"Rod Speed" wrote in message
...
So far in 40 years driving, I've never had a puncture while I've been
driving (apart from the blow-out when the tyre scraped against the edge
of the tarmac when I was forced off the road by an oncoming tractor) -
all my punctures have been of the sort where the car is fine when I park,
and then the tyre is flat when I come to drive away

I forgot when I said that about the incident with the drunken old man on a
bicycle who crashed into my dead wheel just after I'd taken it off to change
the tyre (see my posting of 18:44 today for that story).

Most of mine have showed up when driving. With one I could hear the
ticking
of the screw in the tread as I went around the corner and didn't bother to
do
anything about it because it was on the garage sale run. It did eventually
end
up visibly well down so I used the real spare. Another time, also on a
garage
sale run, someone pointed it out to me. The Getz doesn't give much
indication
of a flat tyre handling wise. Another on another garage sale run, forget
how
I became aware of that one.

When my dead wheel was run into by the drunk on the bike, I was driving my
mum's Renault 6 with very soft rolling suspension, like many French cars of
the 1970s and 80s. I had a lucky escape because I was probably driving a bit
faster round bends than I should have been (the dreaded "I've passed my test
about a year ago, I'm pretty good at driving now" arrogance - *not*
something I'm proud of) and if the car had gone out of control due to the
tyre overheating and coming off, I'd have probably crashed. As it is, I
didn't feel any difference in handling beforehand. The only things that made
me suspect that something was wrong were the noise of the rim on the road as
it had cut through the tread, and the smell of very hot rubber. It was scary
to think that I had no other sensation of the car pulling to one side or
rolling more on right hand than left hand bends. Fortunately the rim of the
wheel was not dented and could be re-used once a new tyre was put on it.

Nowadays you get "tyre deflation" warnings if a sparrow farts in the wrong
direction, so a tyre would never get that flat without you knowing. Our
Honda's warning system is very sensitive and gives a lot of false warnings.
After we had a genuine slow puncture, we had to get one tyre changed, so
there was a brand new tyre and one that had done maybe 10,000 miles on the
same axle. It took several weeks of driving, cancelling the warning whenever
it sounded (and initially, checking that the pressure really wasn't low)
before it stopped alerting us to a problem. I presume it didn't like the
slightly different diameters of the tyres of different ages. Does a larger
(newer) tyre tend to wear down slightly quicker than an older one on the
same axle? Could it be that after a few weeks' driving the difference in
diameters was less pronounced (if the new one had worn down to the same
level as the older one)? Does the relative wear of different ages of tyre
depend on a) whether its steered wheels or the back ones, b) whether the
axle is driven through a differential or totally independent wheels? In our
case, it was the rear wheels on a Honda CR-V 4WD, so the rear wheels *are*
driven, even if normally most of the power goes through the front axle
unless that loses traction.