In article ,
says...

On Wednesday, June 12, 2013 10:04:24 AM UTC-4, iBoaterer wrote:

So, you now have a car with 4 times the mass using about the
same tire contact area as the motorcycle.

BS. Cite?

http://www.porsche.com/international/models/911/911-
carrera/featuresandspecs/
(140kg laden weight)

http://en.wikipedia.org/wiki/Ducati_848
(Dry weight 370 pounds, so if you take it's laden weight of say 600
pounds we're close)

BTW... like many sports and race cars, my old Boxster's rear tires had a lot of camber to allow the tire to have better contact with the road when in a high speed turn. Wears out the inside edge quickly, but increases grip dramatically. That big, flat patch of rubber stays on the pavement.

Bikes can't have flat surfaced tires, so their contact patches are very small all the time.

Oh, now you want to talk specialty cars, but street motorcycles!!!!!
Well, the contact are for a road course motorcycle is large as well for
just that purpose. Plus, you've forgotten that pesky physical fact that
you are trying to turn 4 or 5 times the mass of something that wants to
go straight.