Date: Wed, 5 Mar 1997 12:11:06 -0500 (EST)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: SyncroHead@aol.com
Subject: Tire rating & selection (was: RESULTS - Tire Survey)
In a message dated 97-03-05 10:35:45 EST, kfairey@oit.umass.edu (KENYON
FAIREY) writes:
<snip>
> There were NO Sport/light truck tires listed at this size. There appeared
to
> be only:
>
> 205/75 SR 14 and
> 215/70 HR 14
>
> tires listed in this catagory.
You can also use the Light Truck tire size: 27x8.50LT - R14. I'm not certain
at the moment where they throw the LT into that size string, but you get the
idea. I, and many other Syncro owners, use this size on our Syncros.
> Another question - I know that 'SR' means 'sport radial'
Actually not. The letters that preceed the R are the speed rating of the
tires. I'm not certain of the exact values, but they're something like this:
S: 100 MPH
H: 120 MPH
V: 135 MPH
and so on... On a Vanagon, you should never need to worry about the speed
rating unless you're going down a big hill and are crazy enough to let the
van go that fast!
> and that 'R' simply
> means 'radial'. I also believe that the 'P' before the id means
'passenger'
Yes. P is for Passenger vehicles.
> I do not know the meanings of 'VR', 'HR', and 'TR'. I'd rather not guess.
> None of the tires state that they are reinforced. And, are the 'Orig Eq'
> tires actually tires that meet specs for being shipped on vehicles from
> manufacturers
> My local tire man has told me that "original factory tires ALWAYS wear
> better and longer than ANY replacement tires." Is he correct? If so,
shouldn't I
> go for that choice?
I don't believe that to be true. When a manufacturer selects a tire the
primary considerations are cost and then a combination of comfort (a softer
tire body) and road feel/performance (a harder tire body with a softer tread
compound). I think the length of time the tire will last (longer lasting
tires have harder tread compounds) is way down on their priority list. Even
if he were correct, the longevity of the tire is only one consideration. The
tire's ability for traction is particularly important while braking and
cornering. A tire with good traction performance could stop 20' shorter than
a tire designed primarily for long life. That could make the difference
between a 20MPH collision and a near miss! Other factors are the wet
traction performance, comfort of the ride, and tire noise. Building a tire
is quite a balancing act between many competing factors.
The primary considerations for a Vanagon tire are safety related: maximum
pressure rating and the maximum load carrying rating.
1. Look in your door jam for the recommended pressures for tire size you're
getting and make sure that the tire's maximum pressure rating exceeds this
number.
2. Next, make certain that the maximum load that the tire can carry is above
the load you expect to apply. Your Westy probably weighs about 4,000 lbs
empty. Load it up with people & cargo and it's likely anound 5,500 lbs.
That's roughly 1375 lbs per tire. To add some room for error and allow for
uneven tire weighting, the minimum tire load rating that's safe on your van
is about 1500lbs. More would be better.
Some tires that don't specifically say "reinforced" (like many LT tires) may
still be able to handle these pressures and load ratings. The tire does not
have to specifically say "reinforced" to meet these criterion. On the later
model Vanagons, Michelin was able to make a "reinforced" version of their
normal MXL tires to meet the requirements for heavier vehicles like the
Vanagon. Some tires are constructed from scratch for these higher loads.
3. After you've found tires meeting those two safety requirements, you can
begin to consider the subjective qualities of traction, ride, longevity,
noise, and cost.
Good luck,
Jim Davis
87 GL Syncro
88 GL Wolfsburg