(ET) maximum grade

[Ken Olum <kdo cosmos phy tufts edu>]

What is the maximum grade that you can reasonably mow?  I have a hill
at the edge of my lawn down to the street that goes up to about 35%.
I think it's somewhat worse because the grass is in tufts with lower
ground between them.  If I try to mow across it I think I'm going to
tip over.  If I try to mow up it I lose traction.  If I try to mow
down it using either the motor or the brake (I have the upgrade) then
one wheel turns forward while the other turns backward and I slip down
the hill and wreck the lawn.

Would better tires help, or is this just too steep?

                         Ken