Question about tires sizes and tread

[Colton92]

I need to get some tires for my rims and have some questions. Does the 45 in 225/45/18 represent the thickness? if so would the higher that number mean longer tread life? How many miles would a 225/45/18 tire on average last? is this a wise choice for a 18 by 8 rim?any input would be great!

[audtatious]

No, the 45 represents the height as a percentage of width.

So, with a 225mm width tire the height of the sidewall is 101.25mm

[rjdmmfl1]

I need to get some tires for my rims and have some questions. Does the 45 in 225/45/18 represent the thickness? if so would the higher that number mean longer tread life? How many miles would a 225/45/18 tire on average last? is this a wise choice for a 18 by 8 rim?any input would be great!

what audatious stated above is correct regarding height of tires... there's a write up of tires in another thread...

http://forums.altimas.org/zerothread/346628

that info was taken from a thread f mine in which I was trying to explain the possible tire/rim combos to stay close to factory specs...

Regarding tread, contrary to what some may tell you, there is no Universal way to determine how long a tire will last The treadwear grade is a comparative rating based on the wear of a tire when tested carefully under controlled conditions. For example the useful tread on a tire graded 400 should last twice as long as a tire graded 200. However, another tire manufacturer may grade a comparable design 300, so a grade of 150 would last just half as long under their grading scheme. The lesson learned is to not use one manufacturer's grade versus the other, but instead to compare tire grades within a given brand. Actual treadwear performance can vary tremendously according to the tire's real-world use. Variations in driving habits, service practices (most importantly air pressure maintenance), road conditions and climate affect tire life.

Hope this answers your question!