Mudder
Senior Member
So ok, I'm trying to figure what wheel and tire setup to go with on my truck. And so taking two sizes that seem very different but in actuality sit the same on the truck. Check my math, see if this is right.
So let's take a 17x8 0 offset wheel. And an 18x9 0 offset wheel. Both running 12.5" wide tires.
Backspacing on the 17x8 is 4.5. So if you add that to the split of the overhang of the tire (12.5-8=4.5/2=2.25) the sidewall of the tire sits 6.75" from the mounting point. Using the same formula, the outer edge of the sidewall sits 5.75" from the mounting point i.e. hub.
Backspacing on the 18x9 is 5. So if you add that to the split of the overhang of the tire (12.5-9=3.5/2=1.75) the sidewall of the tire sits 6.75" from the mounting point. Using the same formula, the outer edge of the sidewall sits 5.75" from the mounting point i.e. hub.
So essentially the two setups would sit exactly the same on the truck from a clearance perspective despite it seeming like you'd have more room with the 8" wheel having 4.5" backspacing.
What a confusing cluster this is turning into for me. And yes, I've been known to overthink things.
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So let's take a 17x8 0 offset wheel. And an 18x9 0 offset wheel. Both running 12.5" wide tires.
Backspacing on the 17x8 is 4.5. So if you add that to the split of the overhang of the tire (12.5-8=4.5/2=2.25) the sidewall of the tire sits 6.75" from the mounting point. Using the same formula, the outer edge of the sidewall sits 5.75" from the mounting point i.e. hub.
Backspacing on the 18x9 is 5. So if you add that to the split of the overhang of the tire (12.5-9=3.5/2=1.75) the sidewall of the tire sits 6.75" from the mounting point. Using the same formula, the outer edge of the sidewall sits 5.75" from the mounting point i.e. hub.
So essentially the two setups would sit exactly the same on the truck from a clearance perspective despite it seeming like you'd have more room with the 8" wheel having 4.5" backspacing.
What a confusing cluster this is turning into for me. And yes, I've been known to overthink things.
Sent from my iPhone using Tapatalk