calculating tire sidewall

[Alex29573]

if i have 305/45/22 then that would mean that profile/chunk/sidewall of my tire should measure 305 X .45 = 137.25mm (5.4 inches)

how come my tires dont measure that much? what am i doing wrong??

 

[JKmotorsports]

You calculated correctly. That measurement (section height) also includes the tire bead, the portion of the tire that mounts inside the rim. Plus the weight of the truck squishes sidewall height down some.

 

[Alex29573]

so if i get a tire that i calculate to be 9mm less would it make sense to measure 9mm off my tire.....or would this new tire have less section height/tire bead going inside the rim??

thanks!

---------- Post added at 10:57 AM ---------- Previous post was at 10:54 AM ----------

oh and to take care of the truck's weight squishing the sidewall can i just measure the top half of the tire??