From the Syncro owners manual supplement -

Wheels and Tires

All four wheels on the vehicle must always
have tires of the same size, construction
and tread type so that the viscous
coupling does not abnormally activate the
front wheel drive. Different tires on the
front or rear wheels exert additional stress
on the drive train components, causing
increased tire wear and impair vehicle
control.

Volkswagen makes the point that all four tires must have the same size and
construction. Hard to imagine that 6 & 8 ply tires would have the same
"construction". The other difficulty with different tires on a Syncro would
be rotating them to achieve equal wear. Those 6 plys would have to wind up
on the back at some point.

Angus

On Mon, Jan 20, 2014 at 4:46 PM, James <jk_eaton@hotmail.com> wrote:

> Would 185R14C 6PR and 185R14C 8PR be different diameters?  Usually 185R14
> tires are all the same outside diameter, aren't they?  I thought the 6PR
> and 8PR only referred to the internal construction.
>
> Not questioning your wisdom, just want to better understand tire
> placarding.
>
> James
> Ottawa, ON
> '91 2wd Vanagon Weekender Westfalia
>
> > Date: Mon, 20 Jan 2014 15:28:14 -0800
> > From: birdworks@GMAIL.COM
> > Subject: Re: Volksiebus - 88 Transporter - Rough Running Engine
> > To: vanagon@GERRY.VANAGON.COM
> >
> > >
> > > and if no one believes me about D's in the rear, C's in the front..look
> > > at a syncor tire pressure sticker sometime.
> > > says right on it ...rear 8PR, front 6PR.
> > >
> > >>
> > >>
> >
> > Actually it doesn't say that at all Scott - bad advice.
> >
> > Run what you want on a 2WD, but a Syncro's tires should obviously all be
> > identical if running a stock drive-train. Here's a photo of my Syncro
> > sticker -
> >
> > <
> >
> https://picasaweb.google.com/lh/photo/Cj48oPtaMjQ3hxDdKrMhLtMTjNZETYmyPJy0liipFm0?feat=directlink
> > >
> >
> > Notice on the first two lines there is no horizontal line between 185R14C
> > 6PR and 185R14C 8PR. This means they both use the same front/rear
> pressures
> > to the right. The horizontal line has a meaning.
> >
> > Using your logic I could use 205/70R1497R tires on the front. and
> > "reinforced" on the back (see sticker).
> >
> > I'm sure your Syncro customers don't run different tires front and back -
> > do they?
> >
> >
> > Angus
>