Could that be NBR, not NRR, for Nitrile Bonded Rubber. If so, then YAY! the bearing manufacturer has told you what the seals are made from but BOOO! they just bought generic seals rather than having them stamped with the actual bearing code - one seal can fit several different bearings.
Which hub?
Could that be NBR, not NRR, for Nitrile Bonded Rubber. If so, then YAY! the bearing manufacturer has told you what the seals are made from but BOOO! they just bought generic seals rather than having them stamped with the actual bearing code - one seal can fit several different bearings.