At 06:55 PM 6/4/2011, Rocket J Squirrel wrote:
>8 inches, more like, the height of the ramps. About 6 degrees, according

Ok, 550 lb instead of 350.  Where does the 550# gorilla sit?

Ok, if you insist on doing this...you can drill holes in the concrete
to take a couple of locating pins to rest each ramp against.  That
brings you down to 275 lb.  Now carry it a step farther.

Make a set of identical sub-ramps that match the driveway slope and
are long enough to carry the main ramps.  Eight holes drilled in the
concrete for 3/8" or 1/2" locating pins.  Now you can park the van on
the ramps and all the horizontal vector is taken up by the pins, even
though the van is still tilted six degrees.  Cover the two downhill
ones with diamond plate so your steel ramps won't sink in.  Two more
pins in each one to keep the plate in place and the steel ramps from
skidding.  *Now* when you drive down onto them you'll be level and
there will be no horizontal forces on the vehicle.  Three-foot ramps
would be 3 1/2" tall at the end; four widths of 4x4 spiked together
would give you 14" wide.  Or you could get them welded up from plate,
in which case a lip of plate at the end would restrain the van/main
ramp.  Or build from multiple layers of 1/2" plywood screwed and
glued with the long piece on top and the edges underneath chamfered
some so they don't crush.

There ya go, Mr. Squirrel.  Still no help when you need to raise a
wheel, but a start.  And you could extend the concept to make jacking
platforms for bottle jacks, stands etc..  If Mrs. S. doesn't like the
little holes, remind her how much less she'd like picking a van up off of you.

This doesn't mean I think it's a good idea, just a (much) less bad one.

Yours,
David