Dodge RamCharger Central banner

speedometer gear???

4008 Views 7 Replies 6 Participants Last post by  Ram
speedometer gear or whatever it is called that you can change to correct the speedometer after getting different gears. anyway would the dealer have what i need to get my speedometer accurate after going from 235/75/15 tires and 3.55 gears to 33inch tires with 4.56 gears???

thanks for any help
1 - 1 of 8 Posts
Here's the fomula that you requested
first you need to figure the driveshaft rpm at 60
speed x gear ratio x 336 / tire diameter
60 x 4.56 x 336 / 33 = 2786 ( or about )
take that number and devide it by 75
2786 / 75 = 37 tooth gear needed
each tooth on the speedometer gear is equal to about 3 mph.
speedometers cost about $12 at the dealership.
1 - 1 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.