What Tire Size Replaces an Old A78-13 Tire Size

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Question:

ON A 1974 SPITFIRE. replacement size

asked by: BOB

1

Helpful Expert Reply:

The modern metric equivalent to tire size A78-13 is going to be a 175/80-13. You won't be able to use any of the tires we carry though because they are for trailer use only.

There is a difference between the way trailer tires are manufactured versus passenger vehicle tires. Trailer tires are built with a thicker sidewall to handle more vertical load. Passenger tires are built for cornering more with lateral forces in mind.

expert reply by: Michael H

1

Answer 1

If you think of the back of the trailer as flat and straight left to right, and the sides of the trailer flat and straight front to back, where they meet in the corner would be a right angle. If you were to mount the light in that corner, so that it…

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Answer 2

The metric equivalent of an A78-13 tire is a 175/80-13. This size is available in load range B, #AM1ST74, rated for 1,100 pounds at 35 psi. It also comes in load range C, #AM1ST76 for bias ply or #AM10199 for radial, both rated for 1,360 pounds at 50…

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Answer 3

The new equivalent of tire size A78-13 is 175/80-13. This is the exact same size, so there should not be any interference at all with your fenders that fit the A78-13. I went ahead and attached a FAQ article and table that shows this translation. As…

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Answer 4

Trailer tires of the ST78-13 size have not been in common use for several decades but when they were made their actual widths were not standardized the way tire sizes are today. There were in fact 4 different widths made with this same designation;…

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Answer 5

The grease seal you need is the part #13194 which has an inner diameter of 1.372 inch and an outer diameter of 1.983 inch.

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Answer 6

The difference between the single lip and double lip seals is that the double lip grease seal will have two rubber lips that are in contact with the spindle. The double lip grease seals are usually used in marine applications to give a better seal…

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Answer 7

The modern equivalent of the A78-13ST is ST175/80-13. Since that size will not work for you the only option is to go to a 12 inch tire and wheel. The other places must have only had a limited selection because you can get a 145/80-12 with a capacity…

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Answer 8

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

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Answer 9

According to Blue Ox, it'll take an experienced installer about 4 to 5 hours to complete the installation of their #BX1128 Base Plate Kit on a 2016 Jeep Grand Cherokee. The install isn't what I'd call super-difficult, but the installation…

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Answer 10

The 5.30-12 tires, being wider, are going to make more contact with the road. This means that the noise, and heat build up will be higher than a 4.80-12 tire but the rolling resistance will actually be less because the tire is larger diameter. The…

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Answer 11

The #84 spindle is just a common way to identify the spindle dimensions typically used for 3,500 lb axles. So instead of listing out the parts, people can just say they have #84 spindles and it's easier to know what fits it. The CE Smith Trailer…

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Answer 12

The difference between an load range C and load range D tire in the same size is the capacity and psi rating. The two tires will still have the same dimensions and fit on the same wheel. The D rated tire has a higher capacity. For a ST175/80D13 like…

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What Tire Size Replaces an Old A78-13 Tire Size

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