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Kia Rio front hub/ARP stud question

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  • Kia Rio front hub/ARP stud question

    Afternoon everyone. As I continue to plug away at my suspension build, I've run into a bit of a snag. I purchased a set of ARP 100-7719 Miata studs to run in my Rio hubs/Aspire rear brakes. In prepping to take my drums to a machine shop to have the holes drilled to the proper size to allow the studs to be pressed in, I decided I'd press out the stock Rio studs from the front hubs and install the ARP's while I was at it, however, the stock Rio studs have a bigger base than the ARP's, meaning the hole is now too big to install the new studs. Where did I go wrong? Is there any problem with having another set of holes drilled in the front hubs to allow installation of the new studs?

    Thanks for reading!
    1990 Flat black Festiva...Mostly stock...

  • #2
    I have not run into that problem on all the 2002-1/2 through 2005 Rio hubs I have done. It is OK to drill a new pattern, be exact. Ream final diameter .495 inch.
    what size are the holes now?
    Last edited by Dragonhealer; 01-24-2018, 07:45 PM.
    No car too fast !


    • #3
      There are different arp knurling sizes. The 100-7720s have a .579" knurl dia.
      The ones you got have a .507 knurl dia.
      ARP recommends a hole .005-.007" smaller than the knurl dia in steel, but going slightly smaller as Ryal suggested is probably fine. So I would probably measure your hole and buy a set of studs that are appropriate.
      Or I'm fairly sure you will be fine drilling another set of holes between the first set, if you already have the studs.

      the keeper of a wonderful lil car, Skeeter.

      Current cars:
      91L "Skeeter" 170k, Aspire brakes, G15, BP, Advancedynamics coil overs, etc. My first love.
      1990 Kawasaki Ninja 250 - my gas saver, 60+mpg - 40k
      2004 MotoGuzzi Breva - my "longer range" bike - 17k

      FOTY 2008 winner!


      • #4
        That sucks, figures I'd buy the wrong ones...

        Machine shop is going to drill out the hubs for me, taking the specs to them after work. Thanks guys!

        Sent from my iPhone using Tapatalk
        1990 Flat black Festiva...Mostly stock...