2010 Trek 3900 Disc

Archived: 2010 Trek 3900 Disc · Mountain bike, front suspension · Published sizes: 13", 16", 18", 19.5", 21", 22.5"

• 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: SR Suntour SF9 XCT V2, 100mm travel · Single crown

• Look for dents or shape changes and inspect the edges of welds around the head tube, bottom bracket, seat cluster and suspension mounts for hairline cracks.
• 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.

Archived: Fork: SR Suntour SF9 XCT V2, 100mm travel

• Inspect the fork stanchions for scratches or coating wear, look for oil or dirt rings at the seals, and cycle the fork through its travel while checking for binding or bushing play.
• Ask for dated fork-service records. A clean exterior does not establish the condition of internal seals, oil or bushings.

Archived: Group: Mountain Mix · Shifters: Shimano EF-50 · Front derailleur: Shimano C051 · Rear derailleur: Shimano M-360 · Crankset: Shimano M191, 42/34/24 teeth · Cassette: SRAM PG-830 · Rear cogs: 8-speed, 11 - 32 teeth

• Shift through every available gear under light load. Hesitation, skipping or inconsistent indexing can reflect wear, damage, poor adjustment or mismatched replacement parts.
• 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: ProMax Mechanical Disc brakes, Shimano EF-50 levers

• Check both cables and housings for corrosion, fraying or drag. Confirm each caliper releases cleanly, then inspect pad thickness, rotor wear and rotor alignment.
• 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: 26" wheels · Rims: Bontrager 550 · Hubs: Front: Formula Alloy DC20, Rear: Shimano FH-M475 disc · Front tire: 26 x 2.00" Bontrager LT-3

• 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 VP-A68-TK · Handlebar: Bontrager Approved Riser · Stem: Bontrager Approved · Seatpost: Bontrager SSR, 31.6mm diameter · Saddle: Bontrager SSR · Pedals: Wellgo Nylon Platform

• 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.