Hi Mike
Not in Snow!!!!! You've got me there. I have not really noticed any loss of power and infact there is a fairly level section just before the top where I have even got back into 5th gear. A few years ago, before the tunnel near Domodosolla, there was a long pull and a full hairpin bend which was quite difficult with even a short outfit. One return journey did cause problems on the pass. We had stayed the night before on Lake Maggiore and endured a dreadful electric storm. An early start saw us heading for the pass with very little oncoming traffic. Then at the border we were shocked to find the barrier down. The pass was closed! The guards told us there was a 'pebble' in the road, brought down in the night by the storm. A bit anoyed we returned the 40 miles back to the lake to pick up another route through the Gotthard. The translation of a boulder or rock or half a mountain into a pebble did bring about some laughs though.
Happy travel BarryB