Re: Side car for a Mountain Bike?
Thanks for the sidecar links all in one place. Sometime I'll pull the canoe sidecar parts of my Firebird build thread and we can stick it in here. It uses the same frame and mounting setup as the kiddie trailer conversion. Lots of good information in the links.
Unless your girlfriend is child sized your are going to need a strong sidecar frame with substantial attachment to the bike... something like Fasteddy's sidecar (find it in the links) and the additional weight beyond a dog or a couple bags of groceries and you probably will want to go with fixed attachment points so the bike/sidecar is rigid. You would also need to ask yourself if the combined weight of you and your girlfriend are too much for the engine you're using. A lower geared rear sprocket or shift kit would make a difference. A motor powered tandem bike would be another answer to sharing the ride. Yet another would be to build a bike for her. That's the simplest yet and probably the least expensive in time and money.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...