# Speedometer Gear



## Danny Goat (Dec 9, 2020)

Can I change the gear on the speedometer cable? It's a 4 speed; or does the clock needs recalibrated? I changed the tires to smaller ones, and it's off about 5-7 mph faster at the same rpm. Thanks


----------



## Old Man Taylor (May 9, 2011)

They make different driven gears that are easy to change.


----------



## GTOTIGR (May 3, 2020)

The enclosed article states that if your speedometer is fast that you need more teeth on your driven speedometer gear to slow it down.








Speedometer gear change (up teeth or down)?


Ok guys I have a sbc 350 with a powerglide and 3:73 gears and mt speedometer is funning high by 8-10 mph . Do I get a gear with more teeth or less...




www.jalopyjournal.com





As OMT states they are easy to change. You can buy them reasonably priced in packages containing a selection of tooth count.


----------



## Danny Goat (Dec 9, 2020)

My tire size is 245/60R14, and the rear end gear is 3.73. Any ideas which gear to buy? The original rear end was 3.55. Thanks.


----------



## GTOTIGR (May 3, 2020)

Danny Goat said:


> My tire size is 245/60R14, and the rear end gear is 3.73. Any ideas which gear to buy? The original rear end was 3.55. Thanks.


Hi, my suggestion and non-scientific approach that I took was to remove the bullet with the speedometer driven gear in it, count the teeth and purchase gears up and down from that tooth number. There are variables such as drive gear tooth count, amongst others, that come into play if you attempt to calculate the specific drive/ driven gear requirements.


----------



## Danny Goat (Dec 9, 2020)

Where can I order a package of speedometer gears for a Muncie M20 4 Spd? Thanks


----------



## Old Man Taylor (May 9, 2011)

This is one place you can try. Just do a Google search for more options.

Speedometer Driven Gears


----------



## Danny Goat (Dec 9, 2020)

Thanks


----------



## rockdoc (Mar 16, 2009)

Danny, you should be able to use one of the calculators online to get very close. The gears are color coded, so you "may" be able to tell what you have when you remove yours. I say "may" because they are often discolored by the transmission fluid. Wallace Racing has a nice discussion here: Speedo Gear Calculator - Wallace Racing.
I purchased mine at AmericanHotRodSolutions.com, but you can find gears in many places. Don't forget that you can only go so far with a new gear and then will have to get a different sleeve. Kerry at American Hot Rod Solutions was a big help in fixing mine, and my speedo is now right on.


----------



## Danny Goat (Dec 9, 2020)

Thanks so much for everybody's help.


----------

