^^ you mean frame might be too small? it's possible. riders my height usually go for 58, not 56. But the bikes built these days all tend to have tall head tubes, which puts me more upright than I'd like. I ride competitively, and my ideal position is to have the back parallel with the ground. To do that, i need to go a size smaller, and compensate the reach with a longer stem. not everyone does this, but if I were to pick between getting lower (while remaining reasonably comfortable), and spending $1000's on aero equipment, I'll choose the free option. besides, I ride a 56 on the caadx as well. as I mentioned, the difference in geometry between the two bikes (one that wobbles and one that doesn't) is pretty small. idk. I'm not too worried about it at this point. i don't normally take my hands off the bars like that anyway.