2021 Polygon Syncline C3

Archived: 2021 Polygon Syncline C3 · Mountain · Published sizes: 27.5” SM, 27.5” MD, 29” MD, 29” LG, 29” XL

• 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: ACX XC PERFORMANCE · Fork: ROCKSHOX RECON SILVER RL, 120mm

• Inspect the frame in bright light, especially the head tube, bottom-bracket area, chainstays and clamped surfaces. Look for cracks, ripples, crushed sections or signs of impact.
• 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: ROCKSHOX RECON SILVER RL, 120mm · Rear shock: -

• 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.
• Inspect the shock shaft and seals, cycle the rear suspension through its travel and check for oil, air loss, binding or unusual top-out and bottom-out noises.
• Hold the rear brake and load the suspension from several directions. Check pivots, bearings and mounting hardware for knock, looseness or side play.
• Ask for dated fork, shock and pivot-service records. A clean exterior does not establish the condition of internal seals, oil, bushings or bearings.

Archived: Shifters: SHIMANO DEORE SL-M6100-R 12-SPEED TRIGGER · Rear derailleur: SHIMANO DEORE RD-M6100-SGS DIRECT ATTACH · Crankset: SHIMANO FC-MT510-1 32T 2-PIECE-CRANK · Bottom bracket: SHIMANO BB-MT500-PA · Cassette: 12 SPEED 11-51T · Chain: KMC NEW X-12

• 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: SHIMANO BR-MT201; Levers: SHIMANO BL-MT201; Rotors: SHIMANO SM-RT10 F:180mm R:160MM CENTERL LOCK

• Inspect pads and braking surfaces, check the complete cable or hose path, and confirm both controls feel consistent and return cleanly.
• 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: Wheels: ALLOY DOUBLE WALL · Rims: 584-30 / 622-30 32H FOR TYRE 584 / 622-54/76 TUBELESS READY · Hubs: F: SHIMANO HB-MT400-B 15x110mm 32H CENTER LOCK / R: SHIMANO FH-MT510-B 12x142mm 32H CENTER LOCK · Front tire: WTB TRAIL BOSS TIRE, 27.5x2.25 / 29x2.25 · Rear tire: WTB TRAIL BOSS TIRE, 27.5x2.25 / 29x2.25

• 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.
• Confirm whether the bike is actually set up tubeless, whether both tires hold pressure, and when sealant and rim tape were last serviced.

Archived: Headset: INTEGRATED W/ SEALED BEARING FOR TAPER HEAD TUBE, IS 42/28.6 | IS 52/40 · Handlebar: ENTITY XPERT, W: 740mm, BB: 31.8mm, R/D: 12mm, B: 9degree · Stem: INTEGRATED W/ SEALED BEARING FOR TAPER HEAD TUBE, IS 42/28.6 | IS 52/40 · Seatpost: ENTITY XPERT, 27.2x350mm · Saddle: ENTITY VOID SADDLE · Pedals: ALLOY CAGE PEDAL W/ REFLECTOR

• 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.