I keep mine at 40psi.

A few things, Hymer/Eriba realised they had dropped a clanger in 2007 in that the advised tyre pressures were to low. The 102 is also a high load rating for your 1200kg van. I carry a print out of a couple of the pages in the attached. It is the best starting point as it covers standard car,reinforced and light commercial tyres, all of which require different pressures for similar sizes.

Colin

Bob,
I'd forgotten that am running the same tyre and made the corrections you are trying to work out. You are correct in your thought process that 65psi is to high as you are not at 1700kg. Mine have been set at 3.3bar - 48psi from new and checked/set at the same each service. When running at close to max load I do raise them to 3.5 bar if I remember, which can show about 3.8 bar when hot. I have ran them like this for 7,000 miles and all is well. These figures tie in with the corrected tyre pressure chart issued by Hymer in 2007/8, as attached.

Colin

Always glad to help Bob. I've found that tyre pressures and noseweight are critical in allowing a good safe tow. If you get these correct you are off to a good start. Aim for the 48psi and about 60kg noseweight and then adjust as needed. I say 60kg as I've found in VAG car ownership since 2004 that towing I get best results about 55kg, but your A4 is a little heavier than what I have owned.

Colin

Not wishing to put a spoiler on it but please check that your tyres are up to putting 48 psi into them. Like everything else, there is a max tyre pressure rating on each tyre.(and don't forget that when hot the pressure increases by about 10 %)
Randa

Good point, Roger.

My tyres are clearly marked 'never exceed 40 psi' - which, obviously, is why I keep mine at 40 psi.