hi all, just changed from 235/45/18's to 245/35/19's on my bf xr6t.. I plugged in the sct tuner to reset parameters but as it only has 2x custom tunes installed it didnt have that option... upon taking it for a drive it doesnt seem my speedo is out, judging by other traffic and speed zones... so my question is .. is the speedo electronically controlled from the transmission or at the rear wheels..? do I need to speak with my tuner about resetting it... I think the difference was about 8 revolutions per km doing the maths..