Thread: Sorry i'm crap at this....

http://www.bfgoodrich.com.au/config/...ensionData.pdf


or


OnlineConversion.com - Tire Size Conversion

So there is about 2" in difference......

Yes Dear - 205/80 are 29's, 235/75 are 30's 245/75 are 31's, 235/85 are 32's and 265/75 are 33's

( 205 wide x 80% tyre wall x 2 + 400( rim size) = diameter

the tread face should be a little over an inch wider and the rolling radius will be maybe an extra inch in the rolling radius of the 245/75's.

First number is the width of the tyre.

Second number is A % height of the sidewall* EDIT

Third number is the rim diameter

These 3 numbers determin the rolling diameter

eg

245/75/16 = 30.6"

245/70/16 = 29.5"

205/80/16 = 28.9"

In percentage terms it is about 6% difference in speedo reading , ie revs at say 100Kmh/pulling power/etc etc.
Regards Philip A

Originally Posted by Redback

First number is the width of the tyre.

Second number is the height of the sidewall

Third number is the rim diameter

These 3 numbers determin the rolling diameter

eg

245/75/16 = 30.6"

245/70/16 = 29.5"

205/80/16 = 28.9"

Sorry, your figures don't add up. The second number is the actually the aspect ratio of sidewall height / width. Low profiles are something 40 (% height / width) and higher profiles are commonly 75 (%).

Have a look here:

Yokohama / UNDERSTANDING YOUR TYRES

cheers, DL

Originally Posted by Redback

First number is the width of the tyre.

Second number is A % height of the sidewall* EDIT depending on profile

Third number is the rim diameter

These 3 numbers determin the rolling diameter

eg

245/75/16 = 30.6"

245/70/16 = 29.5"

205/80/16 = 28.9"

Originally Posted by 350RRC

Sorry, your figures don't add up. The second number is the actually the aspect ratio of sidewall height / width. Low profiles are something 40 (% height / width) and higher profiles are commonly 75 (%).

Have a look here:

Yokohama / UNDERSTANDING YOUR TYRES

cheers, DL

How's that