speedo questions

[xplore-this]

i was searchng around and found a speedometer calibrator. now i am plannnin on 35's and 4.56 gears and was considering this but i noticed that it said it was for 92-94 explorers. Now is this a typo or is there a difference in the 90-91 and the 92-94 speedometers in the xplorers.

 

[Robert]

My preference would be to replace the $7.00 speedometer gear. The gear has to be cheaper than the speedometer calibrator.

 

[xplore-this]

the speedo calibrator is about $120 but how much adjustment can you get out of the speedo gear as far as i know you get one with so many more or less teeth but at what point if any does the new gear get too small or too big.

 

[Robert]

Each tooth you go up or down is good for an approximate 5% change. My stock gear had 19 teeth. I have seen Ford part numbers for 16 - 21 teeth. They may go even higher or lower, but I'm not sure. With my stock 19 tooth gear, I could have decreased my tire size by 10 % or increased my tire diameter by 15% which would cover me from a 27" tire up to a 34.5" tire with my stock 4.10 axle. As long as I keep my overall ratio within -10% to +15% of stock through a combination of tires and gears Ford has a gear for me.