hi all, new to ford mods, been searching for a solution about my speedo.
my speed is 8km below what my speedo is saying, im driving a 93 eb series s-xr6 (pics coming soon) running 225/50/16, only owned the car for a week, and its giving me the s**t with the speedo. any solutions would be great

Its possible the car originally came with 15" rims and they have been changed to 16's, therefore it could have the wrong speedo gear on the speedo sender.

Might pay to pull the speedo sender out of the gearbox quickly and see if it has a black or grey gear on it. You'd be looking for a black gear to get the right speed... Assuming its an auto too, I think the manuals used a different gear.

Even then, it could still be 3 to 5km/h out, with the speedo still showing a higher speed. All Ford speedo's for the past 20 years have had a 3 or 4km/h discrepancy to allow for drivetrain error, cruise control and tire wear.

My simple fix is it sit at 105km/h indicated and problem solved. Then you'll see how many speedo's on the road are out.

thanks for the info.

whats getting me is the tyre placard says 225/50z r16, and doesn't give any other size profiles or rims. the speedo is out 10km/h but most have about 3km/h leeway for wear and tear errors.
its a auto atm, until this heat dies down, then comes the manual conversion from my old eb series 2

My AU reads 5km/h out (checked using diag.) and my BF reads 8 k's out (checked with police mode).
The AU has 18's but are same rolling diameter as standard. The BF has standard 16's. I think my old EA was about the closest (within 3km/h).

Most speedos from most manufacturers read 5km/h more than actual road speed.

Maybe the diff's been changed. Bung LSD and someone got a new diff but different ratio. Going from a 3.45 to say A 3.23 but leaving the rest the same will add a 6km/h speedo error.

I've never known a falcon of any type to be more then 4km/h out compared to speedo indicated if you have the drivetrain/gearing/ecu all setup correctly.