Tire Size Calculator

[theMerchant]

Another useful tool I have been using and want to share.

You can plug in your original tire size and compare the circumference to the new tire.:top:

http://www.miata.net/garage/tirecalc.html

 

[rookie]

offset calculator
http://www.1010tires.com/WheelOffsetCalculator.asp

wheel offset and tire size calculator
http://www.wheelsmaster.com/rt_specs.jsp

 

[EG3]

another tire size calculator. Allows you to compare between different sizes:
http://www.1010tires.com/TireSizeCalculator.asp

 

[EG3]

offset calculator
http://www.1010tires.com/WheelOffsetCalculator.asp

wheel offset and tire size calculator
http://www.wheelsmaster.com/rt_specs.jsp

Have a question here. These are the two results for same comparison on offsets and clearance:
from wheelsmaster:
Wheels:
Wheel sizes: 20x8 ET 40, 20x10 ET 42
BackSpace:154 mm (6''), 181 mm (7.1'')
27 mm (1.1'') deeper.
Rim Lip
23 mm (0.9'') wider

from 1010tires:
Inner clearance: 27mm LESS
Outer position: EXTEND extra 23mm

What's the problem here? In the first one, it says it's 27mm deeper, in the second one it says 27mm narrower??? This wheel is a lipless one so the offset type will be positive I believe. Does the 1010tires calculator calculates the negative offset and the wheelsmaster calculates the positive? Is that the problem?

 

[rookie]

Kinda lost me

Backspacing is not calculated on the 1010 tire one.

Both say the same thing 23mm out further from the hub, 27mm less inner clearance from the hub.

The wheel you entered is 10" wide +42. your offset is 2mm less than the 8" wide +40. the 10" wheel puts an inch in either direction since offset is based on wheel width.