Hermes,

Thanks for posting the Lance pic - this inspired me to get both my bikes out and have my wife photograph my position on them as I would normally ride. Several note worthy differences, I am a bit more stretched out on the Tarmac. My back is flatter as well. I have campy on my Simoncini and Shimano on my Tarmac, The campy hoods are further forward and I don't tend to grip them, I do grip them on the Tarmac. So two differences, one is the reach, the other is how I ride the bars/hoods. I will take the gamble on the short stem - if anything, it will get me closer to my other bike fit.