Ronnie Lane, bassist and co-founder of the Small Faces, the 1960s rock group that launched the careers of Rod Stewart and Ron Wood, died Wednesday in Trinidad, Colo., following a 20-year battle with multiple sclerosis. He was 51.Lane, a native of East London, founded the Small Faces in 1965. He co-wrote most of the band’s hits with lead singer and guitarist Steve Marriot, including “Itchycoo Park,” the only Faces recording to make the charts in the U.S. In the mid 1980s, Lane organized some of British rock’s biggest names in the A.R.M.S. concerts to benefit multiple sclerosis research. He is survived by his wife, Sue; and two sons. Private services are planned.