Let's say this is the reading off the side of a tire (just taken from the internet)

P225/50R16

from that how do you tell the tire "size". Related, when one refers to a tire as 31 inches, what part of the tire is the measurement based on? From rim to tread?

thanks

As I understand it, a 31 inch tire is 31 inches tall. so if it is mounted on your vehicle it would be 31 inches from the ground to the top of the tire.

For the tire size you list, it is a bit different. P225/50R16 means the following:
225 is the width of the tire (cross section) in millimeters.
50 refers to the sidewall (from rim to tread) and indicates that it is 50% of the cross section width.
16 is the wheel diameter

you're talking about metric size vs standard size


when you got like 265/75/16 or whatever, thats a metric size

31, 32, 33 inches thats a standard (US) size (tire height)

you can use the following tire calculator to covert one into the other

http://www.4lo.com/calc/gearmetric.htm

225/50/16 is a 24.9" tire. Thats like a small car tire. I sure hope you dont have that mounted on a pathfinder LOL !!!

Just checked and I have 27.5" on right now ha. 31" BFG A/T's will fit with no rub for sure?

I believe the maximum tire size on the 01-05 Pathfinder is about 255/70/16 without rubbing anything. This is approximately 30".

As an aside, you should consider that if you put on a 31" tire, your rotors will now make less rotations per minute to travel the same distance as stock tires. If you have an automatic transmission, this will affect the gear positions where the transmission may stay on an inappropriate gear too long, or may switch between gears more frequently at certain speeds... which by the way will also be inaccurate because your speedometer will show a slower reading, your odometer will count slower, torque and fuel economy will decrease on stop and go traffic. These can all be fixed though by re-gearing your computer.

But that won't happen at 30"?

For an 04 Pathfinder SE, the tire size is P255/65/R16. This is about 29" tall. For a 30" it will still happen but marginally.

woops that is the tire size, I typed 225 into the conversion calculator on accident. What sort of tires have you guys put on that have a more aggressive tread?

I have a set of Kuhmo Road Venture M/T's that I use for the winter. The size is 245/75/16. You can't get much more aggressive then theses.

Yeah ive noticed with my 20;s now the gear shifts do feel and sound different, and the rpm;s are a bit off too, and the speedo reads 2 mph-3mph slow, meaning at 60 im going 58ish, with my snow tires i think it was 3mph usually but 2 also.

iPath wrote:woops that is the tire size, I typed 225 into the conversion calculator on accident. What sort of tires have you guys put on that have a more aggressive tread?

Look for an All Terrain tire. It'll usually be advertised as 'A/T'.
They'll look a lot more aggressive and have a stiffer sidewall than an All season tire. I run the Hercules Terra Trac A/T's that came on my Pathfinder when I bought it and run General Grabber AT2's on my Jeep. They both do really well in deep snow.
You could also run a Mud terrain tire or MT, but they aren't very good in sand.

Hercules Terra Trac AT's


General Grabber AT2's