Having the right tension on your roll-up tonneau cover is important to keep it secure and prevent sagging. Over time, the tension cables may loosen up and need adjusting. Adjusting the cables is usually a straightforward process, but the specific method can vary depending on the design of your particular tonneau cover. This article will walk through the general process and things to look out for when adjusting tonneau cover tension cables.

Why Do The Tension Cables Need Adjusting?

Tension cables are a key component of most roll-up tonneau covers. They run along the sides of the cover and connect to a tensioning mechanism, whether that’s a simple buckle, threaded knob, or tension block. The cables pull the cover tight as you roll it out over your truck bed. This prevents the vinyl cover from sagging and keeps your cargo secured underneath.

Over time, the cables can stretch out and loosen. This may happen gradually over many open/close cycles. Or sudden loosening can occur if you drive with the cover partially open, exposing the cables to whipping wind forces. In either case, loose tension cables mean the cover won’t sit flat and tight on your truck bed. It’s important to periodically check the cables and adjust as needed to maintain that snug fit.

How Can I Tell If The Cables Need Adjusting?

It’s easy to spot when your tonneau cover needs re-tensioning. Simply roll out the cover and look for these signs:

Sagging cover: If areas of the cover dip down or don’t sit flush with the bed rails, the cables need tightening.
Loose feel: Run your hands along the sides of the cover. It should feel taut across the surface. Any looseness likely indicates slack cables.
Excess cable: Inspect where the cables attach at the end of the cover. If you see a lot of slack in the cable rather than being pulled tight, adjustment is needed.
Cover shifts: Push on the cover from the sides or centre. If the cover shifts and lifts up easily, there’s not enough tension. Properly tightened cables will prevent excessive movement.

If you notice any of these issues, it’s time to tighten up those cables!

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What Do I Need To Adjust The Cables?

Before getting started, make sure you have the following:

Manufacturer’s instructions: Check the owner’s manual or installation instructions that came with your tonneau cover. Follow their guidance closely.
Basic hand tools: You may need a screwdriver, pliers, hex key, or wrenches. Have these ready.
Protective gear: Work gloves and eye protection are recommended when working under the cover.
Patience: Adjusting the cables takes some trial and error. Make small adjustments and test the results as you go.

Step-By-Step Guide To Adjusting The Cables

The specific process to tighten your cables will vary by design. But the general steps are similar:

1. Release The Cover

Start by releasing the cover from the fully closed position. This gives you access to the cables and tensioning mechanisms.

For a folding cover, undo the rear clamps.
On a retractable cover, disengage the tailgate bar.
With a hinged cover, release the side latches.

Once detached, you can roll or fold the cover open.

2. Locate The Tensioning Components

Find the cables, brackets, threaded knobs, or blocks that are used to apply tension. Common tensioning systems include:

Threaded knobs: Knobs mounted on the side rails that the cables attach to.
Tension blocks: Sliding blocks on the side rails that the cables run through.
Buckle straps: Straps with buckles that connect to the cables.

Refer to your owner’s manual if you’re unsure what system your cover uses.

3. Loosen The Cables

Before tightening the cables, you need to take the tension off.

For knobs, turn counter-clockwise to loosen.
Slide tension blocks forward, away from the tailgate.
Release buckle straps to create slack.

This gives you a baseline point to start tightening from.

4. Tighten The Cables

Now you can apply tension. Work in small increments, tightening the cables little by little:

Turn knobs clockwise about 1/4 turn at a time.
Push tension blocks back toward the tailgate in 1/2″ increments.
Pull buckle straps tighter one notch point at a time.

Go back and forth between the cables on both sides, keeping the tension balanced.

5. Test The Tension

Once you’ve made some initial adjustments, test the results:

Roll or close the cover to check for tightness and sagging.
Push down on the cover to see if it shifts easily.
Run your hands along the sides to feel for tautness.

6. Repeat As Needed

If there are still loose spots or slack in the cables, go back to Step 4 and tighten the cables a little more. Keep making gradual adjustments followed by tension tests until the cover is uniformly snug.

Be patient through this process and resist over-tightening. Overtightened cables can damage the cover or bed rails.

Tips For Adjusting Truck Bed Tonneau Covers

Consult manufacturer guidelines: Instructions vary, so always follow your specific tonneau cover maker’s tensioning recommendations closely.
Adjust both cables evenly: To prevent uneven tightness, alternate adjustments between the two cables.
Check tension regularly: Get in the habit of inspecting cable tightness so you can catch issues early.
Avoid over-tightening: Too much tension puts stress on cover components and the bed rails. Tighten cables gradually.
Close cover before driving: Never drive with the cover partially open, as wind force can damage loose cables.
Watch online tutorials: Viewing video walkthroughs for your model can clarify the adjustment process.
Seek expert help: For complicated or tricky tensioning systems, have a truck service shop adjust the cables properly.

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Why Proper Cable Tension Matters

It’s important to keep your tonneau cover cables adjusted to the right tension. Here’s why it matters:

Prevents cover damage: Loose cables put excess stress on the vinyl cover material which can tear over time.
Keeps cargo secure: Tight cables help keep the cover taut and in close contact with the bed, preventing cargo from shifting.
Deters thieves: A tight cover without sagging helps keep your truck bed and all it contains concealed and secure.
Looks better: Adjusted cables keep the cover in an even, smooth, unwrinkled state for improved aesthetics.
Improves performance: The right tension ensures the cover operates, rolls, and seals properly when opening and closing.
Reduces noise: Slack in the cover or cables enables the vinyl to flap around at highway speeds, creating noise.

Take a few minutes periodically to check and tweak your tonneau cover tension cables. Your cover and truck cargo will remain properly protected. With simple adjustments over time, you can add years of service life to your cover. Keep tuning those cables and you’ll keep your tonneau cover working and looking its best!