What’s it take to bike 20MPH for 112 miles

Looking at my Nov. 27, 2010 Post, to get under 12 hours in an Ironman I will likely need to average at or close to 20MPH on the bike split…5:36:00…(19.5MPH = 5:44:36)…in ‘normal’ conditions…so what will that take I wondered…here’s what I found out.

Starting with my Dec. 4, 2010 post, I see that in a training ride on May 9, 2009, on a relatively flat out and back course…tri bike with ZIPP wheels:

total was 1:05:26 at 21.1MPH, 133HR avg, 213W avg for 22.9 miles

On a local out and back on Shearers road, which is very hilly, but not quite running out gears, on a August 14, 2010 ride, tri bike with ZIPP wheels:

shearer NS combined: 188W, 18.9MPH, 130HR avg, 15.387mi, 49:07

And on my road bike with non-aero wheels…the other 2 were on the tri bike…same Shearers road route on August 28, 2010:

211W both ways average…N with the wind, but mainly uphill: 18.3MPH, 133HR avg, S against the wind, mainly downhill, 21MPH, 135HR avg, so 19.7MH avg on 211W

This tells me that on the tri bike, with the ZIPP wheels, I’ll need 200-210 watts to give me the 20MPH…so let’s call it 200 watts for a round number.

So what does it take to be ‘capable’ of averaging 200 watts for 112 miles?…of course, no stopping included…when I say ‘capable’, ultimately, the balance between bike and run may determine a different final race goal.

Joe Friel in Training Long notes:

Power training zones are based on functional threshold power (FTP), which is the power you can maintain for an hour CP60

Joe also states that a 30 minute time trial by yourself, is roughly the same as a 60 minute time trial race, since you’ll push harder in a race…interesting…also noting that in a perfect world, a good rule of thumb is:

that average power decreases by 5% as duration doubles.  So an athlete with a CP30 of 200, would be expected to have a CP60 of 190 (95% of CP30)

So once we’ve established the FTP, what does that mean for our race power target?…Joe says that Ironman racing on the bike is done in Power Zone 2, which is 56-75% of FTP …Novice athletes at or below the bottom, highly trained elite athletes may be as high as 5% above.  So for my 200W race target, Joe would say my target FTP (or CP30) should be between @ 56%: 357W, and @ 75%: 267W…so if I got to a CP30 (FTP) of 300W, I could potentially race at 67% to meet my 200W goal to get to 20MPH.

Joe includes a table…he credits Copyright 2008 by Rick Ashburn…which suggests that for my 5:30-5:40 bike split goal, that with proper preparation I could ride at about 70% of Functional Threshold Power (FTP), so for my 200W goal, I would need a FTP of 286W.

The Endurance Nation (EN) folks have a slightly different take on things…I think that we’ve seen that before…although the race intensity table that they use is exactly the same as Joe Friel uses…nice to see the boys agree on something 🙂

It starts with establishing their baseline to establish the FTP level….they offer 4 methods…their baseline test is 42 minutes:

  • perform a FT Test (FTT)…which is 20 minutes build to all out…2 minutes easy spin…then 20 minutes build to all out again…and then take the ‘normalized’ power for the entire 42 minutes, including the 2 minutes easy

Other than a bit of a different idea on how to come up with the FTP number, they both agree on the race pace approach.

Final Thoughts

So it looks to me like I’ll need Functional Threshold Power (FTP) to be around  a minimum of 285 watts to be in a position to ride the Ironman 112 miles at 200W, or 20MPH…so in simple terms a CP30 of 285W, or the EN 42 minute test at a ‘normalized’ 285W.

Seems to me, therefore, that my early season training should focus on getting to that number…and then building off of that…will be _very_ interesting to see where I’m at at this point…probably will be very humbling.

I did very little high intensity work in 2010, so my recorded CP numbers for the lower time ranges, are very low.  On June 24, 2009, CP20 was 272W, so CP30 @5% less would be 258…my all time high recorded CP30 was 250W in 2006…so clearly I have my work cutout to get to 285W for CP30…like, since I’ve never in my life been there…or an equivalent CP20 of 300W…the local time trials that begin in April are 10 miles, so over 20 minutes, and may therefore be a good target benchmark to test the progress of that CP20 number.

No matter how you cut it, time to get the lead out of my butt, that’s for sure 🙂

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