IM Bike pace target at new weight?

Mar 31, 15 8:13

Post #1 of 17 (3212 views)

I wanted to get some feedback on other people's experience with weight loss exceeding previous race weights and effects on the bike pace.

My previous weight has been around 195 to 205 for my six 70.3 and one 140.6. This time around I am headed towards 180 pounds for IMTX. I just completed 70.3 Puerto Rico at 195 and had a very easy 20.5 mph average and had a better than usual run based on finish %. 70.3 PR and IMTX are both flat so weight might not mean as much vs areo position during the windy portions.

Any thoughts on my target of 20.0 mph for IMTX? I am currently chasing the silver man on my computrainer at 20 mph for the first half of IMTX file which is rolling uphill of .1 to .8 grades. Back half is the reverse. It's a very flat course so I could target 19 or so for the first half and faster for the last half.

I have a modest run pace target of 10:30 / mile that should be ok based on my current training at 8:30 / mile for 13 - 16 long runs.

A little more info on past races for you:

Swim middle-back of the pack usually around 65% finisher
Bike middle-front of the pack usually finish around front 35%
Run is right down the middle at 50% finish times.

2015 IM TX (180 lbs) ???
2015 70.3 Puerto Rico (195 lbs) Swim 58%, Bike 28%, Run 37%, Overall 34%
2014 70.3 Boulder (205 lbs) Swim 65%, Bike 43%, Run 45%, Overall 45%
2014 70.3 Florida (205 lbs) Swim 62%, Bike 39%, Run 52%, Overall 52%
2013 IM Lou (200 lbs) Swim 66%, Bike 41%, Run 66%, Overall 52%
2013 70.3 Hawaii (200 lbs) Swim 75%, Bike 29%, Run 63%, Overall 46%
2012 70.3 Augusta (190 lbs) Swim 42%, Bike 13%, Run 40%, Overall 23%

All 70.3 Bike avgs were 20 - 22 mph
IM Lou Bike avg was 18 mph

Thanks for the feedback.

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 8:20

Post #2 of 17 (3201 views)

Since you are using a CT, what is your FTP? You should race IM at a percentage of FTP. Your Power/Weight ratio will be slightly better, so you should be faster on the hills.

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 8:27

Post #3 of 17 (3184 views)

Attempting to pace by speed is fraught with more dangers than pacing by power. Even the slightest head or tail wind, up grade or down grade have huge affect on your speed If you attempt to maintain a specific speed your power will be all over the place and defiantly not optimized.

If you really want to pace optimally, buy a used Powertap or other recognized quality power meter.

Hugh

Genetics load the gun, lifestyle pulls the trigger.

Re: IM Bike pace target at new weight? [jdais] [ In reply to ]

Mar 31, 15 8:29

Post #4 of 17 (3181 views)

jdais wrote:

Since you are using a CT, what is your FTP? You should race IM at a percentage of FTP. Your Power/Weight ratio will be slightly better, so you should be faster on the hills.

I haven't done a FTP ride in a long time. But I ride easy at CT watts of 200, medium around 225, high around 240-250. I am 42 and my target training rides are around 130-140 HR which I can stay within for 4 or 5 hours at 200-220 watts. That gets me around 20 mph on the 3D course.

Re: IM Bike pace target at new weight? [sciguy] [ In reply to ]

Mar 31, 15 8:34

Post #5 of 17 (3175 views)

sciguy wrote:

Attempting to pace by speed is fraught with more dangers than pacing by power. Even the slightest head or tail wind, up grade or down grade have huge affect on your speed If you attempt to maintain a specific speed your power will be all over the place and defiantly not optimized.

If you really want to pace optimally, buy a used Powertap or other recognized quality power meter.

Hugh

I totally agree and I wasn't meaning that a target speed on a small scale. More on hour targets and end time. I have a races under my belt and generally pace off HR range of 130 to 140 for short term indicator.

I was trying to determine my fast pace/time based on loos of 15 lbs or so and that is hard to quantify based on HR and no power.

Any ideas?

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 8:50

Post #6 of 17 (3147 views)

Maybe someone who knows the power to weight calculations and can apply that to a given course could use the following:

Weight 200, Power 210, speed 19 mph on IMTX course

Weight 180, Power 210, speed ?? mph on IMTX course

I guess that's more in line with my question. Given that I generally ride the IMTX 3D course on CT at 210 w avg with a 135 HR avg.

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 9:03

Post #7 of 17 (3129 views)

I'd use best bike splits website for IMTX course. It's pretty darn accurate if the winds are close (model vs actual). It will also give you an idea of how tinkering with your watts will impact your time.

Re: IM Bike pace target at new weight? [3Aims] [ In reply to ]

Mar 31, 15 9:21

Post #8 of 17 (3096 views)

3Aims wrote:

I'd use best bike splits website for IMTX course. It's pretty darn accurate if the winds are close (model vs actual). It will also give you an idea of how tinkering with your watts will impact your time.

Not sure I did it right but I put in 200 lbs on my profile and got back these results with my 2013 P3 and 404 front 808 rear. 20.96 would be nice lol but I don't know about that in reality. I certainly think 200 watts is easily doable. I also had 10 knots at 270 (which I think is coming from the west)

CourseIronman TexasDistance111.33 miTime 5 hours 18 mins 41 secs Avg. Speed20.96 mphAvg. Power196.01 wattsNormalized Power�198.85 wattsVariability Index1.01Intensity Factor�0.62Training Stress Score�205Watts/Kg2.22Avg. Yaw7.64 �BikeP3

I then changed my weight on the profile to 180 and updated the race and got:

CourseIronman TexasDistance111.33 miTime 5 hours 15 mins 42 secs Avg. Speed21.16 mphAvg. Power196.24 wattsNormalized Power�199.29 wattsVariability Index1.02Intensity Factor�0.62Training Stress Score�204Watts/Kg2.4Avg. Yaw7.55 �BikeP3

So a three minute savings? Sound right on a flat course?

Last edited by: GA_TRI_DAWG: Mar 31, 15 9:25

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 10:38

Post #9 of 17 (2995 views)

GA_TRI_DAWG wrote:

3Aims wrote:

I'd use best bike splits website for IMTX course. It's pretty darn accurate if the winds are close (model vs actual). It will also give you an idea of how tinkering with your watts will impact your time.

Not sure I did it right but I put in 200 lbs on my profile and got back these results with my 2013 P3 and 404 front 808 rear. 20.96 would be nice lol but I don't know about that in reality. I certainly think 200 watts is easily doable. I also had 10 knots at 270 (which I think is coming from the west)

CourseIronman TexasDistance111.33 miTime 5 hours 18 mins 41 secs Avg. Speed20.96 mphAvg. Power196.01 wattsNormalized Power�198.85 wattsVariability Index1.01Intensity Factor�0.62Training Stress Score�205Watts/Kg2.22Avg. Yaw7.64 �BikeP3

I then changed my weight on the profile to 180 and updated the race and got:

CourseIronman TexasDistance111.33 miTime 5 hours 15 mins 42 secs Avg. Speed21.16 mphAvg. Power196.24 wattsNormalized Power�199.29 wattsVariability Index1.02Intensity Factor�0.62Training Stress Score�204Watts/Kg2.4Avg. Yaw7.55 �BikeP3

So a three minute savings? Sound right on a flat course?

Edit:

I used BBS to look back at 70.3 PR and it matched perfectly with my result. I had a 2:43:## bike split and BBS said:

CourseSan Juan 70.3Distance56.48 miTime 2 hours 43 mins 21 secs Avg. Speed20.74 mphAvg. Power195.01 wattsNormalized Power�197.30 wattsVariability Index1.01Intensity Factor�0.79Training Stress Score�170Watts/Kg2.17Avg. Yaw7.35 �BikeP3

So that makes me think the 200 watt goal is too high by a bit for IM TX.

Maybe 15 watt reduction?

Gives me a BBS target at IM TX of:

CourseIronman TexasDistance111.33 miTime 5 hours 29 mins 50 secs Avg. Speed20.25 mphAvg. Power181.90 wattsNormalized Power�184.41 wattsVariability Index1.01Intensity Factor�0.74Training Stress Score�300Watts/Kg2.03Avg. Yaw7.98 �BikeP3

I could easily live with that. :-)

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 10:53

Post #10 of 17 (2974 views)

you're thinking about this all wrong. you need to throw speed out the window. It's irrelevant. Just plan for a 5.5 to 5.75hr ride and control what you can control... the inputs. Speed (and therefore time) is an ouput and out of your control. You shouldn't even have a time or speed data field on your bike computer if you use one. They can't help you, and can only cause you to chase an arbitrary time goal and hurt your run.

control:

calories
fluids
electrolytes
effort
spikes in effort, ie. burning matches
pacing (by HR or power)
staying aero on bike
riding with slightly faster athletes at the legal distance
wearing aero clothing, making aero choices with bike equipment, using good tires and tubes
wearing sunscreen, staying cool

etc.

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Re: IM Bike pace target at new weight? [ericM40-44] [ In reply to ]

Mar 31, 15 11:11

Post #11 of 17 (2946 views)

ericM40-44 wrote:

I absolutely hear you :-) and I feel I have good idea on all the things you have listed there. The only thing I am doing different for this race is loosing an extra 15 lbs or so.

I will still pace based on my tried and true HR zone of 130 - 140 bpm. I was just looking for a way to see what the weight difference would be. Seem like it is very little for the bike on a flat course like IM TX. But I know it will be great for the run.

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 11:32

Post #12 of 17 (2919 views)

GA_TRI_DAWG wrote:

ericM40-44 wrote:

I absolutely hear you :-) and I feel I have good idea on all the things you have listed there. The only thing I am doing different for this race is loosing an extra 15 lbs or so.

I will still pace based on my tried and true HR zone of 130 - 140 bpm. I was just looking for a way to see what the weight difference would be. Seem like it is very little for the bike on a flat course like IM TX. But I know it will be great for the run.

Losing 15 lbs on a flat bike course in an aero position will not really produce any noticeable speed increase. Maybe .1 or .2 mph at the most.

----------------------------------------------------------------
my strava

Re: IM Bike pace target at new weight? [lschmidt] [ In reply to ]

Mar 31, 15 11:37

Post #13 of 17 (2908 views)

lschmidt wrote:

Losing 15 lbs on a flat bike course in an aero position will not really produce any noticeable speed increase. Maybe .1 or .2 mph at the most.

Yup that is what I am starting to figure out. Now to my next question.......Why do we pay so much for bike components that weight .02 oz less than cheaper ones lol.

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 12:09

Post #14 of 17 (2874 views)

you're weight loss isn't going to make that much of a difference on the bike. That courses favor p/CdA.

But on the run....well that's a different story.

IMO you're thinking about this whole thing incorrectly.

Brian Stover USAT LII
Accelerate3 Coaching
Insta

Re: IM Bike pace target at new weight? [desert dude] [ In reply to ]

Mar 31, 15 12:42

Post #15 of 17 (2842 views)

desert dude wrote:

you're weight loss isn't going to make that much of a difference on the bike. That courses favor p/CdA.

But on the run....well that's a different story.

IMO you're thinking about this whole thing incorrectly.

Oh I realize the big gains on the run and that is my real reason for losing the extra weight. I was just wondering about the bike aspect. The run benefits have been well documented in past threads. So while the initial question seems backwards its only because I didn't add points on what benefits I was expecting from my run.

Full disclosure: I walked/ran a 5:56:00 marathon at Louisville and I am losing the extra weight so I can properly train and run better at TX. I just wanted to see how it would impact my bike.

You could say that I over cooked the bike at Louisville but that is a different style course then TX and I was under training at 10 hrs a week. I am getting in my 13 to 15 hr weeks this time around. That extra time is resulting in a greater loss of weight. So better/more training = weight loss = faster run with my standard bike.

I'm not sure that clears it up or if you think I am still confused about things but no worries as my question as been answered. :-)

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 16:38

Post #16 of 17 (2734 views)

Also keep in mind that the prevailing winds in Houston that time of year are out of the south BUT they increase as the day goes on. In addition you have some tree cover on the way up and very little on the way south. All of that conspires to give you little advantage on the first half and a considerate, hot headwind on the back half. Also, the five or ten miles on 2920 feels like riding on the sun.

That said, it's still a blast!

Re: IM Bike pace target at new weight? [GA_TRI_DAWG] [ In reply to ]

Mar 31, 15 16:43

Post #17 of 17 (2728 views)

GA_TRI_DAWG wrote:

lschmidt wrote:

Losing 15 lbs on a flat bike course in an aero position will not really produce any noticeable speed increase. Maybe .1 or .2 mph at the most.

Yup that is what I am starting to figure out. Now to my next question.......Why do we pay so much for bike components that weight .02 oz less than cheaper ones lol.

Cuz people are idiots. See also compression gear and power cranks.

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