I've been playing around with calibrating my Koso Speedo and managed to get it close but not as accurate as id like it to be and wondered if anyone can shed some light on it?

Its the Koso RX2 and it has 2 inputs for the speedo calibration, circumference and pick ups, heres a list of details

1770mm Tyre Circumference
2 Pick ups on prop shaft which has a circumference of 300mm
in one wheel rotation the 2 pick ups pass the sensor 7 times
the diff is a 3.14 diff if thats any help?

I had a go at setting it up with a guy at a garage the other day, he told me to put 1770mm in the circumference and 7 in the pick ups, i did this and the speed hardly increased, he then told me to just drop the pick ups til i get it right, although i did get it close it wasnt as close as id like and surely this is not the correct way of doing it?

i did mine by measuring the distance the car moved with one full rotation of the prop shaft, though thinking about it i might have done like 5 turns and divided by 5 to try and reduce the error. so i'd have entered 2 pickups, and the distance it covered in one full propshaft revolution, this takes the diff ratio into account.

So if I did the 1770 divided by 3.14 and 2 pick ups that should theoretically work?

I've just done what you said, measured the distance the car travels in one prop rotation and it was exactly the same as 1770 dived by 3.14.

This I'm guessing also confirms I do have a 3.14 diff? Alot of people doubted it when I bought the car because of how rare they are