I am new to power and just acquired my first Powertap. I did my first light spin on it tonight before a loose crank forced me to stop spinning. Anyway, looking for a quick answer from those of you who know and can give a quick answer. I am 5’8", 155lbs. I have ridden 18 and 18.8mph average in my last two IMLP finishes. Wondering what I would have to hold for an average wattage to sustain a 20+ mph average over my next IM bike leg attempt. Thanks for any insight.
Probably just under 200w.
225-250. Obviously depending on position, wheel choice, etc. If you have great position probably around 230. You have bad positioning bump it closer to 250. Aerodynamics will play a huge part in this.
Way lower. With 230 watts I could bike a hair under 4:40 on a flat course, while checking almost all of the aero/crr boxes.
Good call, this was a quick guess on my end.
Position isn’t too bad. Running a fit by Ian at Fitwerx. Back is fairly flat. I stay aero for 75-85% of ride, and sit up on the inclines mostly. I ride a Kestrel Airfoil w/ Zipp 808’s, Zipp Vuka bar, straight extensions, and am going to try a Zipp Chrono crankset this year (not that these little components probably help me much). I also wear either a Rudy Project Aero or LG with windscreen.
You can try playing with the (many) inputs here:
http://www.analyticcycling.com/ForcesPower_Page.html
It could be anywhere from 150 watts to 300 watts depending on the course profile, road condition, your position, bike, etc…
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You can try playing with the (many) inputs here:
http://www.analyticcycling.com/ForcesPower_Page.html
It could be anywhere from 150 watts to 300 watts depending on the course profile, road condition, your position, bike, etc…
Thanks, I’ll try this. Trying to figure out what I should be sustaining for my easy trainer rides this winter before ramping up.
Just checked my IM Frankfurt file, I did 5:30 averaging 177w. I weigh 160lbs, height 5’10".
That’s exactly where I want to be, 5:30 or below! Good number to keep in the memory bank!
The only other thing I’d add is your question includes the phrase “… for IM”. Keep in mind all else equal the same watts gives you the same speed regardless of distance/time. Whether it’s a watt output you can maintain for 5+ hours is another question all together 
Ok, I did this today…and you can too! Ride about a 30 minute warmup. Interlace some short intervals to bring the hr up. Then for 20 minutes go as hard as you absolutely can, it’s called an ftp test and will basically be able to be plugged into the power agent software and tell you where to train at power wise. I retest about every 3-4 months. If the more iron specific athletes think a long test is better then please let him know, I have no experience going long.
It’s not really “wrong” per se, it’s just that questions like the OP’s can be answered “correctly” by a huge spectrum of wattages. For some it might be 260. For others it might be 190. The OP also just said “20+ mph.” A lot of mphs fall under that category ha.
I rode 5:13 in AZ on 176 NP. I need to look through my Joule to see if I have it adding in zero watts. My last lap was crowded and had a lot of coasting. My first lap was 193 NP for 22.5 mph. Overall was 21.3 mph. I am taller than you, 6’1 but weigh the same, 155.
I would say look at tires, helmet, and how much time you stay in the aero position. AZ also has super smooth roads which help.
It should have been quicker, but it was very cold and wet. The second lap had a headwind towards the end and I also lost some time to a crash! So not my best ride!!
I truly appreciate all the comments and input
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I did a 5:23 on 157 watts at IM Texas. I raced at about 157 lbs and I’m 5’9.
Train for your current fitness level, not for where you think you should be in your future race.
IM courses are littered with the carcasses of people shooting for a particular time or pace. You need to be dialing in the effort (ie watts) you can sustain for the duration of the bike.
The distance does not matter when trying to figure out what speed you will get out of XXX watts.
what were you watts for 18.8mph?
if you knew that you could get a pretty exact answer
otherwise the answer is somewhere between 100 and 300
I averaged 211 watts and did the bike leg in 5:07 in my first iron-distance this year at B2B. I was hoping to be closer to 225-230 watts at well under 5:00, but the weather was far from ideal and impacted everyone in the race.