Picked them up yesterday at Discount Tire. Quite a bit of difference between the 600-16 bias ply and the low profile 205/40 Radial tires. They both weigh 40 pounds, so there is no unsprung weight advantage. Comparison Old/New: 86/73.5 inch circumference. 736/862 revolutions per mile. 2782/3258 engine RPM at 60 MPH in 4th gear SWAG calculation. 4.5/8 inch tread width on the road.