Fast Reading Speedo on my miata

[moggollon22]

I just bought a black and tan 2004 LS 6 speed great car but the speedometer reads about 4 mile per hour fast at highway speeds. What can cause this and how can I fix it?

[— kung fu jesus —]

What size are you tires?

[moggollon22]

My tires are 205 40 R 16 83W. They came with the car.

[WASABI]

I just bought a black and tan 2004 LS 6 speed great car but the speedometer reads about 4 mile per hour fast at highway speeds. What can cause this and how can I fix it?

First, welcome to our site, and to answer your question, there are two reasons I can think of off the to of my head.

1: Non stock tire size.

2: Gauge needles have been put on incorrectly (You would have to know if there are custom/aftermarket gauge faces).

I hope this helps.

[moggollon22]

My tires are 205 40R 16 83W They came with the car.

[— Phatmiata —]

Are you running aftermarket gauge faces, or stock?

[moggollon22]

The gauges look stock to me.

[— kung fu jesus —]

4 mph keeps you honest.

[moggollon22]

I've been wondering if the car might have the wrong rear end for the 6 speed trans. Can I tell from the vin # if the car was originally sold with the 6 speed trans option? I know the final drive ratio is slightly different for the 5 speed vs 6 speed. It might be a small thing but the shift knob is for a 5 speed.

[— kung fu jesus —]

Yes, you should be able to get that from Mazda USA. There is a customer service number where you can give them the VIN and they will tell you the options. I believe all NB LS versions came with the sixer.

IIRC, the speedo on the NB is electronic, not mechanical like the NA.

[moggollon22]

Thanks KFJ I'll give Mazda USA a try,