BRZ - what does it use to determine vehicle speed?
 

Searched some but didn't find the answer. Does the BRZ use wheel speed to determine vehicle speed? I have a different final drive ratio now, and the speedo seems off compared to GPS displayed speed. But I can't reconcile why the final drive ratio would have affected it? Thanks for any info you might have - Joe V

Rear wheel speeds. There is always a difference between GPS and displayed speed.

Speedo is off in all new cars even stock. By 4-10%. IIRC was ~8% slower in my gt86.

Perhaps you should also disclose what else is different on your car, aside from your final drive.

I believe the speed is determined by the ABS sensors so changing a final drive should have no effect on detected speed. Wheel, tyre size and even tyre wear will effect the detected speed however.

Wheel speeds (specifically rear). FD doesn't affect speedo.

so then is the speedometer not affected by changes to the rear end?

Speedo is affected if you change tire/wheel diameter.

How is that not a clear statement?

hahhah. it was totally clear. I guess I just hadn't had enough coffee yet because apparently I didn't even read the entire sentence. may bad

LOL I thought I was missing something somehow!