Mercedes Enthusiast Magazine Article

Getting our C43 AMG’s wheels refurbished has sometimes felt like a distant dream. But the desire came into sharp focus once we’d taken care of the bodywork early last year, a significant investment that was let down by a scruffy, untreated rim at each corner.

I say untreated, but the truth is we’ve had the 17-inch AMG monoblocks refurbished before and it was done very poorly. With that bad experience behind us, this time we were determined to do things properly, which is why we called on the services of Pristine Wheels based in Milton Keynes, a firm with a labour intensive and time proven process that delivers wheels which aren’t simply refurbished, they are effectively re-manufactured. Such is the scope of the process, it’s even possible to roll out wheel buckles, which our C43’s rims suffer from too.

So let’s cut to the chase, why are our rims so bad? “The wheels may not have been stripped properly during their previous refurbishment, which means the paint hasn’t bonded with the wheel’s surface,” answers Pristine’s Assistant Manager, Dan Kiff during our morning meeting. Looking closer at our wheels, Dan can see they’ve been diamond cut in the past and the lacquer has been rubbed down and simply painted over. Hmm.

"Mercedes’ wheels are really strong, but have a tendency to corrode over time,” says Dan. “Sometimes corrosion can lay dormant in the alloy and sometimes it can be on the surface; you can cut the latter away and the wheel looks like new underneath. These days manufacturers don’t seem to put enough paint and lacquer on their alloy wheels. With more applied, brake dust just sits on the surface for longer and is very easy to wipe off, rather than it eating into the wheel.”

Our C43’s wheels are finished in flat silver and, in the interests of maintaining originality, that’s what we’ve chosen for their restoration. Although we were tempted by the other silver finishes available including ‘Hyper’ (a deep and vibrant silver) and Anthracite (a dark, gun metal effect finish). We’ve also decided against returning to the original diamond cut edge, as this offers less protection than a painted edge. “If you damage a diamond cut and moisture gets into the metal, after six to nine months corrosion can get really bad,” warns Dan.

It’s at this point we are greeted by General Manager Linda Moulsdale who will be our guide around the workshops. The wheel restoration process begins where a car’s tyres are removed from the rims and stored, before the latter are checked for buckles and warping, and carefully and subtly stamped to help keep track of them (extra care is taken when stamping magnesium wheels as the metal is more brittle). Each set of wheels is assigned a job sheet, detailing the customer’s requests.

From there the wheels are moved to an area at the back of the facility, where they are chemically stripped and then shot-blasted. Industry rules now dictate an environmentally friendly, hot stripper must be used on the wheels, which takes around four hours to work, whereas the old, cold stripper did its job in an hour but was more corrosive. After all the paint has seeped away, it’s at this stage the technicians get a better idea of how bad – or good – the wheels really are and whether to proceed with the restoration.

Next, the now bare wheels are jet washed, before being put into a cylinder shaped blaster, which circulates fine shot-blast to remove the last paint residue from the wheel’s surface and make the surface clean for the new paint to stick to. This process usually lasts a few minutes per wheel.

From there, the wheels are transported in cages to the other end of the facility where they are examined for imperfections and rubbed down to a smooth finish, before being placed in another smaller blaster with even finer shot-blast, which gives a shiny finish you would not expect so early in the restoration.

Next we move into a room full of squat and heavy looking CNC lathes, each operated by one technician. These are the machines that give a wheel its diamond cut finish using a diamond tip, or if the customer doesn’t want that, the wheels’ edges are simply filed, removing any scruffy bits; the latter is what we’ve chosen for our C43’s monoblocks.

After the wheels have been turned, they are moved to a quieter wash area, where they are dipped in five separate baths with a more and more diluted metal treatment solution until finally, in the fifth bath, they are dipped in pure water. After being taken out of this bath, each wheel is hung on a hook and sprayed to remove any excess water, before it is carried into the oven which is degassed removing the last remnants of moisture from the wheel.

Emerging from the other side, now comes the primer, powder paint and lacquer to the customer’s specification. The room feels pretty warm and that helps the layers – applied by spray gun – to stick to the wheel’s surface. One wheel being worked on as we talk has a diamond cut finish, so it will just be lacquered. This effect may not be as durable as a fully painted wheel, but a diamond turned rim is as reflective as the back of a CD.

After a coat of lacquer, the wheels are put back in an oven to bake until the finish has fully hardened, the wheel inspected time and again to ensure the surface is smooth. For those customers who want a special colour for their rims (Pristine Wheels can create any colour you want), their wheels are taken to a separate wet paint area complete with its own oven. The wet paint gives a finish like apple skin, while powder paint, as we have selected for our C43’s wheels, is “like orange peel, but without the ripple effect”, explains Mrs Moulsdale.

The final stage for wheels being delivered back to customers by courier is the packing area – an important part of the process in its own right. Each wheel is packaged separately and protected by cardboard segments and laminate film. I notice one set of wheels is on its way back to Germany, so clearly Pristine’s reputation is well known.

We experienced first hand Pristine Wheels’ preoccupation with safety as, after the chemical paint strip and wash, the technicians discovered two of our wheels had been cut so much in the past, a pronounced lip had formed on the inner edge of the rims and their structural integrity was below what Pristine felt comfortable signing off. To the point that the company would not return them to us to guarantee they would be scrapped. After all, if something goes wrong on the road, it could be on their heads.

In an amazing stroke of luck, the company had two replacement AMG monoblocks to hand, and it was these and the two remaining originals that underwent the full, 14-stage, re-manufacturing process, which usually takes two to three days. As you can see, the results are magnificent and our C43 finally looks finished, on the outside at least. It was definitely smiles all round when we collected the keys and a feeling of relief too – this job has been a long time coming.

Thank you to Pristine Wheels for their help with this feature Tel 01908 282628 Web

Pristine Wheels is part of the Fred The Tread Tyres depot, located in Woburn Sands on the outskirts of Milton Keynes. Set up by David James in the early 1990s, the company dealt in tyres two decades prior but switched its attention to restoring wheels for cars and motorbikes after sensing a business opportunity. It now employs around 50 staff spread throughout several buildings on a two-acre site.

Private customers are varied, but others include dealers the likes of Mercedes-Benz, Lexus, Aston Martin and Ferrari etc, although the service is always professional and transparent no matter what wheels roll through the door. And if something isn’t right the company will inform the customer, as we found out with our C43’s wheels. Safety is paramount in this game, for Pristine Wheels at least.

We dropped off the C43 early doors, but the day was already in full swing for Pristine’s technicians. Time is money , so there’s no room for slack.

Pristine Wheels does not offer a mobile repair service, but they have agents around the country who offer a handy wheel exchange programme which keeps your car on the road.


Date: 04/11/2013