The Bench OP
THREAD STARTER · NANJING BENCH
A three-head deck came in last week with the classic symptom: reels spin, but take-up torque is uneven and the counter stutters. On most decks like this it is almost never the belt — it is the idler tire gone shiny.
Steps I follow: strip the transport, mark the flywheel position, pop the idler assembly off the shaft (no solvent, it is a push-fit), clean the shaft with isopropyl, and fit a fresh NOS-spec tire — not the generic 8 mm ones sold everywhere, they are 0.3 mm too thick and the clutch slips.
After fitting, I measure take-up torque across the whole cassette at 3 speeds. Spec is met on this unit at every point, and the wow figure dropped from 0.09% to 0.04%. Full bench report goes in the box.