OP asked what chain lubricant - various answers - old car oil / not old
car oil etc....
For what it's worth, and although generally practically-minded and with
a semi-technical background, I'm not an engineer - so it's just my two
bob's worth..
Given the horrible rusty chains quite a few leasure bikes end up with,
the main thing is oilding the chain, rather than not oiling it. A
bicycle chain doesn't exactly transmit a lot of power, even if you're
Lance Armstrong so it shouldn't really be critical. That said, I can
see that old car oil has got a lot of horrible sooty stuff, acids, bits
of metal etc in it, but would still be a lot better than nothing. I'd
guess that car oil would be too thick, or thicker than ideal shall we
say, as it's formulated to still be thick enough at high temperatures,
and has to stand much higher pressures in bearings and the like.
I'd have thought that something that said "bicycle chain oil" on the
tin should be pretty good - not just being facetious - but that one
might hope that at least some thought had gone into the contents. But
then, you're paying 5 quid a cupfull rather than a gallon. From my own
experience I like (but can't really justify) some road bike chain oil
in a little black bottle with added PTFE. Bike seems to run well, and
it's thin so doesn't atract [censored] quite so much. I previously used a
"mountain bike oil" from same company - but that was rather thick which
atracted too much muck - though presumably wouldn't get washed off so
easy. Thin and runny, but put on regularly enough not to dry out would
seem to do the trick.
