>Even though I probably could get up to that speed with my SVX Vanagon,

No doubt about it, even with stock gearing.

>I'm not sure my tires are rated for that speed. Hence, I'm unlikely to
>even try.

Any tire will do OK at that speed for a short burst; it's prolonged
speed that damages low-speed-rated tires. Flexing of the sidewalls
causes internal friction and this procduces heat, which can cause the
rubber to "go off". I experianced this on my Honda CBX running a
Dunlop Arrowmax. The tire tread surface started to pill badly. Then I
took it on a racetrack and really heated it up (this time by
cornering and accelerations rather than speed); the rubber really did
go off, the tire became slippery and never recovered.
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<andrew.grebneff@stonebow.otago.ac.nz>
Seashell, Macintosh, VW/Toyota van nut