Swapped speedometer reads fast
Thread Starter
|
Trailering
Joined: Mar 2024
Posts: 16
Likes: 3
Swapped speedometer reads fast
Hi there. I wanted a tach in my '84 F150 so I bought a gauge cluster that had one. The cluster came with a tripmeter speedo. The tach works great, but the speedo reads at least 10% fast.
I know you normally correct this by changing the speedo driven gear, but this was just a gauge swap. Do different speedometer versions read differently for a given speedo cable RPM? I can put my old speedo back in easily enough but I was happy to have the tripmeter "upgrade."
I know you normally correct this by changing the speedo driven gear, but this was just a gauge swap. Do different speedometer versions read differently for a given speedo cable RPM? I can put my old speedo back in easily enough but I was happy to have the tripmeter "upgrade."
Logistics Pro
Joined: Jun 2017
Posts: 3,981
Likes: 515
From: Edmond, OK
If it's only about 10% off I'd call that good. I know the other gauges in our Bullnose trucks are notoriously inaccurate. I wouldn't think it would be different for the speedometer. Especially if you're testing it with an app on your phone.
Moderator
Joined: Jan 2001
Posts: 56,999
Likes: 2,746
From: Virginia
There is a standard for the speedometer, something like 1000 rotations per mile or something like that. Most likely what happened, someone like me got a hold of it, and moved the calibration. I have done that instead of changing the transmission gear to "calibrate" the speedometer and of course this throws it off the standard. You could try to move it back.
What I did on a older car I had, I figured out how far off the old speedometer was. It was about 10mph off. My wife had a stationary exercise bike that had a speedometer on it. I stuck the car speedometer onto the cable on her bike, and got her to pedal steady, and I just moved the calibration lever till the speedometer moved 10 mph the right direction. I guess you could use a drill set to a steady speed also.
What I did on a older car I had, I figured out how far off the old speedometer was. It was about 10mph off. My wife had a stationary exercise bike that had a speedometer on it. I stuck the car speedometer onto the cable on her bike, and got her to pedal steady, and I just moved the calibration lever till the speedometer moved 10 mph the right direction. I guess you could use a drill set to a steady speed also.
Moderator
Joined: Jan 2001
Posts: 56,999
Likes: 2,746
From: Virginia
Look where the needle pivots. Should be a brass spring down there, and a small lever that puts more or less spring pressure on the needle. But remember this was a older speedometer I was messing with, I have never tried it on anything after the 60's.
FTE Legend
Joined: Nov 2015
Posts: 30,940
Likes: 4,125
From: Angier, NC
Dave ----
Thread Starter
|
Trailering
Joined: Mar 2024
Posts: 16
Likes: 3
Thanks all for the replies. I searched on this problem a lot before posting, but I just found this thread tonight:
https://www.ford-trucks.com/forums/8...f-odo-not.html
Sounds like there is indeed an adjustment for the needle itself. Seems just like my situation and (hopefully) cure.
https://www.ford-trucks.com/forums/8...f-odo-not.html
Sounds like there is indeed an adjustment for the needle itself. Seems just like my situation and (hopefully) cure.
Thread
Thread Starter
Forum
Replies
Last Post
RainyDay
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
5
Oct 3, 2009 04:28 PM
