>>1692840my experience is that a chain will last 4000 km before it wears enough to start damaging the rear sprockets (according to a chain checking tool)
and a chain costs 1/3rd of a freewheel, so I figure three chains will last 12000 km, and by that point the freewheel likely has other problems
one of my bikes I kept using the same chain for 8000 km, it still worked with no skipping at all,
things were looking thin, I decided to get a new chain before the old one broke
But I found that the new chain would not work with the old sprockets, as the teeth had become a longer pitch than 12.7 mm
the rollers could not sit deeply enough into the valleys
chain rings take much longer to wear out
but I have found people do wear out Hyper drive C crank sets
for max durability I would recommend 8 speed chains, they are around 7.2 mm wide and available in modern metals
I have also observed that uni glide takes longer to wear out than hyper glide, but uni glide is mostly 7 speed
the last thing is more teeth touching the chain = lasts longer
take a typical bso 48x14
72x21 is the same gear ratio
65x19 is close
