Correct, Also, make sure to check the crank length on them when switching bikes.

1. Weight alone? No. IMHO, weight impacts body shape and size (i.e. W/CdA) moreso than any W/kg. But plenty of big guys just tear up flat courses even on power like yours.
2. As others have said, fit/position, tires+tubes, and helmet are the first things that come to mind. Your fit (pic in post #14) isn't fantastically aerodynamic, even if it is technically correct. You are sitting back w/ hips rolled back on that saddle a bit-->pulls your torso up and arms back-->creates a parachute to slow you down. You're not small, so you do the best with what you got, and not everyone will get to CdA 0.19. But you can almost certainly do better.
Can't see which tires and tubes you have, but those can lose you alot, esp. if overinflated.
Others have weighed on the helmet & head position, and they're probably right.
Suit also is a possibility; though this one doesn't look too bad I have no idea how it tests, and you appear to have two that you use. Find the faster one.
And powermeter calibration--I wouldn't eliminate potential problems there, though I think they're unlikely.

Bottom line, I think your competition knew how to get more out of their bike than you. 25mph on 225 W is damn good. And there's lots of little things for you that will close the gap significantly. You'll get better, but you need to tinker a bit. -J

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Life is tough. But it's tougher when you're stupid. -John Wayne

Defensive, not at all, it's more interesting that you would only work with someone hands on for aerodynamics. Yet working with someone hands on got you a fit that is less aero than some road bike fits. Especially when there are lot us here doing this for a long time that know a lot.

From your fit it looks like you're sitting far back like someone else said which is causing you to not be able to get low in the front. However, the saddle is jammed pretty far forward and from what I can tell you have a short stem. It almost looks like you're on too big of a bike and the fitter solved the problem by compacting your position.

-Not having a disc wheel or disc cover is costing you 30-60 sec or so in a half.
-Your helmet is definitely not one of the better ones, depending on how bad it could be another minute.
-A bottle on the down tube is normally a negative.
-A BTA bottle is going to be more aero than one dropping down with a straw like in the first two pictures.
-I can't tell what aero bar that is to determine if it's a good one or not.
-Are you using latex tubes? What tires?
-Non-aero brakes are also costing time.

If you look at the pictures of who you're comparing yourself to he's full on decked out aero, sleeved Tri suit, catlike helmet with the vent closed, Tri rig brakes, disc wheel etc. All these small details make a huge difference.

So you come to slowtwitch asking for advice on how to get more efficient on the bike but you’re not interested in advice about your fit which is probably having the biggest impact on your efficiency? That makes no sense to me.

To add another data point, here's my data from Busselton 70.3 a few years ago using a powertap. I would have been no lighter than 170 at the time and on the bike in my profile. Wasn't that fit at the time, hence the low IF.



ETA: I'd managed to drop the aerobars another 1-2 cm between the time that photo in my profile was taken and the 70.3.

I may have misspoke or things didn't get communicated correctly so that's probably my fault. I've got great advice about what I can do to improve but what I meant is that no one on here is going to be able to tell me through a forum exactly how much to move my seat up down forward or back or how much to move my aerobars. Also things like the down tube bottle could save time I know that but it's a preference so I know I have all the fuel I need and don't rely on aid stations. I'm here for the great tips I've received. Last year this time I was 230 lbs and didn't own a tri bike so it's all new to me and I'm grateful for all the knowledge given to me.

Thank you for your input.

I did a calibration on the pedals tonight and did a short ride after the warmup and spin down on the Kickr. I kept it in ErG mode and let the resistance be controlled by the Kickr. I also started my 920XT at the same time as the Wahoo App on my phone. At lower power (150w) the Kickr obviously showed 150 exactly but the Vectors showed 133. At 210 for the Kickr the Vectors showed 207 and at 300 the Vectors showed 299 so I'd say that are good to go. The Kickr is brand new and V2 so I trust that and both showed the same for average to higher power numbers. I've been told by Wahoo that it will vary more at lower wattages.

So time to get more aero! I was staring to get worried the power meter has been giving me false readings all this time.

So to backtrack. Do y'all keep separate FTP settings for indoor and outdoor? Two weeks ago my outdoor ride showed a 20 minute average power of 313 for a hill I climbed with some rolling ones included (266 avg for the 2 hr ride w 2650 elevation gain, 298 NP) but I did another indoor trainer road FTP test last week and could only manage 272 for the 20 minute test as average.

It also seems that the hillier the ride the more power I have but I can't maintain those high power wattages unless there are hills. On the flats I just can't keep the power as high (which I rarely have that opportunity). Is it an issue or just how it works from hilly to flat courses?

Thanks again for your help I know I'm a pain in the butt.

So first, are you recording zeros? Because that will inflate your outdoor numbers. Same thing with auto pause.

My understanding is that average power includes zeros such as coasting but NP compensates for this hence why NP is usually the same as average power indoors and different outdoors when there is a hilly course. None of my numbers listed except the one include NP.

Explain what you mean about auto pause causing an issue.

Not exactly. Normalized power approximates what power you could have biked if your VI was exactly one. If you live somewhere flat NP and AP are generally pretty close. I'm in Colorado they are never that close it's just not really possible.

What he meant with zeros in AP is that you can remove them in Garmin settings. It will inflate your numbers though because you're not including those in the average. It's technically the same thing with auto pause although I keep that one on since if I'm doing intervals or something I'm not stoping at a stop light and recoverying between them. From my perspective easy riding isn't that much harder than stoping at a light for 2 mins so it's not really throwing my numbers off.

In general, drafting could account or contribute to the discrepancy. Just sayin'

Never!!!

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Genetics load the gun, lifestyle pulls the trigger.

describe the fan set up you utilize indoors, it matters, a lot , if you cant cause yourself to suffer without cooling. I used to not use much if any fan, could still produce same indoor vs outdoors, but would be very warm and in a pool within 5 min. since I went to a more powerful fan, I no longer desire to ride indoors without it. just feels so much better such that when my dogs stop between it and I, I tell them to move, now! some folks have a hard time without the fan and it cant be a scrawny ass box window fan, they put out nothing

Unlikely in this case the guy he is talking about got second in the race overall and had like the 30th fastest bike split.

When you're going 23.5+ for a half there's really not many people you could draft off of unless it's worlds or nationals type races. Slingshot sure, I do that all the time but legit drafting is hard.

It's all about bike setup and position if you look at the OP he has an average bike setup with an average position, typical age grouper set up. If you look at the pictures from the race of the other guy, it's a full aero setup with a very aero position. It makes a huge difference.

I'm a big fan of the above graph (not mine originally) for understanding just how important CdA is to speed and for doing some CdA sanity checks. I know there are a bunch of assumptions in that graph that don't quite match (like flat course), but it will still be in the right ballpark to check reasonableness.

-) Your competitor did ~40km/h. So he is on the 1000w/m^2 curve, meaning their CdA is roughly .23m^2 at 230w
-) You did ~35km/h avg. That puts you roughly on the 700w/m^2 curve, meaning your CdA is roughly .37m^2 at 257w.

Very slippery TTers will usually have CdA values between say .19 and .21. .23 is not bad for a position that can be held in a half triathlon. .37m^2 on the other hand is in the range of "poor road position". So what could explain that:

1.) As you first point out, a power meter reading high will throw this off, but sounds like you did some double checking.
2.) The Crr assumption of the above graph could be off. To get the .45 Crr, you really need to be rolling very fast tires and latex tubes. Throw on slow tires like gatorskins and butyl and all bets are off.
3.) Your position/setup could be that bad aerodynamically. Your head does look very high in the pictures you posted. You don't have a disk, your water bottle is not that great, etc. To get down to <.23CdA, you really need to be attentive to details, getting lots of little things right.

you should probably be using their avg powers and not NPs NP is imaginary power as far as W/m^2

the double checking of his PM was against a Kickr 2 which is not really any kind of check. just fancy hand waving

as I said in earlier post, my upright not caring about aero road position is about where he is falling which seems wrong based on photos. I still vote for PM being off or brakes stuck or really bad tires/tubes or any combination of those aside form head and helmet selection

I never really like NP anyway seems like a fake number to me.

And I assume from your comment that you don't like the Kickr or trust the accuracy, but let's say both the Kickr and the Vectors and inaccurate...what's the chance that they are inaccurate exactly the same? I highly doubt that to be the case so I would trust the numbers, but I'm sure you might have a more detailed description of why this can't be. I don't have access to another power meter enough to put it on my bike and test it against the others so I'll just have to trust it, but I'm leaning towards my aerodynamic inefficiencies as the big factor here which is exciting b/c I can certainly improve those things before my next race on May 21st.

the odds of being off exactly the same are about the same as the odds of both being correct and the same :) you cant checks something by using an unknown and the kickr will be an unknown unless you have a way to calibrate it at home.

as your set up does not pass the eyeball o.35CdA requirement, something else must be off but you still haven listed all of your equipment choices have you? idr

i't say you are probably in the 0.285CdA area based on above pics

You are probably right regarding AP vs. NP, but I don't think that changes the rough numbers and sanity checks.


Not sure about kickr 2, but I well know that the original kickr is all over the place. Had all kinds of issues making mine "match" my two quarqs (which also matched my powertap), so no doubt his power #s are still a bit suspect. Been "racing" on zwift a lot where it has become pretty obvious that a sizable fraction of people have power meters that read funny.

Agreed on the bloated #s. My usual road position backs into ~.27m^2 CdA, so I am not sure how someone gets >.35 on a TT bike without something being way off.

The kickr is reading downstream from the pedals it should be a different number they shouldn't be the same. If the kickr is right it does mean your powermeter is most likely reading low.

NP isn't a fake number if you are using it correctly. It's actually very useful, but you have to understand it.

I'd say a 0.27 CdA on road bike is an in the drops elbows at 90deg position :) not something you want to ride for hours, at least not me, as triceps might get a bit tired(or maybe that was just me before all my recent core work to reduce back pain)

re head position, what exactly are you trying to see by cranking head up as high as is seen in your pics? the moon, fluffy clouds? <= that might seem harsh, but your head does not need to be that high to see 1/4mi up the road and it is going to be causing a boatload of drag(most likely)

Doesn't that mean there were 29 guys he "could have" drafted? Again, not sayin' this individual did...

Sure but it becomes really hard at the pointy end on a wave start. The top bikers just really end up spread out around the course.

I'm not a great swimmer but normally bike 23-25 mph at tris. I don't remember a race where I really an opportunity that I could have drafted minus nationals/worlds. You're normally slingshoting like crazy cause you have everyone and their mother from previous waves that you have to go around. But finding someone who can ride that speed and came out of the water around you is really a stretch.

Also, the watts aren't that surprising for someone in decked out aerogear like a lot of people have said. I did Florida 70.3 a few years ago at 200 watts and did 23.4 mph on the p4 setup in my profile. At 230 watts I'd probabaly be sitting right where that guy was give or take.

Agree on all points. Grant's experience squares almost exactly with my race data from this race (I think OP confirmed it was Steelhead). I rode 200 AP/217 NP and averaged 23.6. There was no chance for me to draft at really any point during the 56 miles, even if I had wanted to (in fact, I had to deal with a fair bit of (unintentional) blocking leading to my high NP, as I had to slow/accelerate a fair bit) but I would say the slingshot factor was significant as I literally passed hundreds of riders, since I was in M40-44.