Dumb Tire Question
Senior User
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From: California
check out - http://www.procomptires.com/conversionchart.htmthat way you can compare the sizes to the metric sizes
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From: Milky Way Galaxy
Just to be clear the 12.5" in 33"x12.5" is not the tread width. It's actually the section width/cross section. This is the widest point on the tire which is the sidewall bulge and can vary depending on what rim width your using. It's good to know in case you measure the tread width and start to get upset that the tire manufacturer lied to you about how wide their tires are.
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From: California
Originally Posted by EnviroCon
Just to be clear the 12.5" in 33"x12.5" is not the tread width. It's actually the section width/cross section. This is the widest point on the tire which is the sidewall bulge and can vary depending on what rim width your using. It's good to know in case you measure the tread width and start to get upset that the tire manufacturer lied to you about how wide their tires are.
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Originally Posted by mikedeason
So why not use width (tire width in mm)/ Aspect Ratio like the others ?
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From: Milky Way Galaxy
Originally Posted by dscofever
See...your teacher was right...there are no dumb questions. Just dumb people like me giving you the wrong answer
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From: South Texas
Originally Posted by EnviroCon
You're looking at it from the wrong point of view. It's not a dumb person giving a wrong answer, it's one member who's got the back of another member in case they oops.
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From: Southeast GA
Good question but you got one wrong answer. 33 is the heighth. 12.5 is the tread width, NOT the section width as stated and the 17 is the rim diameter.
The section width is variable, according to the rim width you are using and if it's listed in a tire's specs, it will designate a certain section width when measured with a certain rim width.
The tread width is a constant width, irregardless of the rim width.
The section width is variable, according to the rim width you are using and if it's listed in a tire's specs, it will designate a certain section width when measured with a certain rim width.
The tread width is a constant width, irregardless of the rim width.
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From: Milky Way Galaxy
Originally Posted by hotrodford87
Good question but you got one wrong answer. 33 is the heighth. 12.5 is the tread width, NOT the section width as stated and the 17 is the rim diameter.
The section width is variable, according to the rim width you are using and if it's listed in a tire's specs, it will designate a certain section width when measured with a certain rim width.
The tread width is a constant width, irregardless of the rim width.
The section width is variable, according to the rim width you are using and if it's listed in a tire's specs, it will designate a certain section width when measured with a certain rim width.
The tread width is a constant width, irregardless of the rim width.
Last edited by EnviroCon; Feb 14, 2006 at 10:52 PM.
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From: Southeast GA
Thats's industry standard. Now if you're talking about 50 series tires or 60 series etc, that is a percentage of the tires height. Section width, as you stated the 12.50 indicated, is not mentioned in the size nomenclature.
For instance, I drag race. I run a 29x12.0-15 slick on my truck. A Hoosier slick in that size will fit under my fenderwell...they have something like a 13.3" section width. However, a Mickey Thompson 29x12.0-15 scrubs my fenderwell. That's because the section width is about 13.6. i.e. the sidewall bulges out more, even on the same width rim. Furthermore, if you measure the tread width (the 12.0 part) they are both 12" wide when measured at the tread width.
k?
For instance, I drag race. I run a 29x12.0-15 slick on my truck. A Hoosier slick in that size will fit under my fenderwell...they have something like a 13.3" section width. However, a Mickey Thompson 29x12.0-15 scrubs my fenderwell. That's because the section width is about 13.6. i.e. the sidewall bulges out more, even on the same width rim. Furthermore, if you measure the tread width (the 12.0 part) they are both 12" wide when measured at the tread width.
k?
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From: Milky Way Galaxy
Originally Posted by hotrodford87
Thats's industry standard.
Yokohama
Tire Safety
Tyres International
If that's not enough check the specification sheet from a manufacturer of LT tires. You'll notice that the section width or cross section numbers listed for the flotation sized tires match up pretty closely with the number given for width in the advertised size. I don't know how drag racing slicks are sized, but I do know how LT tires are.
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From: Southeast GA
You use your measuring stick and I'll use mine. There's no use beating a dead horse here but I assure you that a 33x12.50-15 has a TREAD width of 12.5". The section width can vary by as much as an inch between brands. The same holds true for LT235/75R16 tires which I run on about 5 different trucks and 6-8 trailers (that would be about 70 tires of this ONE size if you're counting). Some of them when mounted in pairs, like on a dually, will have 2" between the sidewalls. Others will nearly rub. They are all 75 series tires but different manufacturers have different section widths. The same is true for your 33x12.50-15.
'nuf said...
'nuf said...
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From: Milky Way Galaxy
Well folks, there you have it. 2 opposing answers as to what the 2nd set of numbers in a Flotation/Numeric sized LT tire means. Tread width or Section/cross section width.
One answer is supported using references from well known names in the industry, as well as, an easy way to determine for yourself by looking at a manufacturers LT tire spec sheet and seeing where you believe they got the second set of numbers from. Or better yet, if you have Flotation/Numeric sized tires, go out and measure the tread and then measure from the inner sidewall to the outer sidewall and see which one comes the closest to the size listed on the tire.
The other answer is unsupported and therefore just an opinion, based on their own beliefs and the fact that they use LT tires on their vehicles.
You choose who to believe.
One answer is supported using references from well known names in the industry, as well as, an easy way to determine for yourself by looking at a manufacturers LT tire spec sheet and seeing where you believe they got the second set of numbers from. Or better yet, if you have Flotation/Numeric sized tires, go out and measure the tread and then measure from the inner sidewall to the outer sidewall and see which one comes the closest to the size listed on the tire.
The other answer is unsupported and therefore just an opinion, based on their own beliefs and the fact that they use LT tires on their vehicles.
You choose who to believe.