It's stupid question time!!!

[Chet 02]

Can anybody explain to me exactly what the numbers mean in tire sizing such as 255/70/16?

I got the 16 part...I'm only partially illiterate...lol.



Also, when the offset of a wheel is described, just what does that mean? If it's +25, does that mean there's 25mm to the outside of the vehicle, whereas a negative offset would be further in the wheel wells?



It's hard to believe I've gone this many years without knowing these things because I was too embarassed to ask, but not anymore....I've gotten so used to embarassing myself that it doesn't bother me at all...:wacko: :lol:

 

[Kevin Palmer]

Here is a cut and paste that should help...



TIRE TECH PAGE



Since nobody else will explain tire sizing to you, here it is.....



First number (195 or 205) is the overall width of the tire, not the tread width.



Second number (65 or 60) is the aspect ratio. The sidewall is 60% (or 65% or...) as tall as the tire is wide.



Third number is wheel size.



As a tire gets a lower aspect ratio, the tread gets wider, so a 195/60 will have a wider tread than a 195/70.



Figure out tire diameter as follows:

width * (aspect ratio * 2) / 2540 + wheel size



A 205/60/14 is only about 1% shorter than a 195/65/14 but will have a wider tread width.

 

[Ben Poche]

255 is 255 milimeters wide 70 is 70% of 255= side well height

 

[TRACket Paul]

Another source:

 

[Chet 02]

Excellent...thanx Coastie. It actually makes sence to me for the first time.



Anybody got anything of the offset question....and while I'm at it, what is the factory offset for a Trac with 16" factory wheels? I know I could do a search but, being at work, they think I should be using the computer to monitor reactor parameters...lol (It's only a nuclear reactor...lol)

 

[Chet 02]

Oops....I was typing while you were sending Paul...thanx for the info.

 

[EddieS'04]

The factory wheel is 16x7, with a +12mm offset....

 

[Chet 02]

Great...thanx Eddie.