Hi,
Glad to be here.
We have a '21 Skoda Karoq Sportline with 19" wheels. Recommended tyre pressures are 2.4 bar all round.  
When we tow our caravan (90k'ish nose weight) by how much should I raise the tyre pressures....and would that be all 4 wheels?

Would you raise your tyre pressures when carrying passengers or luggage?

 

Look inside your fuel filler flap and you will see the laden tyre pressures which are for front and rear, if the only excess load is noseweight on the towbar then you should only consider the rear tyre inflation, for 90kg I would not do so.

Thank you for your reply to which the answer is Yes IF I was then towing.

I have always done this, as advised by those more knowledgeable than me, when towing but I've never had a 4WD before!

@MikeMann  Welcome.

Remember you do not have 4WD now, just part time AWD but you can still end up with tyres spinning towing or not towing if no traction with tyres and surface. 

Thanks again for the reply but sadly it's not my point.

 

It is Always recommended that the tyre pressures are raised from the normal when attaching and towing a caravan.   I'm not worried by tyre spin on soft ground as I would lower the pressures for this scenario.
This is my question, what extra pressure should I put in the tyres?

When towing before, with either a front or rear wheel drive car, the caravan clubs always recommended raising the pressures in the 'rear' tyres because of the extra loads created when towing a caravan.

 

Edited 14 July, 202414 Jul by MikeMann

@MikeMann Nail on head. It is always recommended.

 

Make your own commitment to what pressure you go with. 

You said 19" wheels, we can look at the tyre sizes, and recommended pressures, no idea what tyres are on your car though, i assume XL,s. 

Do not go to high, and if you think you need to reduce them do that. & have a good tyre pressure gauge. 

In nearly 40 years of towing caravans,loaded car trailers etc I have never raised the tyre pressures when towing, and never have I felt any need to. I've towed with everything from 1.3litre small hatches,  big engined luxury cars, part time 4wd, full time 4wd to 3.5 ton vans. Just hitched up, fix numberplate, check trailer lights and tyre pressures and off I go. The tow vehicles were and still are my own and the tyre ressures have always been checked regularly.