I tow a large trailer which carries both my Salto sailplane
and my Skybolt biplane behind a Dodge Ram 2500. When
I changed tires a couple of years ago, they inadvertently
installed 8 ply (load range D) instead of 10 ply (load
range E). The towing characteristics went from excellent
to scary. The tire shop fixed the mistake, and all
is well again.

If you are towing a sailplane trailer at 75 MPH behind
a VW Passat, let me know where you're going, so I can
be sure to stay far away. IMHO, not nearly enough
tow vehicle mass, regardless of tires.

At 05:30 03 February 2005, Papa3 wrote:
I recently replaced the Original Equipment Michelin
MXV4 H-rated tires on my
VW Passat 4 motion wagon (Variant for those of you
in Europe) with Dunlop SP
40 A/S all weather radials. Other than lacking a speed
rating, they are the
same dimensions as the originals. Although the
new tires are okay in
regular driving, I've noticed that the towing performance
is much worse.
The car and trailer combination (LS8 in a new Anschau
Komet Euro Trailer)
used to be rock solid up to 75mph; any mild trailer
wag would damp out
immediately. Now, trailer wag can set up at around
65mph, and it seems
less likely to damp out.

I'm assuming that one aspect of speed rated tires must
be a stiffer sidewall
to handle cornering loads. I'm guessing that this
may be a part of the
problem. Anyone else experience similar?

Erik Mann (P3)