The city of Uden, Noord-Brabant is currently featuring the biggest mobile chair swing ride in the world. It stands at 80 metres and can go up to 70 kilometres an hour. Specification wise, it is identical to the Star Flyer at Tivoli Gardens in Copenhagen, although that swing ride is a fixed one.
The biggest fixed swing chair ride in the world can be found at Six Flags Over Texas in the United States, and its called Sky Screamer. It has a height of 121 metres and reaches speeds of 56 kilometers an hour, which makes sense given the sheer size of the ride (POV video).
(Link: ed.nl, Photo of a chair swing ride at Oktoberfest, Munich)