ORIGINAL: Snipin_Willy
You wont see any improvement off-road. On-road purpose is to keep the tire sticky against the surface (asphalt or carpet), that would be bad for off-road unless you WANT dirt sticking to the treads instead of throwing it loose. Treads gummed up with mud sucks just about as bad as running bald tires.
You put it on about 20 minutes before so everything soaks in. At the end of my races there isnt any mud stuck to my tires, no more than without sauce.