81 F100 Bolt Pattern

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02-13-2005, 07:29 PM

sinchicken

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81 F100 Bolt Pattern

This has probably been asked many times before, but can someone tell me what the lug pattern is for an 81 F100. I read somewhere it was 5x139, but I would like to make sure. Thanks in advance.

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02-14-2005, 06:42 AM

82F100SWB

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If the truck has manual brakes, it's 5x5.5", if it has power brakes, it may be 5x4.5" instead.

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02-14-2005, 11:20 AM

sinchicken

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Thanks.

It has power brakes.

Forgive me for my ignorance, but how do you measure it?

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02-14-2005, 02:53 PM

Boss50

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My '81 has power brakes and has 5x5.5 bolt pattern.

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02-14-2005, 03:15 PM

mtflat

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Measure from the center of one stud to an imaginary arc running between the opposite two bolts. The difference of an inch will be obvious.

Ford didn't go with a metric pattern until 1997/98

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