Frame setback

[LegendRider]

Does anyone know the frame setback for a stock 58cm Legend? I purchased my frame in 2000. 58cm seat tube, 57.5cm top tube, 7cm bottom bracket drop, 73 degree seat tube angle. 73.5 head tube.

Thanks in advance.

[dbrk]

Setback is easy enough to measure and, to my knowledge, Serotta has never offered this number in their charts. Find the spot in the middle of the level of the toptube and drop a plumb-bob through the center of the bottom bracket. Now measure from that spot on the toptube to the center of the seat collar, voila, setback...

dbrk
lots lots lots of setback...

[Orin]

Easy to calculate too...

It's seat tube length * cos(seat tube angle).

17.0 cm for 58cm and 73 degrees.

Orin.

[dbrk]

I do Sanskrit because math is hard but it just doesn't seem right to me that a bike this size has that much setback. I think the measurement has to be taken center to center rather than to the top (effectively shortening the number) because, well, I'd wager donuts that this bike's setback is no more than 16ish...

the numbers don't lie, i know, i know...

dbrk

[Needs Help]

I do Sanskrit because math is hard but it just doesn't seem right to me that a bike this size has that much setback. I think the measurement has to be taken center to center.

As long as the seat tube length listed is center to center, the trigonometry comes up with the same length you get by measuring.

[Bittersweet]

Merckx likes to list setback and a quick check of his math confirms Orin's post. 62cm frames (ST) has a 71.6 degree seat angle and 19.5cm setback. Math check says 19.57cm which is pretty close to what Merckx lists.

Interestingly, Colnago lists a 58cm with 73 degree seat angle as having setback of 16.4 which when math checked shows 16.95cm.

Who do you trust Eddy or Ernesto?