Richie--Be not concerned either way. After all, these are car tires and designed to take abuse that you will never subject it to. I've run both RF and NRF. Currently, I'm running a Falken NRF and it grips like no MC tire I've ever seen. Only thing is you will run slightly lower air pressure in the RF than the NRF. Also, the RF tires are considerably heavier than the NRF.