The data table below is data from Coker tire on alternate tire sizes. My 56 Dodge takes a 160-15 tire. I wanted an equivalent radial tire, so I compared available sizes and selected the nearest match. Overall diameter was a key data point because I did not want to alter the accuracy of the speedometer/odometer. The load rating exceeds the bias ply tire so safety is improved. Tread width is wider so that means there is the potential for less PSI on the road. This may not be a problem depending on what the % rubber per unit area there is between the tires. Looking at the tread design, it appears that there is about the same amount of rubber on the road because the radial has wider gaps between the tread and a wider tread. I highlighted my selected match. Did I pick the right radial equivalent? Tire Size Manufacturer/Model Construction UTQG Rating Overall Diameter Cross Section Tread Width Load Capacity 760-15 B.F.GOODRICH 3 3/8" WHITEWALL 4 ply polyester N/A 28.66 7.90 5.00 1710 @ 32 psi P215/70R15 BFGOODRICH SILVERTOWN® RADIAL 2 1/2" WW Poly/Steel 280-B-C 26.90 8.70 6.40 1620 @ 35 psi P225/70R15 BFGOODRICH SILVERTOWN® RADIAL 2 3/4" WW Poly/Steel 320-A-C 27.40 9.00 6.70 1753 @ 35 psi P235/70/R15 BFGOODRICH SILVERTOWN® RADIAL 2 3/4" WW Poly/Steel 320-A-C 28.00 9.50 7.0 1896 @ 35 psi P215/75R15 COKER CLASSIC 2 1/2" WHITEWALL Poly/Steel N/A 27.62 8.63 6.04 1742 @ 35 psi P225/75R15 COKER CLASSIC 2 3/4" WHITEWALL Poly/Steel N/A 28.29 8.95 6.24 1874 @ 35 psi P235/75R15 COKER CLASSIC 2 7/8" WHITEWALL Poly/Steel N/A 28.91 9.41 6.58 2028 @ 35 psi Ken Rimington 1956 Dodge Custom Royal |