1999 Accord Speedometer Adjustment?

I have a 1999 Honda Accord on which the speedoment is off. The speedometer
reads 64 mph when going 60 mph. The speedometer error increases as the speed
increases. I have the service manual but there is no mention of an
adjustment. Is there any way make an adjustment?

Thanks.
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Baton Rouge, LA

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I don't know of any.

Look at the discrepancy as a way to keep from speeding. Actually, since you
know what the difference is, you can drive with the speedo reading a little
higher. I used a GPS and a long, straight stretch of road to "calibrate" my
speedo and make a little chart. After a while you won't need the chart.

Bearman

 

I am not aware of any adjustment, short of getting bigger tires.
Speedometers always show a little too high. There was a thread about
this in the BMW NG recently. The service limit for BMW's is actual speed
+ 10% + 2.4 mph. So at 60 MPH the speedo could show 68.4 and BMW would
say that the speedo is within spec. As a practical matter, speedometers
are usually quite accurate instruments, but they are calibrated to show
a little too high.

 

according to honda and federal laws, the speedo is allowed a 10%
variance either way.
Chip

 

What law is that anyway? I'd like to print a copy to have in my glove box.
I'd like to see the official BMW spec sheet that says they allow +10%
+2mph, no minius allowed?? Sounds more like a "newsgroup expert on BMW" then
fact.

 

Here is the BMW reference: http://ackthud.com/shawnfogg/pics/speed.jpg.

Regardless of local law, if your speedometer said 75 and a friendly
police officer clocked you at 78 and gave you a ticket, you might think
of asking BMW to pay that ticket. BMW (or any other auto maker) is
probably not too intrigued by that prospect, so they adjust the
speedometer to show a little high rather than a little low.

 

Have you changed your tires and/or rim size?

 

I have changed rims but they and the tires are the same size as the
original.

 

Well there you go I asked and you supplied. I have to admit, it looks legit
to me. I guess that's why the old police car's speedos used to say
"Calibrated" on them.

 

I read the document you linked and I noticed an interesting fact. The
speedometer is calibrated to show a higher value on purpose, because the
odometer records the correct mileage. They could just as easily
calibrate it to show the proper speed, but they choose not to.

In my old Accord the speedometer was surprisingly accurate with less
than 2km/h over at 80km/h. The difference would increase slightly to
5km/h at 140km/h (I tested it against a gps). I haven't gotten a chance
to test this on my Prelude, but I have a feeling it will be within the
same limits.

I wonder why the BMW speedometer is so far off. I mean 10%+2.4mph is
quite a bit of an error. If they would use the same tolerances in all
the other parts inside the car, you'd probably drive a few miles and
stuff would start falling off...

Cosmin

 

A slight change in the outside diameter will make a difference, and it seems
your error is linear. Is the error the same percentage (truly linear)?

 

| > > Is there any way make an adjustment?

your gearbox has a removeable device called a speed sensor
( mine failed in 1-04 ), ask a mechanic / parts shop whether
this is adjustable