For comparison, Coker's F78-14 bias tire has a tread width of 5.25", cross section width of 7.90" (0.65" wider than stock specs), and overall diameter of 27.06" (0.09" less than original specs). Firestone's Deluxe Champion bias-ply 7.50x14 has a 4.25" tread width, 7.52" cross section (about 1/4" greater than original design), and overall diameter of 26.89" (0.26" less than original). Goodrich Silvertown bias-ply tires, state that the 7.50x14 tire's tread width is 4.50", cross section width is 7.65", and the overall diameter is 27.02" (0.13" shorter than original specs).
Some basic dimensions, taken from Coker Tire's listing for B.F.
Let's look at this in more detail.įactory specifications indicate that the designed cross section width was 7.30", overall tire diameter was 27.15", and a loaded radius dimension of 12.6". So, right away we see that there is a discrepancy in tire sizes. According to a cross reference chart in Coker's catalog for radial versus bias ply tires, the 7.50x14 crosses with the F78-14 tire, while the G78-14 crosses with the 8.00x14 used on '62-'64 wires. Now, that's just the rim - now look at the tire dimensions.įor '57, the tire size was 7.50x14. The 5-1/2"-wide wheel sticks out 0.370" (or just shy of 3/8") beyond the original '57 specification. This means that if a '62-4-style (T-bird) rim is put on a '57, the rim would stick out further from the face of the brake drum/wheel hub. The offset distance (distance from center line of wheel to mounting face of rim center) would thus be 0.5625", and the distance from the brake drum/wheel hub to the front side of the rim would be 2.525" The stock rim would stick out past the face of the hub/brake drum 2.255"įor the '62-'64 (T-bird) wheel, backspacing is 3.75". But, there's more to this than the overall dimensions - there's also backspacing (distance from the back face of the rim to the center face, which sits against the wheel hub/brake drum) and offset (distance from center line of rim to backside face of rim center) to consider.īased on original specification drawings for a '57 and an estimated overall rim width of 5.75" across the rim lips, with a 0.62"offset from the wheel centerline this would mean the backspacing is 3.495", or a hair less than 3 1/2". Assuming the same 3/8" rim lip width on each side, the stock rim should be 5.75" wide.
The original rim size on a '57 was 14"x5", meaning the rim was 5" wide at the tire bead. That you're rubbing the tire on one side and the spinner on the other may mean that the axle housing is slightly off center, indicating frame damage from a prior collision or the axle was assembled to the springs either out of square or slightly to one side from the centerline of the car. The short answer is that some people trim back the bottom edge of the skirt to clear the spinner and tire. The clearance between the skirt and wheel/spinner for a '55-'57 may be less. The original spinners stuck out past the front side face of the rim (original '62-'64s could not be run with fender skirts if wire wheels were installed), while the reproductions have cut back the spinner height to allow them to fit behind fender skirts for '62-'64. The typical reproduction of the Kelsey-Hayes wire wheel, based on the '62-'64 wheel, is 5.5" wide, with 6.375" across the outside edges of the rim lips. Regarding the tire/spinner rubbing, this is going to be a long, developed response because many people don't understand the problem.
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