It means it is a radial tire with 70 aspect ratio.
265 70 R 15
P 265/70 R 15
p205 70 r 15
This tire size fits lots of different vehicles.
standard size: P205 70 r 15
I believe it is P245 / 70 / R 16 - check the information sticker on the end of the drivers door for the original tire size that came on the vehicle
P means passenger tire, 185 is the tread width, 70, or 75 is the aspect ratio of sidewall height to tread width. R is tire bead diameter. Same as wheel size. A 75 sidewall tire is taller than a 70 series.
Read the side of the tire. It should have a number such as 225/70/R15 The 225 is in millimeters, the 70 is a fraction or 70 % of the tread width the R is for Radial tire type and the 15 is the rim diameter. You can also measure the inside of the rim not to include the rim bead. Be sure to tell the rim manufacture the tire size to get a proper fit for the tire width.
Yes, that is a very common change
30 is the diameter of the tire in inches. 950 is the width of the tire which converts to 9.5 inches. R means it is a radial tire. The 15 is the diameter of the wheel.
2008 GMC Sierra ext cab 4x4 has 265 70 r 17
Front tyre 120/70 ZR17MC (58W) Rear tyre 190/50 ZR17MC (73W)