Understanding a Serotta build sheet

[dekindy]

I received a build sheet on a bike that I am considering but am not certain how to read it. Horizontal Top Tube Length is 58cm and it has a 7 degree slope. Does this mean that it has an effective top tube length of 58 cm or would the effective length have to be calculated? If the effective length has to be calculated, what is it? The Head Tube and Seat Tube angles are both 73 degrees and the seat tube length is 53 cm.

[Mr. Butterworth]

The Top Tube Length as listed in the upper left hand corner is EFFECTIVE (HORIZONTAL) TOP TUBE, not actual. Actual top tube length is derived from a calculation in the program and is listed elsewhere on the sheet.

[Smiley]

if it lists the HTT then its a virtual TT length since they spec'd a slope. The ACTUAL TT length is meaningless to u and the fitter

[dekindy]

I guess that I assumed that this was true for the seat tube also. However an ebay seller claims that he has accurately measured the seat tube and it corresponds to the 59cm on the build sheet and I see no reference to the virtual seat tube height on the build sheet. 62 is in the serial number so he believes that the virtual seat tube height is 62. If this is true, why the inconsistency between the top tube being the virtual measure and the seat tube being the actual measure? I almost made a huge mistake if this information is true and I believe it is as he appears confident in his measurement. I am really confused.

[dekindy]

Now that I compare the standover height at the seat tube between my level tube Legend and the 4 degree sloped CDA build sheets, both indiciating 59cm seat tube length, they are virtually the same. My Serotta trained fitter says that the CDA will fit me well so I guess maybe I should just believe him and make a decision on the frame?

[dave thompson]

I read the seat tube length (actual) as 59CM, the (virtual) seat tube length as 62CM (based on the serial number) and the (effective) top tube length as 57.2CM.

Worst case scenario is that there won't be an abundance of seat post showing, depending on your seat height. You can treat this fit as having an upsloping top tube, thereby making the front end taller. If the bike is still built up, ask for the measurement from the ground to the handlebars. The seat tube length isn't the critical dimension in this case.

You could also ask the seller to set the seat height to the same as yours, measure to the top of the saddle, compare that and the bar height and then compare those measurements to your best fitting bike. Pictures of this set-up would help you visualize what you would be getting.

[oliver1850]

Visualize it as a traditional road frame with a level top tube. It would be 62 cm c to c, the top tube would be 57.2 c to c, and the head tube is 224 mm. It is a big frame with a short top tube and long head tube for its size.

For comparison, my Concours (level TT) is 60 cm c to c with a 58 TT and 202 mm head tube. The largest Cannondale CAAD frames were 61 cm with a 60 cm TT and 219 mm HT. They were sold as 63 cm nominally, but Cannondale measures them to slightly above the top tube.

What size is your Legend? How long is the TT and HT?

The frame you're looking at would be a perfect fit for me. I like the traditional look of a level top tube though.

[dekindy]

I need the taller head tube but the seat tube is just a little too tall so I decided to keep the Colorado that I already have. I just wish that I liked the color of the Colorado better but it rides great so it will have to do for a backup bike.

[oliver1850]

If you like the TT and HT lengths, the only thing left to consider is the standover. At 86.8, it's only about 1.4 cm more than my level top tube 60cm Concours. If you're riding a 60 cm Colorado, it comes down to whether you are comfortable with that much less standover clearance.

[Ken Robb]

this bike has a BB drop of only 7cm while most recent Serottas have 8cm drop so the standover here will be a bit higher.