Date: Mon, 16 Mar 2009 08:21:10 -0400
Reply-To: Mike S <mikes@FLATSURFACE.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike S <mikes@FLATSURFACE.COM>
Subject: Re: Reinforced tires - what about other vans?
In-Reply-To: <5ebe10a0903152048g6adccc9eja019ad2c03fe807e@mail.gmail.com >
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 11:48 PM 3/15/2009, Chris S wrote...
>What you folks can't see and refuse to admit is that with today's
>technology larger diameter tires of proper size can and do handle the
>weight loads of a Vanagon, a 3400 lb vehicle. I just looked up OEM
>tires for our 4310lb Honda Odyssey and the are rated at 1653 lbs at
>44psi.
It's hard to figure out exactly what you are now arguing.
You started by claiming that "1990 Mercedes 560 SEC...15'' Mercedes
tires and wheels are just fine," without provide ANY information on
what tires you were referring to.
Doing a search on tirerack.com for 1990 560SEL tires, the lowest load
rating shown is a 92-1389 lbs., which is insufficient for a Vanagon.
Now you're listing a bunch of other vehicles, the majority of which
have tires with a load rating higher than VW specified (100-1764 lbs. /
102-1874 lbs.).
Why did VW specify a reinforced tire? Because the Vanagon weighs more
than a car, and it needs stronger tires.
When the Vanagon came out, tires were spec'd differently - so VW
specified a 185R14C (load range C light truck tire) or a 185R14
reinforced (passenger car tire with higher than standard load rating).
"Reinforced" simply means that it had a higher load rating than normal
passenger car tires of the same size.
With modern tire markings, the "reinforced" and "extra load" markings
are somewhat redundant. You look at the load range number and use that.
For a light truck tire, you use the number directly, for a passenger
car tire, you should derate the load carrying capacity by 9% when used
on a Vanagon. (why has already been discussed)
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55
The lightest duty tire VW provided as OE on a Vanagon was a 97-1609
lbs. rated passenger car tire. That derates to 1464 lbs. That is the
closest match to the Vanagons GAWR (rear) of 2866 lbs. (divide by 2 to
get per tire requirement). The next step down, a 96-1565 lb. rating,
would derate to 1424 lbs., too low for the Vanagons actual weight
rating. That's not a coincidence.
A 100-1764 lb. load range passenger car tire, which derates to 1605
lbs., is fine, as long as it has a high enough maximum inflation
pressure (something 40+). A passenger car tire for an MB560, with a
load rating of 92-1389 lbs, which must then be derated to 1269 lbs, is
seriously under spec.