Introduction to Chrome Plated Wheels: Some technical questions answered

A. Hi Patrick.

It's always nickel plating followed by chrome plating. Chrome plating does not impart reflectivity and shine, the nickel does that. The chrome adds a slightly bluish cast, as opposed to the slightly yellowish cast of nickel; it prevents the nickel from tarnishing, and it contributes symbiotically to the corrosion resistance. There are usually pretreatments before the nickel plating, including zincating and either copper plating or electroless nickel plating.

The nickel plating is not porous and will not allow absorption of water.

Plating, done properly, does not significantly reduce fatigue stress.

Nickel-chrome plating is a barrier-layer type of plating, it does nor protect the substrate if it gets scratched.

It costs about as much to plate wheels as to buy a new set. That is because the original wheels were plated in large batches involving little labor per wheel. When four or less wheels are done at a time, it takes a great deal of manual labor per wheel as the process involves many many cleaning, polishing, and plating steps and many of these steps have to be carefully tailored to the exact shape of the wheel.

Good luck.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

P.S.: We have an "Introduction to Chrome Plating" that you may find interesting.

Q. Thanks for the great reply, As a follow up question, knowing that the chrome-plated wheels are pretty easy to clean, what kind of life expectancy do they have? Can they corrode?

Also, if the Nickel is applied first and the Chrome is layered on top, how can the shine of the nickel show through the chrome.

Thanks Again,

Patrick

A. Let's go off-track and talk bumpers first: An OEM quality nickel-chrome plated bumper lasts about as long as the painted body parts of the car or truck, sometimes a little longer, sometimes a little less. So, nickel-chrome plating is a very permanent finish that can last decades. If you had steel 'chrome reverse wheels', that might be the end of the story.

But the majority of fancy wheels today are cast aluminum alloy. This is very difficult to plate, both because the casting alloy is low quality aluminum, and because aluminum is inherently difficult to plate reliably for electrochemical reasons. So the odds are good that the bonding of the plating to the casting is poor in at least a spot or two, which will become apparent in use over a few years, revealing itself as pitting or peeling. If I were a consumer, I would not buy chrome wheels without a true replacement guarantee, and if I were the seller I might not offer one :-(

Plus, is it really possible to keep from scraping a curb day after day, year after year? The aluminum is very soft and will gouge, breaking the plating, and even if the damage is slight, the aluminum will start to corrode.

Regarding your second question, the nickel is self leveling and highly reflective. The nickel plating imparts "specularity". The chrome reduces tarnishing of the nickel and is a bluer color, but it follows the smooth mirrored surface imparted by the nickel plating.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

A. Hi Lauren, and thanks for the kind words. There is no accounting for taste, so any suggestion can raise the possibility that you simply will not like it. The most durable wheels are probably painted steel wheels (like on Cherokees, not Grand Cherokees). Second most durable is probably chrome plated steel wheels (pretty much out of fashion). Third may be plain aluminum wheels with a clearcoat (common on Grand Cherokees). Most troublesome is chrome plated aluminum.

The problems with chrome plated aluminum wheels are many. Even high quality aluminum is very difficult to electroplate because aluminum is an extremely active metal that instantly forms an oxide skin, and you can't plate oxides. So the first step is always a zincate replacement process, which usually lacks the adhesion of electroplating. You'll frequently see the plating just peel off of aluminum wheels; you very rarely see plating peel off of steel. Although this peeling is a manufacturing defect, the manufacturer will often try to blame it on the customer. Also, the wheels are pressure cast, not machined; and because they are castings they have tramp ingredients in them like silicon, making the plating even more unreliable.

Look at the warranty. Few manufacturers will guarantee them more than a year, and even then they are not guaranteed against road salt. Would you buy a car that had only a 1-year guarantee and an exclusion if you drove in the snow? It's ludicrous. But I doubt you'll find a long term all inclusive guarantee on chrome plated aluminum wheels because it's just too difficult to plate them right.

Finally, corrosion forces are working against you. As noted, aluminum is a very active metal. Put noble metals like nickel and chrome on it and then allow the tiniest perforation in the coating, and you have a powerful corrosion battery where galvanic forces will cause the aluminum to corrode quickly.

Chrome plated aluminum wheels are beautiful like flowers ... and about as delicate.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

A. It sounds like a good plan, Jim.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

A. I believe it would be possible to blast the chrome and nickel off of the aluminum wheels without damaging them in theory, but they are often so intricate that the job could be tedious and time consuming. So I believe chemical stripping is more practical. But that's just book knowledge -- I haven't actually done it or been involved in doing it.

Still, remember that the wheels are pressure castings, not billet aluminum. Because of this and the unavoidable silicon and other tramp ingredients, you'll never get them to polish up and shine like pure aluminum. Sorry.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

A. I think you should replace all four or all five wheels. This doesn't sound like an aesthetic issue to me; it sounds life-threatening in the event that the corrosion proceeds differently on another wheel, or if you hit road debris at high speed resulting in an instantaneous blowout through the rim.

I would suggest that you write to the corporation and request replacement wheels, and if there is no response then report it it to the NTSB and Consumer Reports [link is to product info at Amazon]. If they feel there is an actual life hazard, they will know what to do. Recalls help make corporations more responsive to consumer complaints about safety issues.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

A. Hi. If the rims are plated on their face and not elsewhere, Pat, you have dissimilar metals exposed and will have an increased corrosion rate for the aluminum.

Sorry, but we can't discuss prices on this site, you would need to get multiple quotes to decide.

Good luck.

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey