Speedometer Drive Gear ratio

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Jan 2, 2024 | 07:12 PM

#16

bmoran4

Parts Nerd Extraordinaire

Joined: Sep 2010

Posts: 4,373

Likes: 1,787

From: Western NY

According to my Ford documentation, your 49 should be using a 8C-17260-A 68" long speedometer cable (casing & shaft assembly) with a 91T-2081 dash clip. I believe the actual shaft length in the cable is 69.23" long. Some of the specialty Ford vendors sell slightly longer cables under that Ford part number which probably work just fine.

Jan 2, 2024 | 08:13 PM

#17

Don T

Mountain Pass

Joined: May 2015

Posts: 105

Likes: 27

From: Lloydminster Ab

For those stuck in this loop of driving/driven speedometer gears there is another option. If you can find a speedometer shop that serviced taxi firms they make a gizmo that fits one end or the other of your speedometer cable that will correct the error. It is mechanical and contains a series of gears which can be manipulated to correct incorrect ratios. I have a 51 M3 that has a new and correct head but I could never find standard parts to make the readings correct. An example would be a optimistic speedometer that is reading high; use your gps to determine the exact amount over, say it is 12%. These people will set up the gizmo to knock the reading down the 12%. The firms I contacted wanted to know all the driveline info to do there settings but if you persist they can work from percentages. If your speedometer and odometer are not correlated you are either get correct miles per hour or correct distance traveled; your choice; not both. Just a alternate to chasing gears.

Jan 2, 2024 | 09:05 PM

#18

mfkgriffin

2nd Gear

Joined: Jan 2024

Posts: 2

Likes: 0

From: West Kelowna, BC Canada

Quote:

Originally Posted by bmoran4

Thanks very much. I have ordered a new one. The one I have is new (previous owner bought it) but the end at the gear side doesn't fit into the gear. I've attached a couple of photos. The cable end is a hex and the gear appears to be round and is smaller in size. Not sure if the cable sitting in there damaged the inside of the gear? I hope not because the obsolete parts web site referenced below indicates out of stock.

Thanks so much for your help.