You need to tell us your seat height in order to answer this question. Measure from the center of your BB to the top of the saddle in the middle.

ct BB to top of Seat is 79cm

Since one half of your seat length will be about 14 cm, the cosine of your seat angle will be 14/79 or .177, so your seat angle will be just under 80 degrees.

The graph and associated text is now on the cervelo site under the tech section

for us non math wizards, just how do you do this? BTW, the nose of my Flite saddle is 2.5cm in front of the BB, w/ BB to the saddle = 75cm

Thanks,

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David
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.

Since the nose of your saddle is 2.5 cm in front of the BB, the middle of the saddle would be 14 cm behind the nose or 11.5 cm behind the bottom bracket.

The cosine of your seat angle would be 11.5/75 = .153. I don't know if we would have any readers here that haven't memorized their trig tables. On the off chance you forgot them, you can look up in a table or a calculator to find that an angle of just over 81 would have the desired cosine.

You are riding one steep bike.

Oh, my trig tables....yes silly me. I do have them memorized! Thanks for tapping my memory....and the calculation:-)! And, so 81 degrees is too steep? Good thing I pushed it back a tad!

Really, thanks for the calculation.

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David
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.

Memorized! I've never even seen one!

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"...like every writer, he measured other men's virtues by what they had accomplished, yet asked that other men measure him by what he planned someday to do."

Art, thanks for the formula, guess I have to get that table as well, or check with my wife. sounds like we are all riding pretty steep here. Maybe I move it back a notch.

If you believe Dan, many riders are at or close to 80 degrees. I am at 80 right now, though I may notch it back for IM Lake Placid. I will see how the training rides go first.

No need to memorise trig tables; you can get close enough with a straight multiplication if you start with angle from vertical: horizontal distance * 58 / distance along seat tube, or horizontal distance * 56 / vertical drop. Then subtract the result from 90. Thus instead of inverse cosine of 0.153 (81.2 degrees), take 90 - 0.153 * 58 = 81.1 degrees. Close enough.

Art,

Why would you move your position back for Lake Placid? Would it not be better to stay in the same(fastest for you) position, stay aero, and spin up the hills? Seems most of them are not that steep, and there is still a good bit of flat, (or very light rolling) on that course.

I am going to test out a couple of different positions on the course over the next few weeks. The most important issue will be whether I can actually stay in the aero position for six plus hours. Having a great aero position won't help me if I can only stay in it for an hour or two. I will back off to about 78 or maybe even 77 degrees and raise my handlebars if required for comfort.

You just never know what works best until you try it.