1998 GT Mach One (02)

Archived: 1998 GT Mach One (02) · BMX · Published sizes: Pro

• Confirm the frame markings and seller description match this archived model. Note every component that differs from the published build.
• Record the frame serial number. It should be legible, unaltered and consistent with the seller’s ownership history.
• Find the size marking on the bicycle and confirm the fit before judging the condition or price.

Archived: Frame: TIG-welded · Fork: GT · Chromoly, unicrown crown

• Check paint damage, vent holes and accessible internal surfaces for corrosion. Look for dents, bent tubes and cracking around welded or brazed joints.
• Stand behind and in front of the bicycle to look for obvious frame, fork or wheel misalignment. Ask directly about crashes, transport damage and repairs.
• Inspect the fork crown, blades, dropouts and visible steerer area. Check that it is straight, securely installed and free of cracks or impact damage.

Archived: Crankset: GT 1-piece chromoly, 43 teeth · Rear cogs: 1-speed, 16 teeth · Chain: 1/2 x 1/8"

• Check chain tension and chainline, rotate the drivetrain through a full revolution and confirm the rear axle or tensioning hardware cannot slip.
• Measure chain wear with a compatible gauge and inspect chainring, cassette or freewheel teeth. A new chain does not rule out wear in the remaining drivetrain.
• Turn the cranks slowly, feel for rough bearings and check for side-to-side play. Inspect crank arms, chainring bolts and pedal threads for looseness or damage.

Archived: Brakes: Tektro linear-pull rear brakes, Tektro levers

• Inspect pads, cables and housings, then examine both rim braking surfaces for concavity, cracking or heavy wear. Confirm each caliper returns and centers correctly.
• Before riding, test every installed brake separately at walking speed. Each should stop firmly and release cleanly without its control reaching the end of its usable travel.

Archived: Wheel size: 20" wheels · Rims: Weinmann Zac 4019 · Hubs: GT Mohawk · Front tire: Front: 20 x 2.125" GT AA Pro, Rear: 20 x 1.75" GT AA Pro

• Spin both wheels and watch for side-to-side and vertical movement. Check spoke tension, rim condition and hub play.
• Inspect both tire casings for cuts, cracking, plugs, bulges or exposed threads and confirm the installed sizes are safe for the rims and available frame and fork clearance.
• Remove and reinstall or closely inspect both wheel-retention systems. Axles or quick releases should tighten correctly with undamaged threads, hardware and dropouts.

Archived: Headset: 1 1/8" threadless Aheadset SE-1 · Handlebar: GT Low Pro · Stem: GT Piston · Seatpost: GT aluminum micro-adjust · Saddle: GT Drop Nose · Pedals: GT aluminum platforms

• Apply the front brake and rock the bike to check for headset play or notchiness. Inspect the stem, handlebar and clamp zones, then confirm every fastener and control is secure.
• Check that the seatpost moves for adjustment and that the saddle, post and clamp hold securely without cracks, severe corrosion or damaged hardware.

• Before riding, confirm both wheels are secure, tires are safe, both brakes function, and the headset, handlebar, stem, cranks and pedals have no looseness.
• Begin at low speed. Test steering, braking and shifting progressively, then load the drivetrain and suspension only after the basic safety checks pass.
• Listen and feel for repeated knocks, grinding, skipping, brake pulsation or movement at joints. Stop the test if the bicycle cannot be controlled safely.