question about speedo driven gears
Thread Starter
4th Gear
Joined: Apr 2017
Posts: 4
Likes: 0
question about speedo driven gears
I have a 1978 vette that I recently purchased. The speedo is about 10 miles per hour slow. My tire size is 255/60/15s and my rear gear ratio is supposed to be 3.73. What spedo gear would I need to correct the speedometer?
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 330
From: Indy Indiana
if your speedo is too slow, then the cable is spinning too slow, you need to speed it up by replacing your driven gear in your transmission by a smaller one, one with less teeth. pull out your original from your tranny.
they are pretty cheap. you can buy them from parts vendors..get 2, one with 1 less teeth, and the second with 2 less teeth... then trial and error using your phone's gps speedometer app.
this is what they look like:
http://www.ebay.com/itm/like/1520521...&ul_noapp=true
they are pretty cheap. you can buy them from parts vendors..get 2, one with 1 less teeth, and the second with 2 less teeth... then trial and error using your phone's gps speedometer app.
this is what they look like:
http://www.ebay.com/itm/like/1520521...&ul_noapp=true
Last edited by joewill; Apr 4, 2017 at 12:57 PM.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,573
Likes: 7,016
From: New Or-leens Loo-z-anna
Also try to SEE the color of the drive gear that is inside your transmission. The drive gear and driven gear need to correspond in the chart to prevent damaging each other.
Last edited by doorgunner; Apr 3, 2017 at 08:27 PM.
Thread Starter
4th Gear
Joined: Apr 2017
Posts: 4
Likes: 0
speedo gears
is your speedo is too slow, then the cable is spinnging too slow, you need to speed it up by replacing your driven gear in your transmission by a smaller one, one with less teeth. pull out your original from your tranny.
they are pretty cheap. you can buy them from parts vendors..get 2, one with 1 less teeth, and the second with 2 less teeth... then trial and error using your phone's gps speedometer app.
this is what they look like:
http://www.ebay.com/itm/like/1520521...&ul_noapp=true
they are pretty cheap. you can buy them from parts vendors..get 2, one with 1 less teeth, and the second with 2 less teeth... then trial and error using your phone's gps speedometer app.
this is what they look like:
http://www.ebay.com/itm/like/1520521...&ul_noapp=true
Thanks
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