group rides. It is much easier to fit in a suitcase than comparable Bike Friday or Airnimal models, but less easy to pack than a Brompton. The only other hinge-free performance bicycle that is small enough to serve as a multi-mode commuter or that fits into an airline legal suitcase with minimal disassembly is the (unsuspended) Mezzo folding bike. A Birdy can fit into a standard airline-legal 29-inch suitcase, but this requires the pedals, wheels, and rear rack to be removed. Some Birdy owners have had difficulty fitting both the bike and the rear rack into a standard suitcase, and recommend the larger 31-inch format. When fitted with thin racing tires and removable pedals, the bike can fit in a suitcase with less disassembly. With a larger case (designed specifically for the Birdy), no disassembly is required. A standard slipcase must be used on some trains and buses. The suspension allows for a smooth ride on small wheels. The anti-dive suspension has minimal impact on pedalling efficiency due to its stiffness, while improving rolling resistance on rough surfaces. The suspension can be adjusted using different elastomers (small pieces of rubber that serve as suspension, but gas filled alternatives are available). The Birdy has no frame hinge, with both the front and the back points of contact serving as latches and shock absorbers. Thus, the downward force of the rider holds the bike together in such a way that the latches cannot fail while providing shock absorption. The bike has a sportier ride than the Brompton and has a wide range of gears. In sum it is a versatile bike, offering high performance, and sturdiness and luggage capacity for loaded long-distance touring using a variety of racks and panniers supplied by R&M and other manufacturers. Reviews, for example those by the reputable alternative bike magazine AtoB, point to the great speed and comfort of the Mark 2, but the folding is not always quick if you miss a step, and the tyres available for 18" rims were limited for some years. Tire selection is now adequate, and Kevlar-beaded tires, which can be folded for carriage in panniers, are available including the Schwalbe Marathon Racer. Disadvantages The main criticisms are: The Birdy is expensive, with some models costing as much as custom made bikes. Nonetheless, secondhand Birdys can be bought on eBay or from specialist listing like AtoB for as little as