Crazy speedometer

[73c20jim]

How can a mechanical speedometer be 10 MPH slow and the next day be almost dead on. GPS check.

 

[Matt69olds]

I’m guessing either the gears inside the speedo are dry (grease dried out?) more friction, spins slower, or maybe temperature related? Cold speedo lube, more friction?

 

[73c20jim]

I’m guessing either the gears inside the speedo are dry (grease dried out?) more friction, spins slower, or maybe temperature related? Cold speedo lube, more friction?

Good places to check. Thanks.

 

[1987 GMC Jimmy]

Or a crummy aftermarket cable. My speedos perform fairly well using a somewhat worn out, abused, 33 year old cable on the bench, but they do the same thing as yours in my car. I have yet to find a cable that even comes close to the OEM design. I’m on the verge of saying screw it and just putting the dinosaur cable back in.

 

[Westislander]

[QUOTE="Matt69olds, post: 457076, member: 15079] ...
Cold speedo lube, more friction?[/QUOTE]

....lube makes everything quicker

 

[Matt69olds]

Oh great, is this going to make it to the square body quote thread?

 

[73c20jim]

using OEM cable, at least it looks like oem cable.

 

[ali_c20]

My speedo does the same and the faster I go the more accurate is my speedo. I have tried 3 different brand speedo cables and all of them sucked. If I ever find a good speedo cable that works as expected I'll post it.

 

[Byco]

What about LMC speedo cable? works well?