check that each one is seated and tight. On a BAKFlip MX4 each clamp has to click up into a groove in the rail before the rail sits flush. Tighten to the figure on the install sheet and no further: BAK's sheet for its folding covers says not to overtighten, and its Revolver sheet warns that overtightening can warp the bed cap. Both sheets say to check every clamp for tightness after a week of driving and periodically after that.
• Square and latch. BAK's sheets say the cover's rails must sit square to the truck's bed rails so the rear latch engages properly; a rail that's off leaves the panels short of flush and the latches short of a bite. For a Tyger roll-up that won't latch, Tyger's FAQ says to pull the rails as close to the latch as you can, with no more than 1/16 in between them.
• Front to back. A hard roll-up sitting too far forward won't sit flush on the tailgate, and a cover that lifts at the front on the interstate is an install to check, not a noise to live with. The BAK Revolver X4s's hand nuts let you slide the cover back.
• The unlatched panel. The LEER HF650M's second panel from the rear has no latch of its own and can vibrate at highway speed. One owner adjusted it every way they could, couldn't stop it and returned the cover. The MX4 has the same cost-cut on a 6.5 ft bed, a hinge with no latch, though its owner calls it no big deal in use. If an unlatched panel is your noise, adjustment won't cure it.
• Missing pads and parts. Owners say the Revolver X4s uses rubber pads where the older X4 used felt, there to damp vibration and prevent pinching. Check they're all there when the cover arrives and raise a missing one with BAK right away: BAK won't sell parts outside a warranty claim, and an owner missing one rubber pad was told to buy a new cover.
• Drain tubes. Trim them long enough to clear the frame and no longer. Left flapping under the truck, highway wind can whip a tube against the cab. On a RetraxPRO XR, cut the hoses to length, and check that every screw is still in the canister.
• What rides on the rails. Rack towers and crossbars over a cover can rattle on their own. If you only use the rack now and then, take the towers off between trips. Don't crank the rack bolts to quiet them: Retrax replaced rails a PRO XR owner bent overtightening rack bolts.

Soft covers: tension, buckles and bows

A soft cover that flaps is a slack soft cover, and slack gets worse the longer you drive on it. The hook-and-loop along the rails holds the vinyl down, and it only holds as well as the pull on the vinyl.

• Pull it tight. Roll it closed, press the hook-and-loop down evenly along both rails and pull the vinyl tight. RealTruck says the TruXedo Lo Pro's spring tensioner keeps the vinyl tight at all times; in practice the sides can need pulling tight after you roll it closed, and a slack cover flaps on the highway. Tyger says the tension on its T1 roll-up adjusts at the ends of the side rails.
• Re-check with the weather. Vinyl tensioned on a cold day can loosen once the sun warms it. On a Vanish roll-up that brought on wind flutter, and a quick run down the hook-and-loop fixed it. Check the tension again a few weeks after install and whenever the seasons turn.
• Keep the hook-and-loop clean. Clean strips grip; dirty ones let the vinyl slip. A small brush clears them.
• Silence the buckles. Buckle straps that hold a rolled or folded cover at the cab can tap the bed or squeak on the rear window. Cinch them, and if a buckle still taps, a patch of hook-and-loop on the buckle and the cover holds it still. One owner did that on an older tri-fold; their current TruXedo soft roll-up uses straps with hooks instead of buckles.
• Get the bows out of the bed. Roll-ups with removable support bows leave them loose when the cover is rolled, and they rattle on the bed floor. Carry them in the cab or strap them down. Tyger's T1 builds its crossbars into the cover, so they roll up with it.

If it still drums after a proper tensioning, take it up with the maker before you give up on it. Water and noise share a cause here: a slack soft cover also pools water and sends it to the corners. Our guide to a leaking tonneau cover covers the seals.

Driving open: prop rods, straps and the folded stack

A folded or rolled cover is a different noise problem, because the stack at the cab catches the wind. Strap it the way the maker says, every time.

• Hard folders. BAK's sheet for its folding covers says to drive folded with the straps buckled at the bulkhead and pulled tight, and that the cover should have little to no movement once the prop rods are locked. The BAKFlip MX4's folded stack rests against the cab, leaning back toward the rear window, and its prop rods can pop off or fall out and the clips can break. The LEER's prop-rod clips are its flimsiest part; LEER will send new ones, and clips sold for hanging fishing poles make a sturdier swap. The UnderCover Ultra Flex stands its folded stack upright on prop rods, off the cab, RealTruck says it can be driven fully open, and Armor Flex covers have been driven fully open at highway speed. A folded stack can still whistle on the highway, loud enough that an owner of a BAKFlip-style tri-fold took the cover off for trips that needed it folded rather than listen to it.
• Soft tri-folds. Follow your maker's instructions to the letter. For the Tyger T3, Tyger's FAQ doesn't recommend highway driving with its tri-fold folded, and on regular roads says to keep the safety clamp secured to the side rails. Its warranty requires both safety straps secured whenever the cover is folded to the cab and says driving with it open at high speed voids that warranty.
• Roll-ups. RealTruck says the Sentry CT and the Revolver X4s roll to the cab, secure with their integrated straps and can be driven open. BAK's Revolver sheet says a cover driven open must be rolled to the cab and secured with both strap clamps, and the CT's warranty excludes driving with the cover partly open. Cinch the straps so the roll can't shift.
• Retractables. The slats live in the canister when it's open, so there's no stack to catch the wind. The Peragon Landmark folds its panels into a stack instead; Peragon says rubber isolates every panel, and a new one was quiet in city and highway driving, but an older one on a Ram 2500 banged around when folded.

Don't drive with the tailgate down and the cover closed. TruXedo customer service told a Sentry CT shopper not to, because the cover would flap around and come unvelcroed. If you're hauling something long, open the cover fully and secure it the way its instructions say.

What not to do

A few fixes for noise make things worse.

• Cranking the clamps. Tighter than the sheet doesn't mean quieter, and BAK's Revolver sheet warns that overtightening can warp the bed cap.
• Lubricating a squeaky retractable. RealTruck says lubricating the rails or sealed ball bearings voids the RetraxPRO XR warranty, and BAK's Revolver sheet warns that lubricants and solvents can damage its rubber hinges and seals. Clean the tracks with mild automotive soap and water, which is what RealTruck's warranty terms call for.
• Ignoring a flap. Tyger's warranty says an unsecured cover will flap and may damage the product and the vehicle, and lists wind whip damage among the conditions that void it. BAK's Revolver sheet warns that a partially rolled up or unsecured cover may detach in transit. A loose cover can come off. An older BAKFlip whose latch rivets had worked loose blew off the bed while towing, and a Revolver X4s came off its rails in the wind after 13 months.
• Silicone, glue or trimming. Sealant on a hinge or fold glues it shut, and a seal you trim can't be put back. Ask the maker before you cut anything and get the answer in writing; the warranty terms are theirs.
• Hunting the noise from the bed. Listen from the cab or walk around the truck. Never ride in the bed, and never close a cover over anyone.

When a quieter cover is the fix

Stop adjusting when the noise comes from the design: a panel with no latch, a stack that whistles every time you drive open, or a soft cover you can't keep tight. Here's how the covers we've reviewed compare on noise.

For a quiet bed we'd buy a hard roll-up, and the TruXedo Sentry CT is the one. A hard folder is fine if every panel latches, which is why we'd take the UnderCover Ultra Flex over a cover with an unlatched panel. Of the retractables, the RetraxPRO XR has the cleaner record, though no slatted cover is immune on bad roads.

Soft covers split owners. Some say soft roll-ups can't handle the wind and would only consider a metal roll-up; others have run a soft cover for five years without a flap. We side with the second group on one condition: a soft cover is quiet only for owners who keep it tight. If you won't check the tension every few weeks, buy a hard cover. A one-piece lid has nothing to flap, but it gives you the least bed access, and we haven't reviewed one.

Whatever you switch to, buy the listing for your exact truck, bed length and tailgate, set it square, and drive it on the highway the week it goes on.