Confirm Correct Speedo Gear

[RedLine]

Love our tire/wheel setup! and we have a new speedo cable! Yeah!    now what gear to use  :dontknow:    hmmmm...

Rear Tires  P275/60R15  on Cragar 15X7's   --  from a chart I got a tire diameter of 27.98, but it seems the tire stands taller squeezed onto the 7" rim.
727 TF    3.23 

It look like my choices are 30 or 31 teeth .    30 for 28.25 and up    31 for  27.75 and below    so would 30 be the best?  Thanks

[heminut]

Redline, what gears are you running in the rear? I have the same size tires and have a 31 tooth speedo gear with my 3.23 rear gears.

[Chryco Psycho]

the tire will not stand taller on the narower rim , the radius from the axle center down is what you are really worried about & the load on the tire wil make the lower radius shorter then the top radius ,
 the 31 tooth will turn the speedo slower so the speedo will read slightly low so you will be speeding slightly compared to the speedo reading , the 30 tooth will be the opposite way & will read s lightly higher than the actual speed , so it really depends which you are more comfortable with , personally I like to have the speedo read a little high so I have some error room

[RedLine]

Thanks CP!  I guess we better go with 30 since I have a leadfoot.   392HN -  its a TF727  with 3.23 on back end.  Thanks for your help.