So I realized and determined that my speedometer is off by 4-5 mph via my gps on my blackberry and also vs. my wifes car. My 99 civic LX is completely stock with stock rims and tires. Is there any way to reset this or anything at all I can do?

As always...................thanks for the help!!

 

Factory every speedometer is off. Typically they areestimating above the speed you're going to keep you from getting a ticket.

Different tires have different tread widths even on the same sizes which results in different sidewall sizes as well, this will also effect your speedometer reading.

It's really not that important, and if it is to you then you need to experement with tire sizes and find the closest for you.

 

my 95 is as follows.

at 45 im doing 40

at 55 im doing 50

at 65 im doing 59

at 75 im doing 67


i found one of those "your speed" things and drove by it multiple times at diff speeds to see how far off my speedo is.

now when the speed limit on the interstate says 70 mph, i do about 77

 

Thanks for this info. Mine is VERY much the same. I travel 98% on the interstate and I generally travel 80mph but im actually going 75-76. However, my 94 LX was spot on. Oh well, this is good stuff to know!!

Thanks again fellas

 

to add on the tire aspect, i think its every 10lbs your tires are underflated will make your spedo off by 1.5 mph

 

Yep, completely normal, and in fact (with very few exceptions) all cars' speedometers will be more off the faster you go. This is because it's more important to calibrate it accurately for around-town speeds than it is for highway speeds. An exception is the Audi (I believe) R8. Its speedometer numbers actually get closer together as it goes up to counteract this effect.

Believe it or not, the Civic actually does register the correct speed. My scanguage device reads my speed directly off of the speed sensor, and the speed that it reports corresponds exactly with what the GPS tells me, which is always a little lower than what the speedometer reports. The limitation is in the analog dial itself. Digital speedometers usually don't have this problem, as they just report what the speed sensor says.