Speedometer is off by 15 mph
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 35
Likes: 3
From: Billcity PA
Speedometer is off by 15 mph
So the 77 is on the road and running fine. The speedo is off by about 10 - 15 mph.
it has an orange drive gear on the trans output shaft and a 19 tooth white driven gear on the speedo adapter. I have an extra gray 21 tooth gear. Would that be enough to drop my mph 10 - 15?
it has an orange drive gear on the trans output shaft and a 19 tooth white driven gear on the speedo adapter. I have an extra gray 21 tooth gear. Would that be enough to drop my mph 10 - 15?
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 35
Likes: 3
From: Billcity PA
speedo
I recounted the teeth again and it is 22. I'll give it a shot to see how close we get. Im pretty sure the next gear change would entail replacing the drive gear on the output shaft. Jill may just have live with the results for awhile... Thank you for the info.
Matt
Matt
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
So the 77 is on the road and running fine. The speedo is off by about 10 - 15 mph.
it has an orange drive gear on the trans output shaft and a 19 tooth white driven gear on the speedo adapter. I have an extra gray 21 tooth gear. Would that be enough to drop my mph 10 - 15?
it has an orange drive gear on the trans output shaft and a 19 tooth white driven gear on the speedo adapter. I have an extra gray 21 tooth gear. Would that be enough to drop my mph 10 - 15?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
That's also a possibility. More info is needed on car's history to determine which is more likely. In any event, if the speedo has been 'consistent' for a significant period of time, the issue can either be "corrected" or "masked" by changing the speedo drive gear.
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Thread Starter
Intermediate
Joined: Jan 2018
Posts: 35
Likes: 3
From: Billcity PA
Speedo Fixed
Finally had some time to get the 77 Vette off the ground and change the speedo driven gear. Swapped out the 19 tooth for a 22 tooth gray gear and the speedo dropped about 13 mph. It is very close to where it needs to be so Im going to call it fixed. Thank you to all who offered help, we can all this case closed.
Matt
Matt
