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Stevoone · 03-24-2010, 09:43 PM

I'm not positive about having to change them when swaping a speedometer.

Edit: I misunderstood the operation of a mechanical speedometer so I look around on google. There are more detailed articles but this was the first one I saw http://www.explainthatstuff.com/how-...ter-works.html

I looked around online again and found that it may be necessary to change the gears depending on the speedometer. You would have to look at stampings on the speedometer to see how many revs per mile it needs to read properly. It also says that most car manufactures used the same rev/mile for most of their cars. So you may not have to change them for the swap that you are doing.

I would install the new speedometer and see how it works. If the MPH is off then you would need to go after gears. If it reads correctly then nothing else need to be done.

03-24-2010, 09:43 PM	#9
Stevoone Join Date: Mar 2007 Location: NJ Posts: 540 iTrader: (2)	I'm not positive about having to change them when swaping a speedometer. Edit: I misunderstood the operation of a mechanical speedometer so I look around on google. There are more detailed articles but this was the first one I saw http://www.explainthatstuff.com/how-...ter-works.html I looked around online again and found that it may be necessary to change the gears depending on the speedometer. You would have to look at stampings on the speedometer to see how many revs per mile it needs to read properly. It also says that most car manufactures used the same rev/mile for most of their cars. So you may not have to change them for the swap that you are doing. I would install the new speedometer and see how it works. If the MPH is off then you would need to go after gears. If it reads correctly then nothing else need to be done. Last edited by Stevoone; 03-25-2010 at 07:20 AM.