Date: Mon, 01 Apr 1996 11:21:00 -0800 (PST)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: "Maher, Steve (SD-MS)" <SMAHER@gi.com>
Subject: RE: 83 diesel tires...Yes or No.
>Can I put 205/70's on my diesel? Some say sure, some say expect disaster.
>I'm confused...yes or no.
Some VW vans offered 205/70R14 tires as options from the factory, so
they should fit.
>Can I use a high load rated tire instead of a "reinforced" tire?
Officially no, but lots of people do it, including moi. The V6anagon
has 215/75R14s on it, which clear the fenders/suspension fine, and if
I keep the tire pressures just right the high-speed handling is excellent.
BUT... if the pressures are a little off, it gets squirrelly, and blows
around a LOT in gusty winds. Since the tires are larger than what VW
intended, the load ratings are higher, so I'm not much worried there.
I just finished a 1,000-mile road trip with six people and luggage, and
had zero tire problems (losing the clutch was an unrelated matter).
Steering forces while stopped and/or parking, are pretty heavy, though.
I'm told that using reinforced-sidewall tires like that lone Continental
you mentioned, would help this a lot. So would getting some exercise,
probably. I haven't done either, and it shows.
>Will it handle okay if I do this?
You have to be REAL careful with tire pressures. My 215/75R14 passenger-car
tires are rated at 35 PSI max. I had 35 in the rears and 30 in the fronts,
and it was kind of squirrelly. Clearly the V6anagon didn't get along too
well with these tires. I changed it to 37 rear/ 27 front, and it smoothed
out wonderfully, even with 1,000 pounds of people and luggage. Don't try
this at home, kids-- I am a professional, and sometimes not quite right
in the head, which is a necessary requirement for driving on overinflated
tires.
If I had it to do over again, I'd go with the reinforced Michelin 185R14s
I've heard of on this list. I've often found that stronger tires have higher
permissible max pressure ratings, which allow greater disparities between
front and rear-- recommended by VW on the sticker inside the driver's door,
and also borne out by experience. With ordinary passenger-car tires, you
can't get the differential you need, without either overinflating the rears
or underinflating the fronts-- unhealthy in either case.
>Does the "s" in 185/75 sr 14 mean sidewall reinforcement. I don't think
>it does but I've been told it does and it doesn't...I'm confused...a guy
>at a tire store said it stands for standard.
I hope that guy was a good salesman, because he doesn't know jack about
tires. "SR" is the tire's speed rating. It specifies the maximum speed
the tire can run continuously, with the max load and pressure specified
on the sidewall of the tire, without overheating.
SR = 113 mph
HR = 130 mph
VR = 150 mph, I think
ZR = "greater than 150".
No rating letter, like 185R14, means 93 mph.
There are other letters like TR, that I can't remember the speeds for.
*Knowlegeable* tire shops can tell you what they are. If you exceed your
SR rating for long periods of time, tires will be the least of your
problems! :^)
Tires generate heat mostly by the flexing and unflexing of the sidewall as
the car rolls onto a given patch of tread and rolls off it while moving
forward. The faster you go, the more flexing (obviously), and the more heat
you generate. Also, if your tires are underinflated, they'll flex a lot
more, generate more heat, and can fail catastrophically. I had that happen
on a '69 bus with a slow leak that I was too lazy to get fixed. A front
tire went bye-bye on a freeway at 65 mph. If it had been a rear, I probably
wouldn't be writing this. It's not a pretty sight.
If I were you, I'd shop around for four Michelin 185R14 *reinforced* tires,
and keep that Continental for a spare. Prices seem to vary widely, from
reasonable to outrageous, for the same tire. Don't bother with the Road
Hazard Warranty unless they throw in free lifetime spin-balancing. Put
the pressures into them that VW lists on the sticker inside the jamb of
your driver's door, no matter how weird they may seem-- VW had good reason
for recommending them. Change pressures only if you have a real good reason
like very heavy loading.
Good luck!
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Steve Maher smaher@gi.com '80 V6anagon w/Chevy 2800
'66 Mustang Coupevertible, for sale
Check out the cars at http://www.lookup.com/homepages/76242/home.html
*** I'm a Native American, born in Illinois. Or does ancestry
make a difference after all? ***
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