Ralph J. (R.J.) Herrera is a heavy metal drummer. He is best known for being the drummer of Suicidal Tendencies between the years of 1984 and 1991. After Suicidal Tendencies, he joined Uncle Slam, a crossover thrash band featuring ex-Suicidal members. While in Suicidal he used double bass drum kits, a feature often associated with metal music as opposed to the hardcore punk Suicidal was associated with when he joined. Herrera, along with Rocky George and Mike Clark, was largely responsible for the band's transition to thrash metal. He left in 1991 due to unspecified personal differences, but was thanked in the sleeve of the band's next album The Art of Rebellion for "8 outstanding years". Herrera has done several guest jams and in 2002 was seen playing with old band mate Rocky George and guitarist Anthony Gallo at the Kit Cat club in Hollywood on Sunset, where other drummers included Nick Menza of Megadeth.
He seemed to have had a very cheery and happy appearance and was frequently pictured smiling, which made him somewhat popular with Suicidal fans. He is not related to Fear Factory's drummer Raymond Herrera, despite the fact that they have the same last name and are both from southern California.
A Suicidal Tendencies fansite tracked him down for an interview in 2010, in which he revealed that he hadn't spoken to Mike Muir in 20 years.