I am looking at tire company websites and checking out the size tires they have available. and I keep seeing stuff like this 33X12.50R17LT. What the crap is this? Is this bigger or smaller than a 285/70/17? :mecry:

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I am looking at tire company websites and checking out the size tires they have available. and I keep seeing stuff like this 33X12.50R17LT. What the crap is this? Is this bigger or smaller than a 285/70/17? :mecry:

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7,381 Posts

Google tire size calculator. They give u a good comparison of different tire size, width, height.

Take the 285 (that's milimeters) and divide it by 25.4 that will give you approx. 11.25" That's how wide the tire is. Take your 11.25 and times it by .7

That gives you about 7.875 now that is just for one half of the side wall. So now you need to times the 7.875 x 2 that's 15.75 now add the rim size to that (17) and you have about 32.75.

So a 285/70/17 is about a 33x11.25x17. Hope that helps.:cheers:

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4,384 Posts

Pretty straight forward. 33 is the heigth, 12.50 is the width, R is radial, 17 is the rim size, LT is Light Truck. This is the old school way tires were descibed before metric tires became popular.

I am looking at tire company websites and checking out the size tires they have available. and I keep seeing stuff like this 33X12.50R17LT. What the crap is this? Is this bigger or smaller than a 285/70/17? :mecry:

Just a bit smaller than the 285/70/17 which I assume will also be a radial.

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2,555 Posts

The first number on the metric sizing is the width of the tire in millimeters. Take it and divide by 25.4 to convert to inches. So 285/25.4 = 11.2 inches. That's the tire's width.

Multiplying the width by the second number in the metric sizing (which is the sidewall ratio and is expressed as a percentage) gives you the distance between the outer edge of the tire and the rim, or the measurement of the sidewall. So 285 x 70% = 199.5 millimeters. Again, to convert to inches divide by 25.4, so 199.5/25.4 = 7.85 inches. Now to determine the overall diameter of the tire, you must take the sidewall measurement, add in the rim size (which is the third number in the metric sizing and is actually measured in inches, so in this case it is 17 inches), and then add in a second sidewall as the rim has sidewall surrounding it (e.g., the diameter of the tire itself would consist of the measurement of two sidewalls and the diameter of the rim). So you have 7.85 inches (sidewall) + 17 inches (rim) + 7.85 inches (sidewall) = 32.7 inches.

So 285/70/17 = ~32.7 inches in diameter x 11.2 inches in width. The rim size is 17 inches.

Hope this helps.

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73 Posts

So 285 / 10 (convert to cm) = 28.5cm

28.5 / 2.54 (convert to inches) = 11.22"

11.22 * .7 (calculate sidewall height) = 7.85"

So a 285/70R17 would be 11.22/7.85R17

If my understanding or my math is wrong, please feel free to correct me

-cad

Tire Size Calculator - tire & wheel plus sizing

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16,781 Posts

No, i think someone misspoke right above you.ahh ok. I knew it was a measurment in inches, but I didn't understand how he measured up to the normal measurments. So I relly couldn't tell if it was larger or smaller than the 285/70/17.

So the 33x12.50x17 is slightly smaller?

The 33x12.50 is slightly taller and an inch wider than a 285.

ohh ok. Will a 3" and BC fit 33x12.50x17?No, i think someone misspoke right above you.

The 33x12.50 is slightly taller and an inch wider than a 285.

Thanks

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16,781 Posts

On stock wheels definitely.ohh ok. Will a 3" and BC fit 33x12.50x17?

Thanks

Aftermarket wheels depends on the backspacing.

You might rub the UCA. Other than that you should be ok. That is assuming you are on stock wheels.:cheers:ohh ok. Will a 3" and BC fit 33x12.50x17?

Thanks

You might rub the UCA. Other than that you should be ok. That is assuming you are on stock wheels.:cheers:

Yeah the stock 17" alloys.

I was looking at the General Grabber AT2 tires in that size.

I have 285/70/17 on mine and they were real close to the stock UCA. That would be my only concern on that size. You could upgrade to aftermarket UCAs or run wheel spacers if it's a problem. I have upgraded my UCAs and have tons of room now.:cheers:

I wish I was a fabricator. The gear for this rig is expensive. I would deff. like some UCA's and spacers, and lower rear top and bottom control arms as well. I may have to take a small loan for this stuff lOL :rofl:

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