Hey guys, it's been awhile since I've posted a question, and I thought it was about time again.

I've got a NA 87 and its speedo is just horrible. When it says I'm doing 80, I'm doing 71, it's all basically off, starting at about 55 or so. I don't remember everything, but it wasn't exactly great to see, you know?

So, any ideas about what I can do to fix it? Can I do anything on my own, or should this be one of those "leave it to the guys that know what they are doing" jobs?

 

Low profile tire size can do that.

 

Running the exact tire size recommended.

 

My speedo is off by 5 mph and i'm on the 15 inch wheels with stock tire size.

 

My speedometer reads low, too. (6-8mph as compared to those "Your Speed Is..." radar unit things, as I drive by.) And compared to my everday car, the odometer undereads by 14%. (100 miles in my Ford = 86 miles in the RX7.) I'm guessing that someone swapped in a different rear end, perhaps from an auto-trans car???

 

I got out of a speeding ticket once when I told the Judge "I thought the speedo was off, but I didn't know how much."
"Can you suspend this ticket if I get it calibrated?"
"Where do I take it for calibration?"

He said: "Bring me the receipt, & I'll suspend the ticket."

It only works once..