AMuzi wrote:

Chain tensioners are handy on roadsters to
get the wheel centered what with full
mudguards, chain case, stirrup brake and so
on before tightening the axle nuts. They are
not necessary by any means

Great, that's what I thought!

and in fact the #1 problem with them is
riders setting chain tension too high which
causes excessive chain and bearing wear.

And bearing wear BEFORE chain wear, so one
cannot ride it until chain wear makes it right,
even if one is that destructive/lazy!
Many people put there chains too tight on
dropout bikes. But it happens easily enough!
OTOH as many people ride their bikes until the
chain is so loose it starts to hang and rattle
with everything else, and they still don't
bother (or know/care) as long as the bike
rides. I don't know. I'd like to know at least
something about everything that goes on around
me. But I suppose it is a good sign that not
everyone only thinks about bikes, computers,
gear, and so on...

A QR holds as tight or tighter than axle nuts
but either are adequate especially on single
speed where the gearing is not as low as
touring setups. Racing rules for track
prohibit QR. That and tradition are why real
track bikes use solid axles. (My own fixie is
QR, never posed any problem whatsoever))

Great!

--
underground experts united
http://user.it.uu.se/~embe8573