On 11 Sep 2008 19:27:43 GMT, Adrian wrote:

The key is _totally_ flat, rather than just soft.

Agreed no tyre will survive long if internal surafces are being forced
into contact even just briefly on bumps. That I would call "flat". Soft is
when there is still pressure in the tyre but it's not enough and the shape
is visibly different and the handling noticeably altered. This is with
normal tyres mind not a thick rubber band...

If a tyre picks up a puncture and goes flat when running the chances are
it will be killed but a slow leak where you loose just a couple of
psi/week should be picked up by visual observation/change in handling(*)
or if those don't occur 'cause rubber bands are fitted rather than proper
tyres you'll have to resort to actual pressure checks.

(*) Trouble is modern cars are very reliable, just feed them fuel and
drive. Take them to the garage to be serviced occasionally and get the MOT
if it's old enough to require one. Many drivers simply don't notice via
the handling or bother to look for a soft tyre. To me a normal profile
tyre that is 5 to 10psi down is very obvious.

--
Cheers
Dave.