Kia Rio front hub/ARP stud question

[Zman86]

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!

[Dragonhealer]

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?

[skeeters_keeper]

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.

[Zman86]

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!


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