I will contribute to this thread.

3400 pounds in a tall narrow package does not equal 3400 pounds in a
wide squat package.

The Vanagon is taller and narrow than vehicles of comparable weight
and sits on a narrower wheel base. Because of this shape, if/when a
tire deflates a larger amount of mass at a higher point above the
road, is getting shifted.

As anyone who has used a fulcrum should know, it is easier to move
things with a longer arm. That extra height of the Vanagon makes it
easier to flip it over, if it has a bit of impetutus, such as a tire
blow out.

On Mar 14, 2009, at 10:50 AM, Chris S wrote:

> This is the only compelling argument I've read so far against using
> M-B sufficient tires on the Vanagon.  Good job.
>
> 2009/3/14 The Bus Depot <vanagon@busdepot.com>:
>> Chris S., quoting long glowing GoWesty ad for Michelin HydroEdge
>> 15" car
>> tires, concludes...
>>
>>> Yes, 14'' passenger tires are deadly on a fully loaded Westy.
>>>  I'm not talking about 14'' tires.  Again, I quote "... they
>>> provide WAY better handling and safety."
>>
>>
>> GoWesty's claim directly contradict both Volkswagen and the U.S.
>> D.O.T.  As
>> per VW, using 15" or even 16" tires does NOT eliminate the need for
>> an
>> extra-load tire. The Eurovan, for example, has about the same GVWR
>> as the
>> Vanagon and came factory equipped with 15" and 16" tires.  Yet VW
>> specified
>> ONLY extra-load tires in both 15" and 16" sizes. The same applies
>> to the
>> current model T5 van, and even to earlier Buses that came equipped
>> with 15"
>> tires (and weighed less than Vanagons).  In fact NEVER has Volkswagen
>> recommended passenger-car rated tires for their vans, no matter
>> whether 14",
>> 15", or 16".  If you do the math regarding D.O.T. safety
>> requirements for
>> Vanagon tires, as explained at http://busdepot.com/details/
>> tires.jsp, you'll
>> see that federal regulations also prohibit the use of standard-load
>> passenger car tires - regardless of size - on VW vans.
>>
>> Volkswagen did not just randomly come up with the minimum specs for
>> tires on
>> the Vanagon. Such specs are based on solid engineering and testing.
>> The fact
>> that they continuously tweaked recommended inflation over the years
>> indicates that they also revisited the issue periodically - but
>> over 40
>> years, NEVER ONCE waivered from their insistance that extra-load
>> tires must
>> be used.
>>
>> So, you can rely on Volkswagen's own engineering, or the unproven
>> advice of
>> a retailer who has a vested interest in your ignoring factory safety
>> recommendations (they want to sell you their wheels/tires, which
>> don't meet
>> VW specs). Given that it is possible to buy appropriately rated
>> Vanagon
>> tires in all sizes, why on earth would you take this risk?  Might
>> as well
>> stop wearing your seatbelt too. If Volkswagen turns out to be right
>> after
>> all, it will be during evasive maneuvers (when most of the weight is
>> transferred to one wheel) when you will find out. In other words
>> you'll find
>> out the hard way as your van flips over. But at least while you see
>> your
>> loved ones being crushed or ejected from your Vanagon, you'll have
>> the
>> comfort of knowing you saved a few bucks on tires.
>>
>> - Ron Salmon
>>  The Bus Depot, Inc.
>>  www.busdepot.com
>>
>
>
>
> --
> Chris S.
> Disclaimer: "Death and serious injury may occur"