#59890

Though not listed in 15 tooth version, most Mustang parts houses have speedo gears starting at 16 teeth and going to 20 teeth. They also have speedo drive gears in 6,7,& 8 tooth versions. There is also a formula for calculating the correct gear depending on drive gear teeth, axle ratio, & tire revs per mile:

driven gear teeth = drive gear teeth x axle ratio x rev per mile divided by 1000

Hope this helps.

Fred Baum