The RamBit will is the size of the street elbow, not the inserted flange. They do not make tools the size of the pipe's interior, just its o.d. so you can remove a pipe from a fitting. If it were a hub elbow with a spigot flange into it, the RamBit would work, because the spigot WOULD be "pipe size". You have to remove the flange by some other means, and it might be safer to call a plumber who MIGHT be able to do it without damaging the street elbow.