Please watch this video on how to torque your wheelnusts.

1. Why Wheel Nuts Can Loosen on a New Van

When your new caravan first hits the road, or anytime you remove and refit a wheel, several things are happening at once:

• The wheel studs, nuts and wheels are bedding in under real towing load.
• The hub and wheel warm up and cool down repeatedly as you drive and brake.
• Small amounts of paint, coating or surface irregularities between the wheel and hub can compress.

This natural settling can cause a small reduction in clamping force on the wheel. If not checked and corrected early, this can eventually allow wheel nuts to work slightly loose.

2. What Can Happen if Wheel Nuts Are Not Rechecked

If wheel nuts become loose and stay loose:

• The wheel can begin to move slightly on the studs.
• This movement places extra stress on the studs and can cause:
  • Elongated or damaged wheel holes.
  • Studs to shear off in extreme cases.
  • In severe cases, the wheel can work its way off the hub.

Regular checks, especially in the early stages, greatly reduce this risk.

3. The Role of Wheel Nut Indicators (Red Arrows)

Many Mars caravans use wheel nut indicators – often the distinctive red arrows fitted over the nuts.

• When fitted, the arrows are normally aligned in a pattern at correct torque.
• If a wheel nut moves, its arrow will move with it, breaking the pattern.
• A quick glance can show whether any nuts have rotated since the last check.

Tip: Take a photo of your indicators at handover or after a professional torque check. You can later compare this to see if anything has shifted.

4. When to Recheck Wheel Nuts

We recommend wheel nuts be checked after:

• The first 50km of towing.
• Again by around 500km.
• Any time a wheel has been removed and refitted (e.g. tyre change or brake work).

Wheel nuts should also be checked as part of your regular servicing and before major trips.

5. Who Should Check Wheel Nut Torque?

Wheel nut torque should be checked with a calibrated torque wrench set to the correct specification for your wheel and stud size.

• Many owners choose to have this done by a:
  • Tyre shop.
  • Professional service centre.
  • Qualified mechanic.
• If you are experienced and have the correct tools, you may choose to do this yourself, following the manufacturer’s torque settings. Mars recommends 135nM

Important: Impact guns and incorrect tools can over-tighten or unevenly load studs. Always use proper torque procedures.

6. Simple Visual Check Before Every Trip

Even between formal torque checks, a quick visual inspection is valuable:

• Walk around the van before towing.
• Look at each wheel nut indicator (if fitted) and make sure the arrows still line up.
• Check for:
  • Missing nuts.
  • Cracks or damage around the studs.
  • Fresh metal dust or shavings around the wheel holes.

If anything looks unusual, have the wheel checked before continuing long-distance travel.

7. What to Do If You Suspect a Loose Wheel

If you feel vibration, hear unusual noises near the wheels, or suspect a problem:

• Slow down and pull over in a safe location away from traffic.
• Visually inspect each wheel and nut indicator.
• If you see obvious movement or missing nuts, do not continue towing until the issue is rectified.
• Call roadside assistance, a tow service, or a qualified repairer if necessary.

8. How This Fits Into Your Overall Maintenance

Rechecking wheel nuts is part of normal caravan maintenance and should be combined with:

• Regular tyre pressure and tread checks.
• Scheduled brake and bearing services by a qualified workshop.
• Visual checks of suspension and chassis components, especially after rough roads.

Summary

Rechecking wheel nuts after the first 50km is a simple but essential safety step for your Mars caravan. Thermal cycles, bedding-in and normal use can all cause small changes in clamping force. By performing early and regular wheel nut checks, you:

• Reduce the risk of wheel and stud damage.
• Increase safety for you and other road users.
• Look after one of the most critical parts of your caravan: the running gear.

If you have any concerns about your wheels, studs or indicators, contact Mars Campers support or your preferred service centre for advice.