How To Estimate IM Bike Split
I am a noob in the world of Power and I just listened to Coach Rich's Power Webinar. The question I am left with is how do you accurately estimate your IM bike split? My goal is to properly determine my race day IF using Rich's fancy, smancy TSS chart but to do so begins with a realistic bike split estimate.
Is there a chart or at least some guidelines using my FTP to SWAG a potential bike split for me at IM - Louisville? Thanks!
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Used to riding centuries? If so, what pace?
Or at least, what pace on your longer rides PreEN?
What kind of terrain do you train on?
Remember it's a 'should' pace, not a 'could' pace.
Weight?
Previous bike times in a HIM?
I think the best thing for someone with no IM experience is to be patient on this question. Meaning, there are two race rehearsals at about 6 and 3 or 4 weeks before the IM, when you'll ride for 112 miles or 6 hours, whichever comes first. On the first one, you'll experience a sharp learning curve, and apply some of those lessons to the second rehearsal. After the second rehearsal, you should have a good ball-park estimate of what your time for the 112 miles should be. Many folks here would say that the race-day time will be about 10-15 minutes faster than what you'd extrapolate from that second race rehearsal; they also may say that for your first IM, it's good to be conservative and go with your actual RR time (unless you are already a strong, fast, and experienced triathlete.) Once you've got those two rehearsals under your belt, if you're still anxious about how to estimate your time, come back to the forums for more help.
Until then, it REALLY doesn't matter what your estimated time is going to be. While it's fun to fantasize, the whole point of the EN racing strategy is to go into the race with hard data dictating your pacing. Wait until you've got that RR data.
Dan,
For my first IM EN style I used the race rehersals as Al mentioned. Going in to that you will have some longer which you can help to determine how long you think it will take you.
As for a SWAG yes it can be done with some of the questions the Mike and others have asked. Just remember it's still a long season until you get to Louisville and that why the final determination comes later but I understand wanting a time goal. Just be careful about chasing a time goal as a really windy day or heat can really affect your finish time a bunch.
Gordon
http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=2254842
@ Al is right you won't know until your RR.
Maybe someone performing the same race and with similar body composition could provide you some feedback to help you sleep at night. Again, we stress with training and racing with what you earn.
Race splits are fun to try to predict, but its often a useless exercise, as even two riders with very similar watts and weight can ride very different times based on execution skill.
Hey guys, thanks for the input! I guess I should have given a little more background on myself. I have actually done a couple IMs previously but just did the LSD training thing and really had no idea how to execute a race...other than watching my heart rate..which proved not very helpful!!! So in a way L'ville this year will be my first IM....EN style!
Anyway, I am a decent swimmer (1:12) and a good runner (52 VDOT) but am totally new to biking in the past few years and pretty much stink at it! So I really want to improve my bike split (previous best is 6:39 at CDA) but obviously not at the expense of hindering my run. I am hopeful that my time in the OS doing FTP workouts will really pay off this year.
I just ordered a power meter through Rich last week so any other tips people have to help me get rolling with training with power are appreciated! For example, once I get my PM installed should I continue to waer a HR monitor in training? In races? How important is it to be able to see my TSS points in real time on my bike display?
Thanks again for all the feedback!
Power and HR together can be a useful race day gauge. We talk a lot about riding XX% FTP but, for example, there's a difference riding 70% when it's 60 degrees outside compared to 90 degrees. Your body is going to be more stressed trying to ride the same watts at a higher temperature. That's not something your power meter is going to monitor but your HR will.
But I now have the FR 910 and it comes with a super comfy HR strap, so I have been wearing the HRM.
I am prepping for IMSG.
This past weekend, I spent 4 hours on the drainer at 72% FTP. My heart rate was beautiful in the first 2 hours. But despite drinking, I watched it creep up almost 20 beats by the time I was getting off to run. This was huge! My VI was 1.01- meaning I was perfectly steady across the entire ride (easy enough to do on a trainer). But I really felt it.
So in my 60 degree basement, with a fan blowing, I still could see that I had not done a great job on race prep fluid intake.
If you train indoors at all- the HR can be an excellent extra data point.
How about you give this site a try? www.triathloncalculator.com/
I'd actually be interested to know how anyone who has their past data and splits compare to what is spit out.
I've used that before for fun after the fact, and it is within 1-2% for me usually. I put in the data from my most recent race (IM AZ), and found it was: 2 min fast for the swim, 1:30 fast for the bike, and (ugh!) 6 minutes fast for the run. But then, I was injured with plantar fasciitis and did not get good run training the last six weeks going into the race - I fed it a 5K time I'd extrapolated from a half marathon I ran for my race VDOT two months before I got injured.
Bottom line: it is probably a very good model for predicting your "should" bike time based on a realistic FTP, which is what I put in where it asked for 20 minute TT wattage.
Of course it won't be perfect, and as Steve says he ended up racing faster than his RR. But we've covered that before as well. Faster setup, draft effect of 2000 athletes, traffic stopped, etc.