Who was the original bassist replaced by Duff McKagan in 1985?

The original bassist replaced by Duff McKagan in 1985 was Ole Beich.

Beich was part of Guns N' Roses' first lineup when the band formed in March 1985. That early configuration also included Axl Rose, Izzy Stradlin, Tracii Guns, and Rob Gardner. After only two rehearsals, Beich was replaced by McKagan, who had previously played in Seattle punk bands and soon became central to the band's classic rhythm section.

The change happened before Guns N' Roses' first public performance. Tracii Guns and Rob Gardner later left as well, leading to the arrivals of Slash and Steven Adler. The classic five-piece lineup—Rose, Stradlin, Slash, McKagan, and Adler—was in place by June 1985.

A common mix-up is Tommy Stinson, who replaced McKagan decades later, in 1998. Jeff Pilson and Mike Inez were never the bassist who took Beich's place in the original 1985 formation.