"Rod Speed" wrote in message
...
I suppose it you don't do much stop-start driving or having to hill-start
on steep hills, the clutch wear will be less than mine.

The difference appears to be how we drive, I dont ride the clutch, ever.

Depends what exactly "ride the clutch" means - I've never known precisely. I
presume it means letting the clutch slip any more than it has to in order to
do its job. Every time you set off from rest, the clutch will slip - that's
the whole purpose of a clutch, to cushion setting off at a minimum but
non-zero engine speed which, in the lowest gear, equates to a few mph, which
you don't want to present, in an instant, to the driving wheels. The amount
of slippage depends on the effective weight of the vehicle (ie mass times
sin(gradient angle)) and the engine speed. You try to minimise this by a)
keeping the engine revs as low as you can without stalling, b) letting the
clutch up as fast as possible without jerking the car so it spends a minimum
time slipping, and c) not applying much power until the clutch is fully
engaged.

Other gearchanges *theoretically* cause no wear if you manage to match the
engine speed to the road speed in the new gear. I'm probably not *too* bad
at getting it close, but I'm not perfect - my "good" to "cocked-up"
gearchange ratio is high but not 100% ;-) I certainly don't do what one
driver did who gave me a lift. She took her foot right off the accelerator
at each and every gear change, changed to the new gear and then either let
the clutch up on the idling engine (which caused a sudden retardation) or
else revved the engine to far too high a speed before letting the clutch up
(which caused a sudden jolt forwards). I dread to think what effect it was
having on her clutch. When she apologised and said "help!" after a
*particularly* bad jolt, I very tactfully suggested that it might be useful
if she tried at least to maintain the same engine revs, or else perhaps let
the engine note drop a little bit if she was changing up or let it rise
slightly if she was changing down. Admittedly it's not as easy as in a
modern car with a rev counter, but by no means impossible even if you've
only got the engine note to go by. Had she been a newly-qualified learner, I
could have understood it, though I'd have hoped her instructor might have
helped her perfect the black art of gearchanges, but she was older than me
and had been driving longer than I had. I earned a good few kudos points
when she said "show me" and I drove a little way, in a "strange car" without
any of the lurches that she thought were due to her car being clapped out.
It didn't help that she was fairly short and had small feet, so she had to
lift her heel off the floor every time she let the clutch pedal up, which
makes fine control a *lot* more difficult if you can't pivot on your heel.

Whenever I go to the supermarket and park in the car park, I hear the
tell-tale sound of a driver (usually elderly) who revs up to about 2000 rpm
and then lets the clutch just kiss the flywheel as he reverses out. The
slippage and the wear and heat don't bear thinking about. I'm spoiled in a
diesel car that the engine will pull when it's barely idling, so I can set
off with my foot off the throttle, just giving the car a little nudge and
then disengaging (fully!) as I let the car roll in or out of the parking
space, without any need for a racing engine. It only requires you to let the
clutch in slightly further than you intended when you're in first gear at
2000 rpm, and the car will lurch into the car or brick wall ahead.