either 265/35 (.99 new to old ration) or 255/35 (1.00 new to old ratio)

245/35/20 and 285/30/20

Indicated speed: 10 mph. Actual Speed: 9.89 mph.
Indicated speed: 15 mph. Actual Speed: 14.8 mph.
Indicated speed: 20 mph. Actual Speed: 19.7 mph.
Indicated speed: 25 mph. Actual Speed: 24.7 mph.
Indicated speed: 30 mph. Actual Speed: 29.6 mph.
Indicated speed: 35 mph. Actual Speed: 34.6 mph.
Indicated speed: 40 mph. Actual Speed: 39.5 mph.
Indicated speed: 45 mph. Actual Speed: 44.5 mph.
Indicated speed: 50 mph. Actual Speed: 49.4 mph.
Indicated speed: 55 mph. Actual Speed: 54.3 mph.
Indicated speed: 60 mph. Actual Speed: 59.3 mph.
Indicated speed: 65 mph. Actual Speed: 64.2 mph.
Indicated speed: 70 mph. Actual Speed: 69.2 mph.
Indicated speed: 75 mph. Actual Speed: 74.1 mph.
Indicated speed: 80 mph. Actual Speed: 79.1 mph.
Indicated speed: 85 mph. Actual Speed: 84.0 mph.
Indicated speed: 90 mph. Actual Speed: 89.0 mph.
Indicated speed: 95 mph. Actual Speed: 93.9 mph.
Indicated speed: 100 mph. Actual Speed:98.9 mph.<ul><li><a href="http://www.web-cars.com/math/tiresize.html">http://www.web-cars.com/math/tiresize.html</a</li></ul>