I have seen as much as .015 , BUT you have to remember, what is your starting temp? It will grow .015 in April when its 50* out, but it may only grow .011 in July when its 90* . After a while you get a good idea of where you may start and where it ends up. Scary to think in the winter the lash may be .008 or less , always a little scary to start it at temps below 40 but who races in that weather? Block heater is your friend I guess at that extreme