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im getting new tires and was wondering if i could go from 255/75/17 to a 285/70/17. first of will those tires fit and also can someone explain what the first two numbers signify?
 

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im getting new tires and was wondering if i could go from 255/75/17 to a 285/70/17. first of will those tires fit and also can someone explain what the first two numbers signify?
Side wall will increase by .4 inches

Diameter will increase by .6 inches
 

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First number is the tire section width in Millimeters, second number is tire section height as percent of section width.
So a 285 is about 30mm (1.18") wider than a 255 tire ( 285mm-255 mm = 30mm ) and due to the added width may cause some rubbing at full steering lock or full suspension travel on stock wheels.

Overall diameter on the 285 is also slightly larger
255/75R17 --> 255 / 100 X 75 X 2 / 25.4 + 17 = 32.06" Diameter
285/70R17 --> 285 / 100 X 70 X 2 / 25.4 + 17 = 32.71" Diameter

Note numbers are only approximate and actual numbers vary in either direction from the indicated tire sizes depending on tire brand, tire type and wheel width the tire is installed on.
 

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Disclaimer

First number is the tire section width in Millimeters, second number is tire section height as percent of section width.
So a 285 is about 30mm (1.18") wider than a 255 tire ( 285mm-255 mm = 30mm ) and due to the added width may cause some rubbing at full steering lock or full suspension travel on stock wheels.

Overall diameter on the 285 is also slightly larger
255/75R17 --> 255 / 100 X 75 X 2 / 25.4 + 17 = 32.06" Diameter
285/70R17 --> 285 / 100 X 70 X 2 / 25.4 + 17 = 32.71" Diameter

Note numbers are only approximate and actual numbers vary in either direction from the indicated tire sizes depending on tire brand, tire type and wheel width the tire is installed on.
Very Nice Disclaimer at the end! I like it. :D
 

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I have 285X70X17 GY MTR mounted on moab wheels. Minor rub at full turn, but this can eliminated with spacers. The only lift I have is springs off a JKU Rubicon, gives me 1.5" of lift.

Doors Off.JPG
 
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