The mountain bikes of the late 1980s were not prepared for what the 1990s would bring to the American framebuilding scene, which was on the precipice of the aluminum revolution. Aluminum bikes were lighter and featured oversized tubing diameters, making a buff canvas for some wild paint jobs. This 1990 Klein Attitude is perhaps one of the most iconic bikes, donning the “Team USA” or “Dolomite” colors; green, white, and magenta—all sprayed on Klein’s thicc “Aluminum Power Tubing.”

While I was in Los Angeles, camping out at The Cub House, Sean got this bike all polished up for a quick shoot, so let’s check it out below!

Mike Wilk has already dished out the history of Gary Klein, the truly innovative framebuilder behind this bike and you should really check out his story on our Adroit feature if you’re interested in his background. In short, Klein was a vanguard of the era, and his career as a bicycle designer started as part of an engineering project at MIT in 1975.

This bike sports a serial number of BAT2D4, meaning it was built in 1990 as the 724th Klein to leave the shop. Significantly, it’s an early Attitude, which was Klein’s top-of-the-line mountain bike. The Attitude marked a sea change for rigid mountain bikes at the time, with a big, fat aluminum fork, and Klein’s Durethane paint that commanded the viewer’s attention.

Also released in 1990 and found on this build is the Mission Control, a T6 heat-treated aluminum bar/stem integrated cockpit and an oversized headset, sporting a diameter of twice the size of a standard 1″ steerer. To top it off, the Attitude features internal routing.

Sean‘s build, as he bought the bike, came specced with the standard Shimano Deore XT M730/732 componentry and a Dia-Compe 986 rear canti brake that was a bit narrower than the comparable Shimano model for leg clearance. The white perforated Flite saddle is the proverbial icing on this Dolomite cake. What’s most impressive is this particular build weighs in the low 20-pound range. Dang!

Build Spec:

Year: c. 1990
Frame: #BAT2D4
Fork: #5A31B
Bar/Stem: Mission Control
Headset: Klein 25 Oversized
Shifters: Shimano Deore XT (ST-M091)
Front Derailleur: Shimano Deore XT
Rear Derailleur: Shimano Deore XT
Brake Levers: Shimano Deore XT
Front Brake: Shimano Deore XT
Rear Brake: Dia-Compe 986
Cranks: Shimano Deore XT
Hubs: Shimano Deore XT
Rims: Campagnolo Mirox
Seatpost: Shimano Deore XT
Saddle: Flite