THIS PACK CONTAINS 1 TYRE
The idler tyre is a small but crucial part of the C2N Datassette mechanism. If the idler tyre is worn or broken, the tape will not be pulled past the head at a constant rate (if at all) which results in very poor loading performance and "chewed up" tapes. This is an age related problem as the idler tyre rubber degrades naturally over time causing slippage (which isn't improved by changing the cassette unit drive belt), and eventually total breakage.
Early symptoms usually show up as visible "tape slipping" when loading games and the tape slows, then speeds up again.
Sometimes, small gaps are visible in the tyre, or the tyre falls off completely and you find it inside the C2N case (see photographs).
The idler tyres are very hard to find now and these are from a brand new trial batch we had specifically made. They have been tested extensively and work perfectly.