I know speedometers dont usually show your exact speed on the dot but mine is usually fast by about 5 mph even at sub highway speeds. If the speedometer says 70, im actually doing more like 65 or 64. Just curious, does everyone have this problem or is it just me?

 

My speedometer is pretty accurate. Do you have stock size tires......225/50/16. If you do, and they are nearly worn out, that would contribute to your problem.

 

Do you have stock wheels/rims?

 

yes. i have been using the stock rims and original tires which are worn a bit but still have a little life left.

 

Hmm, how are you telling that your speedo is inaccurate?

 

Mine does this as well. In fact, i have a power fc and the speed shown in the commander and my speedo differ by 8-10 kmph ie 4-5 mph.
Don't know the cause but I would like to fix it.

Raj

 

the power FC shows your speed too? sweeet!

 

Find a GPS to borrow.
I use my Garmin to check speed mine is off only +/- 2 mph based on cruise on steady at 60mph

 

Also, check these threads:

https://www.rx7club.com/forum/showth...hreadid=165838

https://www.rx7club.com/forum/showth...threadid=26343

https://www.rx7club.com/forum/showth...threadid=22619

 

Keep in mind that if your speedometer is off, your odometer could also be off which could mean you actually have less or more miles than your odometer shows.
-Kevin

 

You can easily recalibrate the speedo guage using the tach.

 

how?

 

PM me if you want my number and I can walk you through it. It's pretty simple and takes about an hour or so to do it.
-Dave

 

Using a GPS, I have noticed that my speedo is about 5-6mph optimistic at freeway speeds. My stock tires are maybe 50% worn.

 

Hmmm...I guess I'm the lucky one. My speedo seems to be exactly on if I compare my speed to my rpm using the known gearing of the car. Redline in 3rd gear is just a tad over 100 mph....

 

try cruising at 60 between mile markers, thatll tell for sure.

 

Or you can see from the mile markers how far your odometer travels in a mile to get a good ratio of how much your speedometer is off.