Road Cycling - Another size question

I'm interested in getting a new road bike. Wrenchscience.com tells me the ff:

Your Frame Size is :: 55cm Center-to-Top / 54cm Center-to-Center

Also, my LBS tells me that I'm a size 55.

My questions are:

1) On bikes that don't make a 55, would I be closer to a 56 or a 54? I'm 5'10.5'' with a 32.5" inseam length.

2) Is Center-to-Center the top tube length?

Thanks
:confused:

The measurement you are talking about in reference to "Center-to-Center" is the seat tube length. NOT the top tube length.

If there is no 55 cm bike try both the 56 and 54 and see which one feels best. That will be your best deciding factor.

Good luck!

FWIW it is easier to adapt a bike if it is slightly small than slightly large. The seat post goes up a bit and maybe $30-50 for a longer stem (or a lot more depending on brand). Close eyeballing of Giro and soon Tour De Fr riders will show they tend to ride a bit small. Notice that the seats are high above the frame and tend to be 3-4" above the bar. If you get the bike new and are certain of your comfort set up the LBS will typically change out the stem early in the new owner time frame if you find it too short/long as part of the service after the sale. Ask about this at the shop. Most stems these days are easy changeouts. Steve

Two bikes of the same "size" may differ in standover hieght because they measure to different points on the top tube (ie the centre or the top), OR because the bottom bracket is a different height off the ground.
Given that all the bikes in your size range have adaquate standover clearance, the important dimension is top tube length (or the horizontal equivelent if the TT is sloping).
Make sure that shorter bikes do not suffer from interference between your toes and the wheel when you turn the wheels.

Don't forget that the top lenght eill also change bike to bike. I would ride both and see what fits you best. I'm 6' with a 32 inseam and ride a 56 c-c.

Generally, yes, it is easier to adapt a smaller bike UNLESS you are a mutant like me. I am also 6' with a 32" inseam so a 55 or 56 would theoretically be a good size. However, I have longish arms (35" shirtsleeve) and torso so I need a long top tube. I can barely make a 58 or 59 fit and that takes a 140 mm stem. One day I hope to get a custom frame. My point is that seat tube length is not the only concern. Sheldon Brown advocates starting with the top tube/reach measurement. You can always raise or lower the seatpost, even putting in a longer one, but there is a max on the stem length you can use. If I could find a 150 I would buy it.