well i know AudiTT dont have a spare tyre and that they have a can of fizz.
so yes its true, the fizz thingy is not perm, its only a temporary which only last for certain miles, it just allows you to get to the closest garage for a new tyre.
Quite a few cars don't have spare tyres now, the tyre repair people love them, takes ages to get the goo out of the wheel before they can fit a new one, cost a lot more than a simple tyre change.
It's not just Audi, my last two Focus haven't had proper spare wheels, they have something like an oversize, a bright red bicycle wheel, that is supposed to get you to the nearest garage.
The spare can be totally bald. You can carry a cartwheel if you like.
It only becomes an offence when it is attached to the axle, and used on the road. Otherwise how could you carry a damaged wheel that you had removed from the car?
Mr ask was horrified when he found that he couldn't use a spare wheel with the Honda Accord, just the fizz stuff to tide you over. He has actually bought a (new)spare wheel and tyre for the car because he wants to be able to change the wheel. Men!
Gran when I bought my new car it didnt have a spare wheel just the fizz. A mate of mine who has his own garage advised me to get a spare as the fizz can make you change the whole wheel and not just the tyre apparently
We have a Citroen Grand Picasso which has no spare wheel to allow the fold-away seat to be stowed and still give a decent sized boot.
The answer? Ultraseal.
It's a one time application of stuff (technical, sorry) which is a fluid with small fibres in which seal holes on the contact surface of the tyre should you pick up a nail or similar.
We've had it in the car since new, now 2 1/2 years and had no problems with various nails etc. Just remove the foreign body and while you drive the hole is sealed.
Put Ultraseal in your search engine for a local stockist.