I've briefly peeked at the Oval racing websites(Rc4Less.com,Ovalstuff.com, LefthanderRc), and also TeamIRSRC and also TeamCRC......some of the options are teflon coated pivot balls , the standard # 8417 ones (plastic Associated parts) and the Bronze pinch-proof ones from CRC.

I've stuck with the standard issue # 8417 pivot balls. Good luck with your choice.