Speedo read 5mph over at all times

[Alaskanredneck]

I dont know whats wrong with it but my speedo always reads 5mph over. I have 235/75/15 tires on just as the door sticker says. someone told me there may be an ajustment wheel under the dash and that i can just click it a few notches. Anyone here ever head of that or have any other ideas??

 

[boggs1227]

no adjustment that i know of...these speedos are known for their rabbit-iddas.either the head has gone out of balance or the cable needs to be lube/replaced or the speed sensor in the transmission has gone out of round ,and is needing replaceing ( cheap part little plastic colored gear ,they come in diff colors depending on your gearing i think and year model)

...could be also ...ever had the transmission worked on by a shop ?? maybe they installed the wrong sensor and your getting higher than normal reading .


mine is perfect till you get to 65 once there it starts to bounce and funny enough it only does it when the trucks suspension hits a dip on the road tho

 

[Alan_V]

I dont know whats wrong with it but my speedo always reads 5mph over. I have 235/75/15 tires on just as the door sticker says. someone told me there may be an ajustment wheel under the dash and that i can just click it a few notches. Anyone here ever head of that or have any other ideas??

Do you have new rubber on it? Manufacturers alway build in a cushion of a few MPH so that as the tire wears (smaller circumference) the speedo gets closer to accurate. If it were accurate with new tires, you would technically be speeding as they wear and the mfg could be considered responsible. Usually it's about 5%, but I could see vehicles with deeper tread having a greater cushion.

 

[Alaskanredneck]

no i have put new tires on it before but it always shows 5mph under what the radar things say. how would i go about lubing the linkages and what kinda lube should i use. btw it does not hop at all but some times on a cold morning my tack will work when i first start to drive then drop off like its not conected then start working again just before i get to work. I dont know if there related but figured id throw that out there

 

[Alaskanredneck]

Anyone?

 

[Willard]

5 mph off a radar detector is perfectly acceptable.

As already stated, exact tire dimensions make a difference, where in the speedo gear, etc. The vehicle speedometer isn't designed to be that accurate, just to give you a ballpark. Between your speedo being off, and the chance the radar detectors aren't perfect either, I wouldn't worry about it.

 

[Alaskanredneck]

Well when i go to court in two months i'll be sure to let the judge know that i was in the ballpark of the speed limit (lol) for some reason the cops here are stepping it up i got a ticket for 6mph over. Maybe it was my sarah palin bumper sticker. So any ideas on hot to lube the speedo gear and cable?

 

[Willard]

A ticket for 6 over? That sucks. I'd be tempted to throw it out the window and never look back. A friend did that once, somehow he never got in trouble.

I'm not sure lubing the gear and cable would really help. In fact I don't think it would be very easy/possible to lube the cable. You could take out the speed sensor from the transmission and lube that, but like I said, I doubt it'll make a difference.

 

[Alaskanredneck]

Well i guess i just better keep an eye on the speedo and do the math lol

 

[CDW6212R]

FYI, those mechanical cable driven speedometers can be off due to handling. The ring which the cable spins and the speedometer rings must not be touched. Someone may have had the speedometer opened up and touched some of that. It wouldn't be much difference, but every bit counts.

You can have the speedometer recalibrated, that's not cheap.

FYI, the Explorer pre-2002 speedometers are most accurate with 30" tires, not the old 235/75/15's(29"). Good luck,