Short answer: Installation depends on the type of roof rails on your vehicle. If you can slide your hand under the rail (raised roof rails), the roof bars are secured with brackets that grip the rail. If the rail sits flush against the roof or the vehicle has factory mounting points, the bars are attached at those points. In either case, install them using the guide and video supplied with the product; the tightening sequence and the check after the first 50 km are the two most critical steps.
Before installation: which series are you using?
Correct installation starts with the right product. Look at your vehicle's roof:
- If you can slide your hand under the rail — there is a gap between the rail and the roof. On these vehicles, the TRX1 the corresponding series is used; the brackets clamp around the rail from underneath.
- If you cannot slide your hand underneath — the rail sits flush against the roof. On these vehicles, TRX2 the corresponding series is used; the connection is made to the vehicle's own mounting points or to the flush rail.
- If the vehicle has no roof rails — neither of these two series is suitable. Roof bars require rails or factory mounting points to attach to.
Compatibility on the product pages is determined by vehicle make, model, and year range; once you select your vehicle, the suitable series will appear.
Installation steps
- Open the box and count the parts. The box contains two crossbars, four bracket sets, lock cylinders, and an installation guide. Do not begin installation if any parts are missing.
- Clean the roof and rails. Dust and grit on the bracket mounting surface can scratch the paint during tightening and prevent the connection from seating properly.
- Identify the front and rear bars. The bars are usually directional; check the markings in the guide to confirm which one goes at the front. Fitting a bar backwards disrupts its aerodynamic profile and increases wind noise.
- Position the brackets loosely. Fit all four brackets, but do not fully tighten any of them. Adjust the position first, then tighten.
- Adjust the bar spacing and symmetry. The distance between the two bars must fall within the range specified in the guide; also make sure each bar extends equally on the vehicle's left and right sides. Roof bars shifted to one side carry the load unevenly.
- Tighten in alternating order. Tighten the brackets crosswise, not one after another (front left → rear right → front right → rear left). This prevents the bar from being pulled to one side and distributes pressure evenly.
- Fit and test the locks. Insert the lock cylinders and use the key to lock and unlock them to confirm they work. Keep the keys at home, not in the vehicle.
- Check by hand. After installation, hold the bar with both hands and push it forwards and backwards, then up and down. It should not move in any direction.
Should you install them yourself or have them professionally installed?
Thunder Carrier roof bars are designed to be installed using the installation guide and video included in the box without requiring a specialist ; the tool supplied with the product is usually all you need. Even so, if the installation uses the vehicle's mounting points or this is your first time installing roof bars, having a specialist do the work adds an extra layer of safety. The choice is yours; whichever option you choose, do not skip the checks below.
The most common installation mistakes
- Overtightening. "The tighter I make it, the more secure it is" is not true. Overtightening deforms the bracket and roof rail and can start cracks in plastic components. If the guide specifies a torque value, follow it; if it does not, tighten until secure and free of movement, without forcing it.
- Tightening one side at a time. Fully tightening one bracket before moving to the next pulls the bar out of position. Position all brackets loosely first, then tighten them in a crosswise sequence.
- Fitting the bars backwards. Fitting an aerodynamic-profile bar backwards noticeably increases wind noise.
- Skipping the first check. Connections settle after the vehicle has been driven. Stop after the first 50 km and recheck all fasteners — this one step prevents most post-installation problems.
- Forgetting periodic checks. During extended use, check the connections once a month; before a long trip, check them every time.
If there is wind noise after installation
If you hear whistling above a certain speed with the roof bars fitted, the cause is usually the installation. Check the following in order: are the bars fitted backwards, is the spacing set to the value in the guide, are the brackets fully seated, and are the end caps fitted? If these are correct, any remaining whistling comes from the exposed profile section; removing the roof bars when you are not carrying a load is the most effective solution. Thunder Carrier roof bars are designed to be easily removed and stored in their own box.
Frequently Asked Questions
How do you install roof bars on a vehicle?
First position the brackets loosely at all four corners, adjust the bar spacing and left-to-right symmetry, then tighten the brackets in a crosswise sequence (front left → rear right → front right → rear left). Fit and test the locks, then push the bars by hand to confirm they do not move. Recheck all fasteners after the first 50 km.
Can I install the roof bars myself?
Yes. Thunder Carrier roof bars are designed to be installed without a specialist, using the installation guide and video included with the product. If this is your first installation or the setup attaches to the vehicle's mounting points, you may prefer to have a specialist do the work.
How tight should I make the brackets?
If the guide specifies a torque value, follow it. If it does not, tighten the connection until it is secure and free of movement, without forcing it. Overtightening can deform the bracket and roof rail and cause cracks in plastic components. Always tighten in a crosswise sequence.
When should I check the installation after fitting it?
Carry out the first check within the first 50 km after installation, because the connections settle once the vehicle is driven. After that, check the connections once a month during extended use and every time before a long trip.
Do I need any special tools for installation?
Usually not. The tool included with the product is sufficient for most installations. A cloth for cleaning the surface and a tape measure for checking the bar spacing will also make the job easier.
There is wind noise after fitting the roof bars. Is that normal?
Noticeable whistling is usually caused by installation: bars fitted backwards, spacing that differs from the guide, brackets that are not fully seated, or missing end caps. Correcting these will noticeably reduce the noise. Removing the roof bars when you are not carrying a load reduces both noise and fuel consumption.
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