There's also Porto-Velo, starting in Portobello. Their main rides are on Sundays and are more "social" rides with a cafe stop and about 60 miles. Good for getting back for lunch. See http://porto-velo.com/ . Free to join.
There's also a few informal clubs, not clubs at all really, that organise themselves over the internet and meet up for weekly rides. I know of two, Pentland Velo who I believe start their rides from Craigdon Mountain Sports near Swanston and Dalmeny 801 who start from Dalmeny train station just out of South Queensferry. There may be others.