Decoding Numeric Tire Labels.

[O'Rattlecan]

Okay, help me out folks. I'm confused as heck. I thought I had it, but found an online tire size checker and it totally threw what I knew out the window.

Say I have a 235/75/R15 setup.

First number stands for what?
Second number stands for what?
Third number stands for wheel radius.

Help me out folks. I'm going to be buying some tires in the near future and would like a tire that's about an inch or two taller and a hair wider.

Ryan

 

[6L PWR]

RYAN!! I'm so ashamed of you!! Look at your sponsors site for the answers:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=46

 

[O'Rattlecan]

Thanks.

First number designates width of tire
Second number designates percentage*sidewall width = sidewall height.
Third number designates wheel diameter.

Ryan

 

[surewhynot]

I liked 255/70 r 15's when I had my 95 2wd

 

[O'Rattlecan]

I was liking the size of 265/75/15

Would this cause any problems? My wheel wide enough? The tire height is exactly what I was hoping for. A hair UNDER 31".

Ryan

 

[Rusty Shackleford]

try www.powerdog.com

 

[A_G]

the first set of numbers is a measurment in some kind of form (prolly centimeter) for the height. the second set of numbers is the percentage of that first measurment Or sometimes a ratio, that equals with. And then the 3rd set is the size of the wheel.

No somtimes say a

255/65/15 and 255/65/16 will not be the same width and hieght.

If your converting from a 255/65/15 to a 16 inch wheel and you want the same height or with. You rneed to go up to a 255/70/16.

the first set of numbers can range anywhere from (for car tire/truck tires)
can range form 195-305

The second set of numbers ive Seen range from 50-95.
3rd set ive seen some huge ones up to 26s for car tires.

then you have LT(light truck) series tire and the P (passenger). Which will read for say LT235/75/16 or a P235/25/16 A set of numbers with out the letter before it are almost always reverting back to a Passenger style tire.

A passenger style tire is a little more flexible and grips well. The side walls wont be stiff. They range from a 4-6 ply tire. It will keep your ride quality. A lt and a p style tire of the same measurments the p tire will look fatter while its dismount as it slouches under its own weight.

A LT style tire has heavy duty sidewalls. Most found on Heavy pickup trucks. and dauls. There 4-10 ply. There reall sollid tires. There made for hauling heavy loads. And most require a higher tire pressure than the P style tires. Most around 65-85 psi. depending on vehicle.

now the other measured tires are

for say

30x9.50x15
30 inches tall, by 9.5 inches wide and a 15 inch rim.there simple.

On the LT And P thing they can also be marked as either after the rim size.


Anthony

I work at a tire shop.
Clydes tire and muffler
In tahlequah ok.

Theres semi truck tires too.

 

[A_G]

I was liking the size of 265/75/15

Would this cause any problems? My wheel wide enough? The tire height is exactly what I was hoping for. A hair UNDER 31".

Ryan

yes your wheel will be wide enough. I believe that is what my dad is running on his 97 f150. when you get to the 85-95 mark it becomes a pain in the butt. The bead will rip very easily at those sizes.

a 295-95-15 is a 10 inch wheel sized tire.

 

[fatherdoug]

I love these tire measurements! millimeters to % to inches. Are they smarter than a fifth grader???

 

[mtflat]

It makes a little more sense than the old system..... exactly how and why did they come up with G78-15?

A_G, I don't understand why the bead rips on 85 or 95 series tires? Seems to me the height of the sidewall would make them easier to mount.

btw I run AVON LT215/85R/16's on my 48 F1. Similar to the stock profile but track better and are tough as nails.

 

[DOHCmarauder]

Sorry for ressurecting an old thread, but I needed to correct something.

the first set of numbers is a measurment in some kind of form (prolly centimeter) for the height.

Negative. The 1st numbers is width in millemeters.

the second set of numbers is the percentage of that first measurment Or sometimes a ratio, that equals with. And then the 3rd set is the size of the wheel.

No somtimes say a

255/65/15 and 255/65/16 will not be the same width and hieght.

1/2 correct...............the width would certainly be the same at 255.

The height of the tire would be different only by the size of the rim since both tires would have the exact width and sidewall ratio.

If your converting from a 255/65/15 to a 16 inch wheel and you want the same height or with. You rneed to go up to a 255/70/16.

Negative again......the 1st tire would have a total side wall height of 13" (255X.65 X 2). Add the rim size and you're at 28".

The 2nd tire would be at 30" tall.

the first set of numbers can range anywhere from (for car tire/truck tires)
can range form 195-305

Much larger range than that......

Anthony

I work at a tire shop.
Clydes tire and muffler
In tahlequah ok.

Theres semi truck tires too.

 

[CaFordDude]

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