Need a little help 59 Fairlane with a Fordomatic . Seem to show about 7 to 8 MPH faster on the speedometer than I am actually going. I have been told that this can be corrected any advise or leads in the right direction would be great.  Thanks Dave

You need to change the nylon/plastic speedo gear that's at the trans at the end of the cable. You remove the cable, then the gear holder. It is pretty ez to get out. My need a small screw driver to start the wedge. Mine was about the same as yours and I added a gear with 2 more teeth and it's now perfect. You need to know what yours is first. Many suppliers have them, I got mine from Macs..good luck

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks so to slow the speedometer down you up the teeth on the gear?

Correct, more teeth on the driven gear means fewer turns on the cable. So, a slower indicated speed. If it's right on, you got lucky. Mine only seem to come close.



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Mechanical speedos were never noted for accuracy. Mine reads 8 mph faster than my actual speed. I just factor that in, keeps me out of trouble...(:> )

I recommend you go one tooth more.  This should make your speedo just a little fast.  As was mentioned above, it might keep you out of trouble with the police.
Pull the speedo cable at the trans, count the teeth on the plastic gear and then get one with more teeth.

Remember that Ford speedo gears point two different ways.  Make sure you get one with the correct orientation.  Ebay has lots of vendors with the gears - that was where I got mine.



54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Not trying to high jack your thread but you guys are already on topic.My 56 f250 is fairly close now but will be swapping out 4.88 for a 3.73 soon.My question is,where are you buying these gears from?Any parts store?Also can a jump this big be made with a gear is my case?
Thanks Dave

I wouldn't be surprised if you can get them at a local parts store.  The Ford drive gear was the same for a long time.
If not, then any place that specializes in classic and vintage Fords, eBay.

In some cases, and I don't know if this is true with Ford, you can only go so far with the speedo drive gear before you have to pull the tailhousing and change the drive gear on the output shaft of the trans.

For really wild gear changes, modern tech comes to the rescue, gps speedometer drives - not cheap, though.




Lawrenceville, GA

Just some background info, there's several of these guys around. The ratio adaptor is what I've used if the gears didn't get me close enough. Not cheap, but probably cheaper than GPS.

http://www.partshp.com/speedometer_gears.htm

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Ebay has loads of these for the 57 and later trans, last time I was looking for one.  Just type in Ford speedometer gear.  I assume you will be able to get your speedo in tune with the new gear, but first you will have to find out how much it's off before trying a new gear.  If you have a up to 56 trans, your not going to find much of a selection.  In 57 Ford changed the design and they won't fit the 56 and under.

Quote: Not trying to high jack your thread but you guys are already on topic.My 56 f250 is fairly close now but will be swapping out 4.88 for a 3.73 soon.My question is,where are you buying these gears from?Any parts store?Also can a jump this big be made with a gear is my case?
Thanks Dave

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ