I currently ride a 53 cm road bike (54cm top tube) and that is the perfect fit for me. Now I am in the market for a TT bike and have an opportunity to purchase a 52cm P3. The 52cm can either be used with the seat tube at 75 or 78 degree. At 75 the top tube measures 54.8 and at 78 the top tube measures 52. I think this sounds about right for me. I know fit is the most important aspect, I speak from experience. My last road bike was too long for me and I was constantly complaining of shoulder pain. My current set up has a 54 cm top tube and is great. I need the shorter top tube due to my short torso. That is why I have the suspicion I would need the 52cm Cervelo over the 54cm. I am afraid the 54cm would put me in a stretched out position and I don't think that would be ideal for a TT bike.

This 52cm P3 has come available and would be a great deal for me but if it isn't the right size, I definately don't want to buy it. BTW, I can't test ride it because it is in another state so that isn't an option.

Any help you could give me would be greatly appreciated.