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::newbie:: can someone explain tire sizes??

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Old Jan 5, 2013 | 09:55 AM
  #1  
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Default ::newbie:: can someone explain tire sizes??

I'm looking for a 35 inch tire and I can't seem to find the difference between 35x70x17 and 35x12.5x17 except the price? Maybe I'm just retarted and don't understand something. If you guy/ girls could explain that be great!
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Old Jan 5, 2013 | 10:05 AM
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There are calculators online you can google to better help you understand. All tires are different. What may be stamped a 35 might not be a 34. What helped me I would get the specs of the tire from manufacturer which would tell me the true size. If you get in tire section on Quadretec's site and go to different brands they will show you the true sizes of the tires. I hope this helps you a bit.
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Old Jan 5, 2013 | 10:13 AM
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35x12.5x17 will be roughly 35" tall, 12.5" wide, fit on 17" wheel.

315x70x17 will be 305 mm wide at the tread, 70 mm tall on top of tire, 70 mm tall on bottom of tire, fit on 17" wheel.

When that sizing metric, you'll add 70mm on top + 17" for the wheel + 70mm on bottom and you'll = about 35" tall.

These are rough measurements meant to be an example, different tires say they're the same size, but manufactures don't all follow same specs.
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Old Jan 5, 2013 | 10:14 AM
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Yep x2 on that and once they are mounted on the Jeep you will lose a little in hight as the weight of the Jeep.
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Old Jan 5, 2013 | 10:25 AM
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35x12.5x17 will be roughly 35" tall, 12.5" wide, fit on 17" wheel. Correct

315x70x17 will be 305 mm wide at the tread, 70 mm tall on top of tire, 70 mm tall on bottom of tire, fit on 17" wheel. The tire will be 315mm wide at the same point as the 12.5" is wide, 315mm = 12.4"

When that sizing metric, you'll add 70mm on top + 17" for the wheel + 70mm on bottom and you'll = about 35" tall.The 70 is 70% of 315mm or 220.5 mm

So, 17"+ 220.5mm + 220.5mm = roughly 34.36" but you need to check each manufactures spec.

These are rough measurements meant to be an example, different tires say they're the same size, but manufactures don't all follow same specs.

OF COURSE THERE WILL BE A FLAT SPOT WHERE THE JEEP MEETS THE GROUND SO A 35" WILL BE CLOSE TO 34" MOUNTED AND WEIGHTED.

What you need to do is decide what size you want or need as not to rub, it doesn't matter whether the size is metric or American. Cost is usually based on demand so you will find that the American sizes are more common therefore cheaper.

Last edited by Mschneid; Jan 5, 2013 at 10:33 AM.
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Old Jan 5, 2013 | 10:30 AM
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Here's everything you'll ever need to know about tires........


Info Center - Discount Tire Direct
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Old Jan 5, 2013 | 10:33 AM
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You have actually combined the pmetric sizing with the English or standard inches in your op. 35x12.5x17 is the inches style of labeling tires. 35" tall, 12.5 " wide, and 17" wheel diameter.

The pmetric system is where you see something like 305/70/17. These numbers mean 305 mm wide, 70% of 305 is sidewall height, and 17 is wheel size again. So in this example, 305 mm wide is 12.00" wide. 70% of 305 is 213.5 divide that by 25.4 to convert to inches and you get 8.40" as your sidewall height. 17 is still the wheel diameter. Add the heights together and you get total tire height in inches. 8.4 + 8.4 + 17 = 33.8" tall.

Clear as mud?
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Old Jan 5, 2013 | 10:35 AM
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Beat me to it. Lol.
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Old Jan 5, 2013 | 10:54 AM
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Originally Posted by bountyhunter
You have actually combined the pmetric sizing with the English or standard inches in your op. 35x12.5x17 is the inches style of labeling tires. 35" tall, 12.5 " wide, and 17" wheel diameter.

The pmetric system is where you see something like 305/70/17. These numbers mean 305 mm wide, 70% of 305 is sidewall height, and 17 is wheel size again. So in this example, 305 mm wide is 12.00" wide. 70% of 305 is 213.5 divide that by 25.4 to convert to inches and you get 8.40" as your sidewall height. 17 is still the wheel diameter. Add the heights together and you get total tire height in inches. 8.4 + 8.4 + 17 = 33.8" tall.

Clear as mud?
I donnow... is your mud clear?
But surely, so far, yours is the only correct explanation.

Also --
35/12.5/17 (inch) is supposed to be the same size as 315/70/17 (metric, calculated diameter = 34.36"),
but, these numbers are nominal, and not the accurate tire diameter.
The same 35/12.5/17, or 315/70/17 size, from different makes, would somewhat vary in actual size,
which will typically be a bit less then the numbers show.

Last edited by GJeep; Jan 5, 2013 at 11:19 AM.
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Old Jan 5, 2013 | 11:27 AM
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Ok so basically I need to find the tire I want and figure out the true tire size. Once iv done that it doesn't really matter if its a 35x12.5x17 or 35x70x17 because that essentially means its that same size tire? Did I get that correct lol?
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