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I've got all kinds of conflicting info on tire width & heigth.Can someone clue me in?
I was led to beleave that the height would be the 1st number & the width is the second number.Others told me just the oppsite.
For example with the first theroy: a 275-50 would be taller & wider than a 255-60.
I just got ahold of some 275-50s (off the rim) & some 255-60s on the rim.
The 50 series are definatily wider than the 60s...But the 50s are 275 & the 60s are taller & yet they are 255s.
Is it because the 60s are on the rim?
Can anyone clue me in?
Thanks...Tom :confused:
 

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The first number represents tread width in mm. So 255 or 275 mm in your example. The second number is section width or essentially sidewall height, as a percentage of your tread width. So a 275/60 has a tread width of 275 mm and a sidewall height of 165 mm (275x60%). Hope that helps some!
 

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Technically: 275/60/15
*275 represents section width in MM - widest part, sidewall to sidewall, not necessarily tread width. That is why some 255s are wider then others. But most view it as tread width.
*60 is sidewall height, as mentioned. (275mm x 0.60)
 

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Tom - hope this ends the confusion. The 255 and 275 are the tires width at the sidewall in metric or millimeters to be exact. (side note : to convert to inches divide by 25.4)

The 50 and 60 are the aspect ratio of the sidewall (height of sidewall) and the number represents the percentage of the tires section width.

That's it...
 

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Edit: wow I'm slow posting :D

http://auto.howstuffworks.com/tire2.htm

The first number (255 or 275) is the actual width of the tire. The second number is the aspect ratio of the tire. Most people confuse this as being the width, but it is actuall what percentage of the first number (width) that the sidewall is high. The 275 is much wider than the 255, so 50% of 275 (137.5) is taller than 60% of 255(153). 153>137.5 - on the same size rim, the 255/60 would be taller, but the 275/50 would be wider. Depending on the first number (width), you can't always say a 50 series would be wider than a 60 series tire.

Second edit, don't forget the rim size is important as well, a 245/75-R16 would be the same height as a 295/45-R20. (see the illustration on the link above)
 

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Discussion Starter #7
WOW!!!
Thanks,that clears it up!
I had no idea there was so many variables,I thought a 50 was always a 50 E.T.C. & it looks like I had everything mixed up!
Thanks for all the help...Tom
 

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a 275/60/15 tire has the same overall diameter as a 235/70/15.
a 255/60/15 tire has the same overall diameter as a 225/70/15- which is also the same as a 225/60/16...

aint numbers fun?
 

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Look into the PLUS-1, -2, -3 and so forth to help you out here at The Tire Rack site!!

And fwiw, the old bias-belted, Sonic Maxima's from back in the early '70's had "square shoulders" so their tread width was about the same width as their section width!!

In other words, an old L-60/15 had about an 11" tread on an 11.5" section width!!

Like real slicks!!

Suckers to this day to me are WAY cool!!

They looked absolutely FANTASTIC on my Buddy's new first year 383/auto/posi "be-beep" Road-Runner!!

pdq67
 

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275/60/15 is 10.82 wide 28" tall.


Take the 275 and divide by 25.4 = ____ ? <---width
then take __above answer__? x .60 = _new answer___? <---aspec (side wall)
then time _new answer____? by 2 = _newer answer____? <--- 2 side walls :)yes: )
__newer answer____? + wheel size = __final answer___? <--- how tall.


These numbers can be used with any tire as long as it's in metric designation, your aspec number will change.
255/50
275/60/15
245/50/16
275/60/16
195/65
245/35/18
Don't matter
 

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Don't always have a computer and a link at hand :D
 
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