Gears/mileage question

[jermy82]

Got 3.73's in the car yesterday. Feels great of course. But my question is about the speedometer. I know you can buy some different gear to make it read right, but that's extra $ and it doesn't really bother me enough to get it if I don't need it. My question is that does the increased speed that is reading on my speedometer result in more miles being put on the car? I'm not sure if the odometer is dependent on the speedometer or not. I'm sure this is a pretty simple question, but had to ask. Thanks.

 

[Joes95GT]

Yes, the odometer and speedometer are directly related. You are putting more miles on the car than what there actually is.

Joe

 

[mytight95]

yes when i had my 4.10's installed, i waited about three months to fix my speedo, and i racked up about 1500 miles with only around 750 driven, the higher speed you drive the more it is off.


jason

 

[jermy82]

Thanks for the info. Do you know how much the different gear is to make the speedometer read right is? Do I have to go to Ford directly to get it? Thanks again.

 

[blackEagle]

Thanks for the info. Do you know how much the different gear is to make the speedometer read right is? Do I have to go to Ford directly to get it? Thanks again.

You need a 23 tooth gear to fix the speedo. Ford does not make one however, you can get it from the aftermarket(steeda, Holcomb, ect.).

The highest FMS gear is a 21 tooth.

 

[Joes95GT]

To get the speedometer to read right, you can do two things. The first and probably the easiest would be the Dallas Mustang Speedcal. It's a computer type thing that you wire up into the electronics of the car and it compensates for tire size as well as gear ratios. You could also change drive and driven gears. You cannot use the 23 tooth gear and expect it to be right - it will still be off. What you need is a 20 tooth speedometer gear, and a 6 tooth drive gear. The drive gear is in the tailshaft of the transmission.

Joe

 

[randomjoker]

Yeah the drive gears cost some where around $2..

 

[jermy82]

Thanks again for the help. Anybody got a link?