Date:         Wed, 9 Mar 2011 14:21:18 -0500
Reply-To:     The Bus Depot <vanagon@BUSDEPOT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         The Bus Depot <vanagon@BUSDEPOT.COM>
Subject:      Re: And now - still trying for NEW TIRES
In-Reply-To:  <AANLkTimZi3c0VHApBBE-KbJiPmr7a7aaGso6hLMkQgW-@mail.gmail.com>
Content-Type: text/plain; charset="US-ASCII"

> So the published data says that I need a tire that's rated
> for ~6% above the normal load for my van which is ~3990 lbs.?
>  And that passenger tires are good for my maximum load (5000
> lbs) plus 9% (450 lbs) ie 5450 lbs.?
>
> Good to know!  That means my 1709 lb winter passenger car
> tires and 1521 lb summer passenger car tires should be just
> fine according to Chicken Little?
>
> I made that decision all by myself some twenty years ago but
> thanks for the validation.  ;)


I'll ignore the childish name calling and just answer your queston
factually.

No, you are misunderstanding how to calculate this. If your passenger car
tire is rated at 1521 lbs, then it must be derated by 9% as per the D.O.T.
So you are starting off with 1384 lbs, not 1521.  That number must be higher
than the gross weight of the vehicle. Actually this is determined by axle
weight divided by two. On a 2 wheel drive non-camper the GAWR of the rear
axle is 2866 lbs, divided by two is 1433 lbs. If you have a Syncro it is
1521 lbs.  At 1384 lbs your summer tires are underrated. Your winter tires
at 1709 lbs (load index 99) minus 9 percent are adequate.

In ADDITION to this - not as an alternative to it - the standard load of
your van cannot exceed 94% of the above capacities - so 1301 lbs on your
summer tire and 1461 lbs on your winter tire.  The standard load is defined
as you plus two passengers plus a nominal amount of contents, assuming that
you do not exceed that weight on a regular basis. It would be higher on a
camper or Syncro due to supplied equipment.  According to Roadhouse.com, the
actual unladen rear axle weight of various measured Vanagons was around 2000
lbs (going up to 2600 on, for example, a Vanagon Syncro Camper).  Allowing
for, say, 800 lbs for 3 people plus belongings, which is slightly generous
but not over the top, this would be around 1200 lbs per tire for a standard
Vanagon  Your summer tire meets that condition if you have a non camper. But
it doesn't matter, because the tire must meet BOTH conditions, not just one,
and it falls far short of the first one.

I hope this clarifies things for you.

- Ron Salmon
  The Bus Depot, Inc.
  www.busdepot.com
  (215)  234-VWVW

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