How wide is a 225 tire?
 

On the left, a set of 225/50/15 tires mounted on 7" Cookie Cutters.

On the right, another set of 225/50/15 tires mounted on 7" Cookie Cutters.

[img]http://forums.pelicanparts.com/uploads9/Porsche+9441162508139.jpg[/img]

The width is I believe trad width, not tire width overall, the set on the left has practicly no sidewall bulge, and the tread ends with the edge of the tire, whereas the tire on the right has a "shoulder" , making it wider. try line it up flat to flat, and see if its about the same.

The 225 is supposed to be the max width of the tire, from bulge to bulge in millimeters.

Hoosiers are notorious for being wider than just about anybody else.

If the class rules limit tire width, the Hoosiers offer an advantage.

The 225 indicates this tire is 225 millimeters across from the widest point of its outer sidewall to the widest point of its inner sidewall when mounted and measured on a specified width wheel.
It looks like you have two different brands there... maybe the manufacturers used different width rims as their basis for the measurement.

Yup. Yokohama 032R, and Hoosier A3SO4. They're what I use when racing my 944. Yokos when wet, Hoosiers when dry.

THere are two relavent width measurements for tires...

The SECTION width defines the wider part of the tire, at the sidewall bulge (if there is one) and the TREAD width that defines what touches the road. A 225 tire is supposedly 225mm across in section width. (ie 8.86 inches. Now depending on the tire mfg. that can be more or less than the actual tread width.

As stated above a Hoosier Radial is typically an inch more more WIDER tread width than section with. Many low profile street tires are like this. A Hoosier bias ply is just the opposite, with a section width nearly an inch or two wider than the tread.

tread width can vary from manufacturer to manufacturer for the same "size" tire.

Theoretically, a 225/50/15 means the following: 225mm wide X 50% side wall profile = 112.5 mm distance from edge of 15" wheel to surface of tire. So 112.5mm/25.4= 4.43" 4.43"x2=8.86" 8.86" + 15" wheel size= 23.86" overall tire diameter.

A 225/60/15 using the above formula calculates to 25.63" diameter.

Just in case anyone did not know how the rest of the numbers worked into tire size calculations.

Tim,
No expert but I thought an inch was 25.2mm not 25.4mm. If so, it changes your calc's.

25.4 is right

That must be why all the machinery I design that uses metric components never fits right :D

25.4 is correct. (If not, I am going to shoot myself :D )

2.54 cm per inch. 25.4 mm per inch. Right on.

I've seen supposedly same "size" width tires by the same manufacturer (different lines) look visually different when placed next to one another like that. It's like "S, M, L, XL" sizes on shirts - it doesn't mean squat. Heck, even supposedly accurate sizes for things like shoes or womens' clothing vary wildly depending on the specifics of who takes the measurements, exactly where, etc. I've gone shopping for jeans and had everything from a 32x32 to a 36x36 fit me the same way. . .

Just to add to your confusion, not only do different manufacturers make nominally 225 in &#177 sizes. They all use different shoulder designs, anywhere from square to rounded and the same 225 on an 8" wheel will be ~.4" wider than when it is mounted on a 7

They can put the wrong label on jeans. Not as easy to do with a tire that is molded.