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Do you run the factory tyre pressures in your Type 4s if you have non-factory tyre sizes?

The sticker in glove box states 19psi for the front and 30 for the rears. Haynes states 20-23psi for the front and I'm sure I read on here somewhere someone ran something else on the fronts.

I have 185/65R15 tyres fitted all round on 6 inch rims. What tyre pressures should I have?

You want to use a pressure that gives you good handling and tire wear. This is pretty subjective, everyone tends to have their own opinion as to what works best.

Tire pressure is based on several things. You will notice that the tire manufacturer gives you a pretty wide range. You can't use max pressure on a car whose front end has no engine in it. You will be over inflated.
Wildthings is pretty much spot on. It matters what the weight of your particular vehcile causes the structure and contact patch of the tire to be shaped to.

Somr for instance:
On my 412 with about 200 lbs of junk in the trunk and a full tank, my 205-60/15 continental sport contacts used right at 32 psi for best handling.
Anything less ...like down to 28 psi on that profile causes side-wall roll and mushiness.
But....the same tires on my 90 cabrio needed 35 to 37 psi to keep the side walls up properly. But that car was front end and front transmission.

My bridgestones were stiffer sidewalls and required 35 psi on the 412 and about38-39 on the rabbit. Ray

Thanks guys, sounds a bit like trial and error.

Currently I have 19psi and it feels too heavy on the steering and the tyres look too slack(?). I'll raise it slowwly in increements till I find a suitable pressure.

Just raised my front tyre pressures upto 24psi and the rears upto 36psi and it is a lot better, I'll see how that goes for a few miles.

The car's handbook is wrong and it never made sense that the 412 should run with the same tyre pressures as the Beetle which is about half the weight. I ran my Fastback with 25 in the fronts and 30 to 35 in the rears (depending on what I was carrying) and it handled beautifully.

But see what you think with the higher pressures.

Judi

I have not found any modern radials...even and especially the original Michelin XZX's that were common on these cars...that operated correctly at less than 32 psi.
32 psi front and 35 rear is common on most radials. Its reverse on a front engine.
Radials have very stiff contact patch and softer sidewalls than bias ply tires....which is what the pressure in the book were made for. On a bias ply you could run lower pressure and still maintain sidewall rigidity. You must have higher pressures in radials. Ray

I've got a run out tonight on a training course so will see what it is like and put some more air in for the return journey for a comparison.