Need help with tire measurements

[chugbug]

What's a formula for figuring out tire size??
Like a 275/65/18? Is it 275mm high/65mm wide or ?? I'm a bit cornfused lol. Thanks for your help

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05 2500, 48re, straight piped, ranch hand bumpers, patriot blue, moto metal 959s 33" maxxis big horn m/ts. Next mod is stacks,tranny, then smarty.

[smokin24valve]

Originally Posted by chugbug

What's a formula for figuring out tire size??
Like a 275/65/18? Is it 275mm high/65mm wide or ?? I'm a bit cornfused lol. Thanks for your help

-275mm(10.83 inches) widest point of tire
-65 is the percentage of the width of the tire = side wall height
18 is rim size

275/65/18

275/25.4(# of mm per inch)=10.83
10.83*65%=7.06

10.83" width
7.06" side wall height

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James
96 1500 RCSB 4x4 12v in the works

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Last edited by smokin24valve : 09-17-2009 at 04:29 PM.

[Mopar99360]

This link makes it easy for me.
Tire Dimensions Made Simple - Discount Tire
Scott

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05 Blu QC 2500 4X4, Auto, XDI, Exht (Wifes Rig), 05 Wht QC 2500 4X4, 6 spd, S&B, Exht: (My Rig)

[knalb]

Yep, you can do the math looking to see how much bigger over stock your new stuff is going to be, or you can thank some Miata guys for doing it for you:

Tire size calculator

Hmm, the one Mopar99360 had in is similar, but I've always used the Miata calc so I'll leave it here as well.

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2006 QC SB 4x4 Atlantic Blue SLT

[chugbug]

Thanks so much guys. It just made no sense whatsoever to me and now it does. I guess I guess it must be more precise.

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05 2500, 48re, straight piped, ranch hand bumpers, patriot blue, moto metal 959s 33" maxxis big horn m/ts. Next mod is stacks,tranny, then smarty.

[BillyRam]

Just remember when you mount and inflate tires you can end up with less height. A tire that may show to be 32.4" on the calculator may only be 31.25" mounted and inflated.
Billy

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Garmon tranny SunCoast ProLoc
HTT ProStreet 66/71/13
652hp/1254tq=11.91/111.59-1/4