Jeep Speedometer Help!

[Rallydevil]

Ok so i have a 99 wrangler with 35" tires and 3.73 ratio according to my spec sheet. Quadratecs chart calls for a 29 tooth gear so that is what i bought. The one i took out of my jeep was a 30 tooth and i replace it with the 29 tooth and it made no differance at all. Any help would be appreciated.

 

[Bounty__Hunter]

Changing from a 30t to a 29t will make very little change, as you experienced. But is it accurate to your actual speed? Gps verified of course.

 

[Rallydevil]

Changing from a 30t to a 29t will make very little change, as you experienced. But is it accurate to your actual speed? Gps verified of course.

nope 10 to 20mph off. tested with my gps.

Was thinking of getting a higher tooth count but dont know were to start and i dont want to be buying and returning a bunch of gears.

 

[Bounty__Hunter]

It should be within 1-2mph with that gear recommended by all the charts. I would suspect you have a different gear ratio than you think. Check the diff tags and consider pulling the diff covers to check the numbers stamped into the side of the ring gears, verify that gear ratio.