Guessing speed from power data (IMAZ)

I don't think you can come away with much comparison on any ride where you have to stop for lights.

This question is really about how aero your position is on the bike.  You can do a field test but outdoors you really want either:

- a relatively flat out and back course with no stoplights... or
- a velodrome

These both take wind out of the equation unless it drastically changes on you during the ride.

You can then use Golden Cheetah's aerolab, or something like this:

http://www.cyclingpowermodels.com/CdAEstimation.aspx

This gives you a decent estimate of your CdA without the expense of a wind tunnel.

I know that doesn't really answer your question, but there's no way to know how the course variations will affect your time.  By calculating your CdA, and repeating these test rides changing one thing at a time, you CAN work on improving your position, though.  That'll help you out during your race.  If you're curious, I averaged 143 watts and went just under 6 hours at IM Canada this year, my CdA was about .21

Leegoocrap is a good resource around here for aero tuning and Chung posts on BT occasionally as well.

Edit: as a side note, with an average of 157 on half IM distance, I'd recommend around 140 for IM.  The first half of the bike should have you wondering if you're going way too easy.

Try to ride with more even power. Your VI over 1.0 is wasted energy.  Both your HIMs it appears your VI is about 1.1.

Try for IMAZ to get under 1.04 you will be faster and help your run be best possible.

Don't have any specifics, but...

You could search other peoples race reports for IM AZ and look for power averages similar to what you're expecting. There should be a bunch of reports that include power data on this site, or if not, elsewhere on the internet.

Of course, take this information with a grain of salt. (Not so small) Details like conditions, aero, time in aero, stops, weight & power distribution will affect the final results.

Ignore me if you've already tried this.

edit- i misread. You said more even, not more power. Does 75% of CP sound reasonable as a starting point? Of course, conditions will dictate.

Edited by bdenehy 2012-10-23 8:31 PM

75% is pretty high for IM unless you are pointy end of the field.

What is your IF been on your longer rides?

I would suggest you start at around 70% for first 2 hours or slightly under the the 145 you have been riding at, then bump it up slightly at mile 80-85. Goal is to have your TSS be around 280. What was your TSS for your HIMs?

145/200=.725 IF

Is your 145 that you have done on your longer rides your NP or AP? 145 NP on hilly terrain is very different than 145 AP on hilly terrain or 145 AP on AZ course.

10 watts to high can ruin your run. 10 watts to low you can make up on the run.

I have yet to do an IM bike (7 of them) where my power was higher than what I did in training...usually within 2-4 watts of what I have trained to do. I'm not one that has a big improvement in taper plus I want to execute what I know I can do compared to what I wish I could do and pay for it on the run.

If I was you and had another long ride or two before IMAZ, I would set my target watts per hour for race and try it out on a long ride with run after. I have found holding back power first 60-90' (I'd do something like max watts 130 for your numbers)  really makes a difference for me for the rest of the race. Most folks overcook themselves on the first 2 hours of the bike and effect their whole IM. Using power in that critical point is huge advantage as you can check yourself. Tapered, out of the swim, out on the bike you will feel like super man. Use your power meter smart and control yourself. You will be so glad you did 130 miles in.

FTP?

Ok, so 135-155 should be your goal on the bike, with the sweet spot or goal of 145. As long as you've been able to hold that in practice, you'll be fine.

You don't have any flat sections of roads or races that you did this season that you can compare to. AZ is mostly flat with a few false flats and sometimes some wind. It's a fast course. Not as fast as IMFL, but still fast.

I based what I said on the 200 number, but having TSS so high for last 2 HIMS makes me wonder if your FTP was set wrong  (to low) to figure your TSS for those two races. Is your bike fitness similar now as to then or has your CP changed compared to your HIMs?

Good point.  The FTP was 192 at the time I logged those races in TrainingPeaks.  I've been working on building power with Jorge Martinez's plan over the summer/early fall.  I would say my bike fitness now is a little better, but maybe measurably better over longer rides.