1990 Bridgestone MB-Zip
For a long time, Bridgestone mountain bikes had a reputation as having some of the nicest lugged frames, being made in Japan with Tange Prestige tubing but designed in the United States by Grant Pedersen and team. However, with the advent of even lighter Ritchey Logic tubing and the weight-savings of TIG-welded construction, Bridgestone created the "Zip" model to sit atop the numbered mountain bike (MB) product line in 1990. Whereas a TIG-welded Prestige frame might be just under 5 pounds, a Logic frame would save 3/4 of a pound and come in at just over 4 pounds. Because TIG-welding concentrates a higher heat into a smaller area compared to brazing, the thick butted end sections of the tubing could be made much shorter and the thin middle sections much longer. The MB-0 or -Zip wasn't just about saving weight with the frame, it also made extensive use of lightweight parts that were chosen carefully to achieve a total bike weight under 24 pounds. The derailleurs and minimalist thumb shifters were provided by Suntour, while Dia-Compe supplied the feathery 986 brakes and Advantage 5 levers with extra lightening holes. Although it was nothing new at the time, the Specialized crankset saved 100 grams over a Shimano Deore XT and provided a low Q-factor, or pedal-to-pedal width, as termed by Pedersen. Sealed cartridge bearing hubs were sourced from Mavic, and lightweight "directional" Ritchey parts adorned the controls department. Living up to the Zip name, the geometry was fast and maybe a little frightening. The head tube angle was nearly 72 degrees and on this large frame (21" center to top) the top tube is a generous 23 inches with a 135 mm stem. The ivory paint and matching saddled belied the fast handling. For the first production run in 1990, more than 800 frames were produced by the Taiwanese welder named Man-Chung Chiang, as claimed in magazine ads. Each frame got a number, this example being 387. Mountain Bike Action first shared a photo from Interbike in the January 1990 issue, and included it as one of 4 bikes in the Steel Fights Back article from June of 1990.
The Build
Year: 1990
S/N: M0A 37612 Frame: Bridgestone MB-Zip Fork: Ritchey Logic Stem: Ritchey Force Comp Headset: Ritchey Logic Comp Bottom Bracket: Specialized Sealed Bearing Handlebar: Ritchey Force Shifters: Suntour XC Pro Front Derailleur: Suntour XC Pro Rear Derailleur: Suntour XC Pro Long Cage Brake Levers: Dia-Compe Advantage 5-SL Front Brake: Dia-Compe 986 Rear Brake: Dia-Compe 986 Crankset: Specialized Touring Chainrings: Specialized 24-34-46 Pedals: Suntour Superbe Pro Track with Specialized Clips and Straps Hubs: Mavic Model 550 / 556 Cartridge Bearing Rims: Ritchey Vantage Comp Tires: Ritchey Megabite Overdrive Wheel QR: Mavic Seatpost: Ritchey Force Saddle: Selle Italia Turbo Grips: Ritchey True Grips Cogs: Suntour XC Pro Chain: Suntour XC Pro |
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