nylon timing belts -- stretch or snap?

["Cuadra" <cuadra@domain.elided>]

Just curious -- do nylon timing belts stretch over time or do they just tear
in half and break? 

A motorcycle chain, e.g.,  will stretch with age and mileage, and can
eventually break off, too.

Paul cuadra@domain.elided

a working stiff with no TV/VCR/cable  (but I have a 6 year-old Aiwa boombox)

164 LS 5-speed
Moto Guzzi Sport (shaft drive)

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