I'm thinking of buying a new car, and one of the options it has is diamond cut alloy wheels.

What's the difference between normal and diamond cut alloys?

  • 1
    This question seems fraught with opinion, as Martin alludes to ... not closing yet, but leaning that way. Commented Apr 1, 2019 at 23:15
  • I really should know better! revised my question
    – George
    Commented Apr 1, 2019 at 23:23
  • Sounds like marketing BS to me.
    – Moab
    Commented Apr 6, 2019 at 0:51

3 Answers 3


There's nothing "wrong" with them, except they cost more, the finish doesn't last long, and you can only refurbish the finish a couple of times.

But don't let that put you off, if you really want them.

More information here. The fact that that company doesn't guarantee diamond cut finish, even though they will do it, might also be relevant!


I'd never heard of this before. Apparently a diamond cut wheel is simply one that has been machined (no diamonds involved, as far as I can tell) to be shiny. They get clear-coated after the machining.

It removes a tiny bit of material (if done properly). Perhaps your friend is trying to save you the embarrassment of driving around with shiny wheels. Just kidding, I have no idea how polishing a wheel could harm it (assuming it was done properly).

It's your car, if you like them, do what you like!

  • I believe it is a diamond tipped cutting tool that is used.
    – HandyHowie
    Commented Apr 1, 2019 at 22:04
  • @HandyHowie - that may be true, but none of the vendors of diamond cutting equipment mention anything about diamond cutting tools. I think they are referring to the shine/reflection. I could be wrong, but it seems like if they were actually using diamond tools, they'd mention it specifically. "...a thin layer is cut from the alloy using a specialist CNC lathe." Wouldn't you think they'd mention diamond tools?
    – Tim Nevins
    Commented Apr 2, 2019 at 14:13
  • First place I looked - mikebrewermotors.com/blog/… - "Instead, we use a special machine with a diamond tip tool (and yes, there are actual diamonds in the cutting tool!) to remove a layer of metal from the wheel that is thinner than a sheet of aluminum foil."
    – HandyHowie
    Commented Apr 2, 2019 at 14:23
  • Well, that makes one!
    – Tim Nevins
    Commented Apr 3, 2019 at 13:08
  • Here is a second, if you need more evidence - austinconsultants.co.uk/project/diamond-cut-refinishing "The wheel is painted and then cut back using a special diamond coated cutting tip to expose the metal and provide a high-quality finish"
    – HandyHowie
    Commented Apr 3, 2019 at 13:24

It is only about appearance and diamond cut is in style this year. The aluminum cast wheels are coated ( usually black) then a diamond , or equal , cutting tool trims off the high areas giving a black and silver wheel. Diamond ( or exceptionally hard) cutting tools are used because cast aluminum typically contains about 10% silicon ; the aluminum and silicon combine to make some very hard intermetallic compound which will wear away most cutting tools quickly.

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