What size speedometer gear

I've searched, but still want to ask what size gear I need. 354 gears with 225-70-15 tire. Thanks Terry

I measured my exact dia with rollout then went to the chart in the archives & it just needs that dia & the gear ratio & the pinionteeth number it stated was a dead on match on the last one I did. It will get your ODO correct(ed) & if the speedo magnetic gismo is calibrated correctly then you're set & most of the time once you get the ODO corrected with the right tooth pinion then the speedo comes in dead on also. if the speedo is off then the speedo head needs to come out & be sent to a speedometer specialty calibration shop to be worked on. Someone posted another chart with tire dia's in the tenths such as 26.1 & it might be in the archives now or someone might be kind enough to (re)post it. Other than GPS, the roadside portable MPH lit up digital signs are the most accurate for MPH (approach it at a steady speed with no nearby vehicles) and going 5 miles on the interstate to see if 5 mile markers on the side of the road is 5 miles on your ODO is the best way to see if you have the right pinion for your gear ratio/rear tire dia

Also, each tooth on the gear is worth apx 2 MPH. The odometer is gear driven while the sped is with magnets.

since your tire is 27.4 tall a 34 should be right.

http://tire-size-conversion.com/tire-size-calculator/

Thanks everyone. I was going to get the 36 until I found another post with the 34. Will measure tires when I get time. Funny, I want to put a 4 speed in my car some day. I have 2 18 spline trans. Went to rob speedo gear from one to put in the other. Neither had a gear.