You can spend thousands on alloy wheels and for some they are a status symbol in themselves. For most of us however, they can be a real pain to clean and maintain. As you may imagine, professional valeters and detailers have a vast array of products, equipment, and techniques at their disposal.
Most alloy wheels are painted and lacquered just like the paint work, be it with products that are better able to resist the temperature and abuse wheels tend to suffer. That said, some are diamond cut (though these are often also lacquered), some are hydro-dipped (though not from factory), and some are even made from carbon fibre.
It is possible to clean wheels while they are on the car, though this is made easier if the car is on a ramp and the wheels are able to rotate freely. However, detailers will remove the wheels entirely in many cases, particularly when applying sealants. When removing wheels it is worth checking the condition of the alloy and tyres – if they have buckled or there is a nail in the rubber it’s a safer way of finding out compared to a blow-out on the motorway. Equally when replacing the wheels, make sure you torque the bolts to the correct level, and check them after 50 miles to ensure they haven’t loosened. Many modern tyres, particularly asymmetric versions, have directional tread – so make sure you put them back on the car exactly as they came off. Some cars, particularly rear-wheel drive models, have different wheel widths and even diameters front and back – so again, make sure you pay attention when re-fitting them.
The key to cleaning wheels successfully is understanding the different types of contaminants that affect them, and then taking a methodical and disciplined approach to avoid missing areas. When the wheels remain on the car, it is worth moving the car forward by two foot halfway through so you can see areas that were previously out of sight.
Generally speaking, the first step is a detergent-based cleaning solution - leave it to dwell and then spray off. This will remove the loose dirt and allow you to see what remains. Normally you will be left with a combination of brake dust, which can be removed with a fallout remover, and tar deposits, which can be removed by a suitable solvent-based tar remover. Remember it is always better to hit it twice with correctly diluted products rather than once with overly strong products and risk damaging the lacquer.
Always remember to rinse thoroughly after cleaning and check the brakes!
Issue 1 of the PVD Pro Detailer magazine has two articles – one on wheel cleaning, the other on wheel sealing – both are worth having a look at. There are also plenty of products for wheels listed in various issues while there will be a future Megatest on fallout removers soon.