Originally Posted by jfoster5150
Hi fellas got a question about speedo ratio building a shovel "82" putting it on a 74 frame not sure of the year of the tranny other than a four speed box it has a 23 tooth speedo drive gear does that go to a 1:1 or 2:1 speedo I think its a 1:1 but would like some other opinions...Thanks Jim
Miles T.G. is correct regarding the front wheel driven speedometers with a 19" wheel. That's what I have on my 1982 FXS and the speedometer is a 2:1. This is marked on the back of the speedometer, near the cable thread. Usually this will be a 5/8-18 U.S. thread.
I took a look in my CCI catalog, section 16 where they keep the tin parts and speedometers and such. They state the following:
2:1 Ratio Speedometers: Fit FL models with transmission-driven speedometer drives from 1947 through 1967 and Sportster, FX and FXR models with front wheel speedometer drives from 1973 through 1990 except softail and 4 speed FXWG models. (5/8-18 nut on cable)
1:1 Ratio Speedometers: Fit 4 speed FL and FX models with transmission-driven speedometers from 1968 through 1983/ (5/8-18 nut on cable)
2240:60 Ratio Speedometers: Fit all softail and 4 speed FXWG models from 1984 through 1990 and 4 speed FL models with front wheel speedometer drives from 1981 through 1984. (Requires speedometer cable with 12mm nut)
So, it looks like you would use 2:1 for an early 4 speed and 1:1 for a late 4 speed.
Where it really gets strange is CCI only shows one transmission drive gear unit and that has a 23 tooth gear and it's listed for all of the transmission-driven models I mentioned above. That's likey because the gears inside that drive the outpout gear are different sizes for the different years mentioned.
My take on it would be that the 2:1 is most common and it would probably be the most likely candidate. Hope it works for you.