Hi
If you are looking for a space-saving bike with all the features of a full-size bike, you should seriously consider a Montague. They are full-size foldable bikes, rather than a commuter style folding bike with small wheels and skinny frame. They fold really easily and, unlike the commuter type folders, they look (and more importantly) feel, like a full-size bike when riding. This is principally because the frame has not been cut anywhere to have a hinge inserted for design convenience.
The Montague F.I.T. (Folding Integrated Technology) system is a really clever patented idea that employs a concentric seat-tube design that allows the bike to fold completely in half. Hinges can wear over time and give a folding bike all the ride qualities of a wet noodle! Although rare, there have been instances of hinged bikes folding whilst being ridden (gulp!) . This cannot happen with a Montague as the F.I.T. system has a sprung loaded quick-release mechanism on the frame. So even if the quick release is left undone (highly unlikely anyway), the bike couldn't fold because the spring keeps the skewer taught (phew!).
Because Montague bikes use all industry-standard components (serviceable at any bike shop), it means they have a full range of gears, decent brakes and can take a quick release seatpost rack and all other standard accessories. They are perfect for motor caravanners, boating, light aircraft, etc., or just for keeping in the boot of a car (park & ride!) or storing in a tight spot in your home or office.
UK site at:
www.montague-uk.com, US sites at:
www.montague.com and
www.militarybikes.com
If you are in the UK, I also know of a company that converts Montague bikes to electrically assisted models - and they still fold!
Good luck and stay away from the hinges!