The sidecars are a blast. It is interesting that even people who aren't interested in motorcycles or racing (my wife won't even ride!) will head out to watch the sidecars. She has already told me she might go watch the sidecars this year. I think it has to do with the passenger activity on the bike where in the regular races the rider is just leaning instead of hoping around. It is also very dangerous and the passenger is the one usually killed in accidents in these races.
The sidecars in the TT average 115 mph over a 37.75 mile course that has them at virtual stop at two hairpins. That is moving! However, they seem to suffer from more mechanical problems than the regular bikes.
