tire height

[olebrowndodge]

is there a difference in the height between f-70-15 and f-60-15 ? i know the width is different, and will the f-70-15 clear ok on front a 73 cuda?

 

[Avalanche]

This is a great tool

http://www.rimsntires.com/specspro.jsp

 

[challenger6pak]

The 70 tire is taller and narrower than the 60 tire. Here is a letter chart for the old tires. Go down to the third paragraph.

http://www.pontiacserver.com/tires.html

 

[moparleo]

Yes the F70-15 will fit with no trouble on a 7" rim. The letter series designation went out in the early seventies. Before they used the A,B,C and so on sizing designation, tires were measured by section width and rim diameter. Example 7.75 x 15 would mean that the tire was seven and 3/4" wide at the sidewall section. Not a tread width measurement. So the old "balloon" tires were narrow in the tread contact area but wide in the sidewall. This was before radial tires and the bias ply tires were very stiff in the sidewall causing a rough ride. By making the sidewall larger, it spread out the load over more area cushioning the ride. The current measurements give you the section width(215 mm) x 70( ratio of the tire height to the width, or 70%) -15 ( the rim diameter) or 215/70-15 the first number will always be section width, the second number is called the aspect ratio, or percentage of height to width and the last number is the rim diameter.

 

[Ghoulardi]

TIRE HEIGHT FORMULA

Example: 205/70-15

205 is the width of the tire in millimeters when mounted on the median
recommended rim width and inflated to the recommended pressure.
This may be at the tread or at the sidewall bulge - whatever is the widest
part. This is referred to as the section width.

70 is the aspect ratio which tells you that, in this case, each sidewall is
70% of the width number above. Each sidewall is 70% of 205 mm.

15 of course is the rim diameter in inches.

A 60 is not wider than a 70 but the illusion may be such. Remember the
width is the first number and it is not necessarily measured at the tread.

Here is the formula:

205 (width as measured above) x .70 (the aspect ratio) x 2 (2 sidewalls)
divided by 25.4 (converts to inches) + 15 (the rim size in inches) = the
overall diameter in inches.

If an F series equals a 205 (I'm not sure), here is the comparison:

205 x .70 x 2 = 287 / 25.4 = 11.3" + 15" rim = overall 26.3" diameter

205 x .60 x 2 = 246 / 25.4 = 9.7" + 15" rim = overall 24.7" diameter

If you had the 205/70 on the front you could run a 245/60 on the rear
and maintain the same comparable diameter:

245 x .60 x 2 = 294 / 25.4 = 11.6 + 15" rim = overall 26.6" diameter