Ken yes but my question really (didn't make it clear) is why would they be so inflated

The engineers at Citroen and Michelin would have spent ages testing different pressure combos and decided that these were the best for everyday use by the majority of people.

This is what happend to my AK running down a straigh hill with 100 on the clock. Raid Co-drive decided to increase pressure to 40 PSI since the AK was (over)loaded with too much raid gear. I didn't feel the blow-out other than a big bang, the AK didn't pull to any side. It would be another story if the blow-out happened in a corner.

It is very simple. Too low tyre pressure and the tyre will wear quickly on the edges. Too high pressure and the middle will get worn quickly.

But bearing in mind Citroen specified 26 for the rear and only 20 for the front, when the front wheels carry more weight, surely it's not quite that simple?

My understanding is that, as well as what Viking has correctly stated, too high a pressure will lead to a lack of grip (presumably due to the decreased contact area, caused by a tyre which can not be deformed by the road surface). Certainly I've found that with the front tyres inflated to 26, there's more of a tendancy to understeer and to 'skitter' on poor road surfaces. With the 2CV's natural tendancy to understeer anyway, I suppose Citroen thought tyre life was of more importance than extra grip on the back. So, increase the pressures if you want, to gain tyre life, but you'll lose that lovely 'on rails' feeling.

This may be the case when the car's empty. Stick two adults on the back seat, or a load of firewood in the boot, or whatever, and it's a different story.
I must admit, I've never noticed the smallest difference in how the car drives with changes of five or so psi. They're not Formula 1 cars, and I suspect any difference anyone notices is largely psychological, because they know that there's a tyre pressure difference and they think they should feel something. I'm not talking about long term wear, or differences of ten or fifteen psi, but I don't believe the difference between, say, 20 and 26 psi is really noticeable in handling terms.

Why would anyone want to not use Citroens spec for tyre inflation for every day use?
Same as oil spec,why use anything other than specified?

because things move on? I no longer use Total "gold" never have, I use a semi synth and don't need to change the oil every 3000 miles either.

Can't argue with that!
But I do still reckon there is a slight difference to the handling depending on the pressures, I'm afraid!

Luke, I wouldn't say a 2CV understeers on here, you'll upset somebody