Some Vanagon.com listees have been claiming that low-profile
performance tires cannot handle the mass of our vans.

Well, I just bought a set of nice 18" ANZ Scars fitted with 225/35/18 Hankooks.

Here are the hard figures:

wheel static load rating 680kg (1496lb)

tire lstatic oad rating 545kg (1021lb) @ 340kPa (50psi)

A fully-loaded Type 2 grosses at what, 2.5 tonnes/5500lb? Dividing
this by 4 gives static 625kg/1375lb per wheel (as we all know, the T3
has a 50:50 front:rear mass-balance).

The wheels are more than capable of holding up. These particular
tires will carry a reasonably heavily-loaded bus... and face it, how
many of us ever load them up fully? ... and don't forget, these
manufacturers' figures will have a fat ass-covering safety margin
built-in.

These are far from high-end tires and are made for average cars;
similar tires designed for large cars will carry a fully-loaded bus
with capacity to spare.

Jeez, but there isn't a lot of meat on those tires to let pressures
go down through lack of checking...