What speedo gear do I need?

[red85]

I just picked up a nice new to me 96 Ranger Supercab with a 3.0 and an auto. It currently has 14" wheels on it and I hate how they look, I have a nice set of 15" deer hoofs with some fairly agressive 235 75 15's on them. What speedo gear do I need to make sure the speedo is correct? Oh, it has 3.73's in it.

Thanks
Phil

 

[smoke81]

i went from 225/70/14 to 235/75/15 and the speedo was running about 6-7 miles too slow. i pulled out a the 18 tooth gear(which i dont believe comes stock) and by all the math with the helpof the speedo correction sect on the tech page the correct gear size would have been 16 teeth....i went to a 14 tooth gear and now my speedo runs 6-7mi over actual speed(i didthis purposly cuz i get paid by the mile)i really believe the only way to get the change right is to drive thru one of those stationary radar things the cops use or ride next to someone and have them signal u when they hit say 50mph to find out how far off your speedo is then check how many teeth u got now to tell u what u need...each tooth u go less will give u a gain of about 2.5 mph..all the calculators from the tech page work great if u know what you start with is a true reading with stock tires,diff gears,and speedo gear...but i just think the old fashioned way takes all the guess work out :note:the gears are like $2.00 even at the dealer cheap enough to get one of each and throw em in the drawer for future changes

 

[v8318cid]

Check your setup. If you have a mechanical speedo cable, you can change a gear in the transmission. Just look for a thick black cable running down to the side of the transmission case. Look on the tech section for a calculator that can easily figure out what gear to install. However, I believe that the Ranger went to an optical sensor around 95 or so. If that is the case, you'll need to have the dealer (or someone with an OEM diagnostic tool) modify the settings in the ECU to adapt to the new tires/gears.