Klein Attitude Comp MTB Frame | 17″ Med | 3.5 lbs ZR9000 | Sunburst Fade – MINT

Description

⭐ Condition Near Mint — a few scuffs – very minor

📏 Will this fit me?

Frame Size: Klein 17″ / Medium

The number to trust here is the effective top tube: at approximately 54cm, this frame sits squarely in medium territory by any modern sizing standard. Klein’s aggressive geometry — steep angles, short rear end, sloping top tube — means the seat tube was always going to be compact relative to reach.  Don’t size this frame by the seat tube number. Size it by the reach.

• Top Tube (effective): ~54cm Actual: 56cm c-c
• Seat Tube: 16″ center-to-top (Klein labeled 17″)
• Down Tube: 657mm center-to-center
• Chainstays: 420mm center-to-center
• Wheel Size: 26″
• Rear Dropout Spacing: 135mm

🏆 The Story Behind the Frame Klein Attitude Comp — Serial #T BI-1246 / 19H 0100 NTUI123706R — Sunburst Fire Fade

Gary Klein was an MIT-trained engineer who built his first aluminum frame as a student project in 1973. In a community south of Chehalis, Washington — a blue-collar logging town halfway between Portland and Seattle — Klein built his bike frame factory. His goal was to take the ordinary and make it extraordinary with the industry’s best materials and paint that cost upwards of $1,800 per gallon. The cherry on top? This frame was ridden before it was sold. The people who built these frames actually rode them. That’s a different kind of quality control.

• Compared to 6061, ZR9000 aluminum has yield strength about one-third higher and a fatigue life up to five times longer at the same loading.

🚴 The Ride The Attitude Comp has a reputation among veteran XC riders that hasn’t faded with time — stiff, responsive, and rewarding under hard efforts. The short chainstays and oversized tubing put pedaling power directly to the rear wheel with almost no flex loss. Riders who know how to set up a hardtail will find this frame pays back immediately. It’s not a comfort bike. It’s a performance bike that happens to look like a work of art.

🔧 What do I need to build this frame?

• Fork: 1-1/8″ threadless
• Headset: External 1-1/8″ threadless, 34mm cups
• Bottom Bracket: 73mm English (BSA) threaded
• Seatpost: 31.6mm
• Front Derailleur: 34.9mm band clamp, bottom pull
• Brakes: Cantilever or V-brake (rim brake only — no disc mounts)
• Rear spacing: 135mm — compatible with 8, 9, and 10-speed MTB drivetrains

🔧 Workshop Wisdom The internal cable routing through the top tube is a Klein signature — elegant when done right, fussy to set up. First set cables into shifters / brakes. Then run housing and barels to the internal guide holes. These have stops so housing wont slide through. Then route cable into the internal routing holes all the way to the rear side (exit side) – then slide housing internally and measure prior to cut.

📋 Other Frame Details

• Material: Klein ZR9000 proprietary aluminum alloy
• Made in USA — Chehalis, Washington / Waterloo, Wisconsin (Trek era, circa 2002–2003)
• Weight: 3.5 lbs (frame only)
• Serial: T BI-1246 / 19H 0100 NTUI123706R
• Paint: Sunburst fire fade — deep red / orange / yellow gradient, Durethane enamel finish
• Originally spec’d with XTR 9-speed

Is This Your Bike Thing? One of the finest American hardtail frames ever built — Klein’s fire fade Attitude Comp, ready for the build it deserves. Reach out before you buy and let’s make sure it’s the right fit.

Keywords: Klein, Attitude Comp, ZR9000, aluminum hardtail, 17″ medium, 26″, sunburst fade, fire fade, vintage MTB, retro mountain bike, USA made, Chehalis, internal cable routing, 135mm spacing, V-brake, cantilever, 73mm English BB, 31.6 seatpost, Trek Klein, XC hardtail