"www.GymRatZ.co.uk" wrote in message
...
On 07/04/2014 22:00, Dave Liquorice wrote:
On Mon, 07 Apr 2014 20:31:30 +0100, Bob H wrote:

I bought one of those pumps which you plug into the cigarette lighter
socket, and its great, with no effort required to pump up the tyres.

So did I when they first appeared on the market. Didn't take kindly
to the pumping up Discovery tyres, from 25 ish to 30 psi, exceeded
the duty cycle, over heated and died. 'twas only about a 2 cc
cylinder... It would have been alright with topping up ordinary sized
car tyres.

Same here. One from Costco. great for topping up a tyre, but when I took
all the van tyres up to 55 psi from 45 it managed 3 and just died on the
4th.
In fairness it does say something like maximum duty cycle 7 minutes then
cool for 20 minutes or thereabouts which obviously I ignored.

Now have a somewhat larger and fan cooled one more designed for the
truck market. B-)

I did consider rigging up a redundant diving cylinder to a tyre inflator
head/gauge but couldn't have kept it tucked away under passenger seat
like the tiddly costco inflator.

I guess you cant use one of these on modern vehicles:

http://www.mtfca.com/discus/messages/179374/194674.jpg

The good old spark plug inflator... remove a plug, screw the inflator end in
it's place, connect schrader valve to tyre, start engine and it chuggs away
on 3 cylinders (or 5, or 7 as they were a yank invention i believe)
inflating the tyre.

Apparently still used by the off road guys running simple engines in dune
buggies and sand rails, but a modern engine would go into limp home mode and
prolly not fire that cylinder again after the plug has been put back in,
whether it'd be injecting fuel whilst inflating i dunno, but if it did then
a fecked cat can be expected as well.