Tires and spedometer

I just swaped the stock tires off my xj for 245/75/r16s' How much is my spedometer off. Is it possible to correct it? I know my charger has a gear that you can swap for the spedometer.

Theres a lil gear in the transfer case.

use this page. it has a chart for tire diameter/gearing and speedo gear, and a chart that converts the metric measurement to imperial (inches).

Anyone know what the rear end options were for a stock 96xj manual 4.0 high output?

3.07

A 245/75/R16 is roughly a 30" tire. Jeeps are notorous for slow reading speedos. The difference between your stock tires, and the new ones plus the inaccurate speedo will probably leave you practually right on, or at leas close enough not to worry about it. I can tell you that mine reads right on running 31"s stock axle gears, and stock speedo gear. I have checked it many times against milage markers, and to the little portable speed checkers that they put out sometimes. On that note my ex's bone stock ZJ read almost 5mph slower than the actual measured speed.

http://www.4lo.com/ see "calculators".

my 94 4.0l HO with auto tranny, original speedo gear and 31's reads 55 mph on the speedo when my GPS shows 62.