That seems to have done the trick but the powertap seems to be a reading alot lower than my old polar (about 30 watts) somebody said this may be because the polar does not record zeros and my powertap does record zeros is this true?
Also my friend has an srm and when riding along together his is usually 50 + watts higer than mine (and he is 4 kg lighter) but this is mainly on the flat, on the climbs their is not much in it.