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Mechanical drive Speedometer

Started by dubepj, April 14, 2021, 05:55:05 AM

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dubepj

Have an aftermarket Speedo that was on a 1985 FXWG.  Mechanical drive from the front wheel, Sold the bike. ( I know Kicking my butt).  Now i have a 1995 FLSTC also with mechanical drive.  Is the speed ratio the same???  Or should I try to sell this one.  This is in KMPH (Metric) and says 1400 RPM = 60 KMPH.  Thanks

JW113

The FXWG had a 21" front wheel, the FLSC has a 16" from wheel. The 21" turns fewer rotations per mile than the 16". The other thing to consider is that the speed drive also does duty as the left side wheel spacer, and the spacers between FXWG wheel and FXST are different. So, no, you can't use it on the softail.

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-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

xlfan

The speedometer ratio is actually the same for -85 FXWG and -95 FLSTC, the ratio and spacer difference lies in the speedo drive. You will loose the reed switch that activates the -95's turn signal canceller ability though.

1400 RPM = 60 KMPH, you are sure that speedometer showed correct speed on the -85?

JW113

As I understand it, the 1.275" drive ratio is for the 16" tires, and 1.3:1 ratio for the 21" tires.

The speedos themselves are 2240 rpm (of the drive cable) = 60mph. Since the 21" tire turns fewer times per mile than the 16", the 21" needs a slightly higher speedo drive ratio to turn the cable faster.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber