There is one thing which the best development programme, the most innovative production technology or a perfectly tuned test programme cannot affect, however: how customers treat their vehicles, and as a result their valuable light-alloy wheels. As always, how the wheels are treated has a significant influence on their value retention and also the safety of the vehicle.
Resistance to driving forces
It is a story which has featured in the media on an almost daily basis: after one of the harshest winters for many years, and due to a shortage of funds, the roads are now in a pitiful state of repair. Suddenly nasty pothole have appeared in roads which in the autumn were still for the most part relatively intact.
Potholes are easily overlooked and are then therefore driven over at too high a speed. This can result in a heavy impact, which in extreme cases can damage both the wheel and the tyre. After encountering such an incident, drivers should stop briefly to check their wheel (and tyre) for any damage. In the case of visible deformation, for example a dent in the wheel rim flange, a more detailed check should be carried out by the specialists at the nearest Mercedes-Benz service centre.
Damaged wheels must be replaced
A light-alloy wheel which has suffered significant damage must be changed, even if many independent workshops are able to offer an inexpensive repair -such a step should be avoided at all costs. Mercedes-Benz light-alloy wheels are able to maintain their high performance thanks to the use of so-called “warm-storable aluminium alloys”. If a wheel is subjected to mechanical or thermal loads through welding, bending, flexing or grinding, the metal microstructure is likely to change in the treated area. This can weaken the wheel at this specific spot, such that it is no longer able to achieve its original strength value at this point. In addition, Mercedes-Benz wheels treated in this way no longer comply with the general certification for the vehicle. When repairing damaged paint finishes, only paints which harden when cold may be used. High-temperature bake-on paint finishes can also adversely the metal microstructure.
Correct wheel bolt connection is also just as important for ensuring the long-term operational life of a wheel and as such the recommended Mercedes-Benz wheel tightening torques should therefore be observed. Wheel bolts which are fitted too loose or have been applied with brute force can damage a light-alloy wheel. When tightening the bolts, it is also worth noting that the wheel bolts should not be oiled or have grease applied to them. This could cause the initial stress to be higher than the recommended tightening torque, resulting in damage to both the wheel and the bolts.
A lasting shine for light-alloy wheels
In spring, following the intensive salting of the roads which takes place in winter, wheels should be washed thoroughly to ensure that all salt residues are removed. This is particularly important when cleaning winter wheels which are to be stored during the summer.
It is also advisable to gently and immediately remove any residues left on the paint finish. Natural chemical residues in particular, such as bird droppings or certain tree resins, should not be left on the wheels for long periods of time because, despite the increased resistance of the clear coat, they can cause damage over the long term. Regular paintwork care and protection with special waxes can increase the resistance of the paint and help to make the removal of residues easier. The care system from Mercedes-Benz is highly recommended since the individual cleaning, care and protection agents have been designed specifically for the paint system used on wheels. One important point to note: according to the latest research by the Mercedes-Benz paint development department, aggressive cleaning agents can attack the uppermost paint layers and damage the perfectly coordinated protection system. Rough, abrasive and harsh sponges should also be avoided when cleaning.Damage caused to the paint finish should always be treated so that the overall coordinated protection system can continue to be effective. If immediate repair with cold varnish is not possible, it is recommended that the damaged area is temporarily sealed – especially in winter. Scratches can be covered with regular adhesive tape or a touch-up stick until a specialist from one of the Mercedes-Benz support centres has examined the damage and arranged any necessary repair or replacement.
Observe the regulations relating to wheels
Light-alloy wheels from Mercedes-Benz are extremely durable. It is not for nothing that the test specifications for new wheels at Mercedes-Benz significantly exceed the statutory requirements. Their high performance is linked to specific conditions which must be complied with. As a result, the wheels should only be fitted with tyres of the relevant approved sizes. When driving with a heavy load, for example when going on holiday with a lot of luggage and towing a caravan or sports trailer, the tyre inflation pressure should be increased in accordance with the details indicated in the owner’s manual, and at the same time the permissible wheel loads should not be exceeded.
Source: Daimler AG