The Ford Barn

len · 08-11-2013, 07:36 PM

Can anyone tell me the correct Speedo gear for a stock 1956 with a three speed and OD. Thanks

Blue Futura · 08-12-2013, 06:22 AM

It depends on the tire size and rear gear ratio . My 56 has a 3.89 rear gear, most overdrive ones came with that. I think it is 21 but i haven't had it out for about 14 years.

You can go to www.gtsparkplugs.com and use their calculator . Click on " Automotive Calculators " then on "Speedometer Gear Size " .There are others online but theirs looked pretty easy to use. There is a drive gear and a driven gear in your transmission . Most of the time you are just needing the driven gear which can range from 16 to 22 , i'm guessing 21 or 22 , depending on what your rear gear and tire size is.___JIM__

zoegrant · 08-22-2013, 09:08 PM

Len ,my 56 t-bird 3 speed with overdrive and rear axle ratio of 3:31 uses a 22 teeth speedo gear...my car was an automatic which I converted to standard...J

miker98038 · 08-22-2013, 10:36 PM

Go over to the aaca site, there was just a discussion on this. I don't think any o/d car ever had a 3.31 so you might need an aftermarket gear adaptor.

http://forums.aaca.org/f225/56-t-bir...ns-356747.html

Blue Futura · 08-23-2013, 06:15 AM

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The o.p. "Len" has not told us what gear ratio his car has and with out that information we can't give him much help. 1956 ford passenger cars with overdrive came with a 3.89 rear gear , at least all three i have owned did. But it may have been changed or somebody may have put the overdrive in an auto trany car with out changing the rear gear. I could crawl under my 56 and remove the gear to see what it is but it's in storage now and kinda hard to get to.

08-11-2013, 07:36 PM	#1
len Member Join Date: May 2010 Posts: 75	speedo gear No of teeth Can anyone tell me the correct Speedo gear for a stock 1956 with a three speed and OD. Thanks

08-12-2013, 06:22 AM	#2
Blue Futura Member Join Date: Jul 2013 Location: South west Idaho Posts: 45	Re: speedo gear No of teeth It depends on the tire size and rear gear ratio . My 56 has a 3.89 rear gear, most overdrive ones came with that. I think it is 21 but i haven't had it out for about 14 years. You can go to www.gtsparkplugs.com and use their calculator . Click on " Automotive Calculators " then on "Speedometer Gear Size " .There are others online but theirs looked pretty easy to use. There is a drive gear and a driven gear in your transmission . Most of the time you are just needing the driven gear which can range from 16 to 22 , i'm guessing 21 or 22 , depending on what your rear gear and tire size is.___JIM__ __________________ 64 Futura , bought new. 56 ford fairlane , bought about 30 years ago. 35 chevy street rod , started building in 2000. Last edited by Blue Futura; 08-12-2013 at 06:28 AM.

08-22-2013, 09:08 PM	#3
zoegrant Senior Member Join Date: Jun 2010 Location: tolland CT Posts: 773	Re: speedo gear No of teeth Len ,my 56 t-bird 3 speed with overdrive and rear axle ratio of 3:31 uses a 22 teeth speedo gear...my car was an automatic which I converted to standard...J

08-22-2013, 10:36 PM	#4
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,398	Re: speedo gear No of teeth Go over to the aaca site, there was just a discussion on this. I don't think any o/d car ever had a 3.31 so you might need an aftermarket gear adaptor. http://forums.aaca.org/f225/56-t-bir...ns-356747.html

08-23-2013, 06:15 AM	#5
Blue Futura Member Join Date: Jul 2013 Location: South west Idaho Posts: 45	Re: speedo gear No of teeth Sponsored Links (Register now to hide all advertisements) The o.p. "Len" has not told us what gear ratio his car has and with out that information we can't give him much help. 1956 ford passenger cars with overdrive came with a 3.89 rear gear , at least all three i have owned did. But it may have been changed or somebody may have put the overdrive in an auto trany car with out changing the rear gear. I could crawl under my 56 and remove the gear to see what it is but it's in storage now and kinda hard to get to. __________________ 64 Futura , bought new. 56 ford fairlane , bought about 30 years ago. 35 chevy street rod , started building in 2000.