That's because Starky had that aero-as-barndoor hydration setup between his bars. If he'd only listened to wsrobert he could have split the same on 340...

Are you talking at Kona or at Florida?

Seems I read that the Torhans30 tests faster than no bottle at all and faster than a BTA bottle.

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-Andrew

Input does equal output at the front of the race - for the most part. Or if you're at least riding through everyone and not sitting in the draft packs.

Also...15 watts from powertap to crank based? Nadda. Unless you're rolling with an ungreased/terribly dirty/grimy chain.

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"One Line Robert"

Sorry, I was kidding. But I mean this one

Ray says 5-15W. Roughly 15W was the delta for me when testing my PowerTap against my Quarq. I've heard this figure elsewhere, but yes it varies. Notice I said maybe

My gf was running a pt and srm for a bit before kona, and it was about 3-3.3% different. So at 300 watts... that's almost a 10w difference.

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Not only that, but he's obviously using a heart rate monitor there. That had to have held him back as well...

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-Andrew

The difference between a powertap and a quarq will not be a constant number, but most closely simply a percentage of power at that point in time. 5% diffference is probably reasonable. Things like a dirty drivetrain or bent derailleur hangers will make this difference greater.

Good take. 4-5% was the difference I observed personally.

I've also ridden that split on a lot less watts, but also way slower on way more watts... so I don't think that's a great metric between courses.

Keep in mind Josh was out there an hour after the pros and almost 30 minutes after the top ager's, and was riding alone. The wind definitely picked up as the day went on, and the front of the ag field had some massive peletons. I was at the turn at mile ~45/75 and my brain exploded at how big some of the groups were. Only saw a few marshalls go by and they seemed to be further back, or stopped on the side of the road drinking coffee for 30 minutes (true story).

Didn't Rapp also say that the difference between the Mcclaren helmet and aero road helmet was 15 watts? Josh was wearing a regular road helmet, so that's gotta be a few more watts.. Add in a slightly upright position, and the fact that he probably wasn't turtling much bc he had to watch out for people going 50% slower than him, and it's not hard to believe it took that much wattage to go that fast.

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Twitter | Kancman | Blog

The difference between a powertap and a quarq will not be a constant number, but most closely simply a percentage of power at that point in time. 5% diffference is probably reasonable.

When this has been tested in the lab, drivetrain losses are closer to a fixed wattage for the range you are interested in (like 150-500W). And it is ~8W if your gear is in good condition.

I am not doubting that his power meter said 317 watts or so at Kona and 324 watts at IMLP or that he is not capable of riding that many watts.

I'm simply stating that 317 watts is a *shit* load of watts, and that *many* other people have ridden faster, sometimes significantly so, on a significant number of fewer watts.

That suggests that either his power meter is defective, or that he has a lot of speed to be gained by tweaking small things - one of which, as you mentioned is to use an aero helmet.

And get rid of the bell he has on his aerobars to let people know a freight train is coming.

No need. I fully understand the differences in wattage different courses and different days on the same course can cause - though I will agree with bill - generally speaking power is an exceptionally good predictor of performance.

As I told snackchair, I'm not some hack who simply wishes his FTP was equal to Josh Becks IM power, so therefore thinks it is impossible for someone to ride an Ironman at that power. As I told snackchair, I fully believe that it's possible Josh rode that wattage, and that Andy Potts also rode your proposed wattage.

In reality, I'm a moderately fast and intelligent guy, who wishes his FTP was equal to Josh Becks IM power, and believes Josh Beck could have rode frighteningly fast if he simply paid attention to some of the aero details I have to pay attention to in order to remain competitive.

Bike
Position
helmet
Etc.

No way - that is totally badass.

it's not hard to believe it took that much wattage to go that fast.

I ballpark a CdA of ~.325 for him. I'm nearly as big as he is and that is my CdA on the road bike, with nothing aero at all. On the TT bike with old equipment, my CdA is ~.22. Granted I don't do Ironmans, but still... .25 should be possible while still being comfortable.

Hypothetically, if he could ride Kona with a CdA of .25 he would have gone ~4:09 on the same power.

There are a lot of people at Kona who spend little time and attention to getting aero dialed... pros even.

That alone tells me your estimates must be off, since no one has come close to that.

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Twitter | Kancman | Blog

Perhaps because no one with that sort of a setup has ridden 320 watts at Kona?

I agree. Josh is a monster, but he's not the best there's ever been, so if numbers are saying he should be then some numbers are off.

Josh rode pro peloton for a few years before opting out of that lifestyle. Josh regularly races Powerman Zofingen where he does well, but one Vansteelant or another blows his doors off on both bike and run. Josh is a monster who could certainly benefit from spending time on the aero and equipment details, but any numbers that indicate he'd set a course record at Kona are off.

Wait people are interesting in power less than 500w?

Interesting, because there would be fixed wattage losses, like the derailleur pulleys (well those would also depend on chain speed). I guess that explains partly about why different lubricants can make a real difference, since they would not affect the component that is a % of power that much, but could make a bigger difference on some of these fixed losses.

That alone tells me your estimates must be off, since no one has come close to that.

Estimate of what?

dunno - the data for Torbjorn's former course record is public, I'm not sure if Lieto's 2011 ride is, but if you poke around SRMs website there are hints that suggest that Normann's 2006 ride was in the ballpark of Josh's ride - wattage wise.

I would say thats less true now than it was just a few years ago. And might be more true of the womens field. But the men at the FOP seem to be listening...

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"One Line Robert"

I have tested 2 different powertaps vs 2 different cranks (SRM, QUARQ), on the road @ ~250 watts (all properly calibrated and zeroed).
In both cases, the crank-based watts were 2-3 watts higher.

Wow, 2-3 watts seems pretty good. I thought it was in the range of 5-8. But this also reminds of why Mirinda Carfrae has a big penalty vs. Caroline Steffen. Mirinda has to put out the exact same watts to overcome her drivetrain, and she has to put out the he exact same watts to turn her 700 wheels at 36 kph. The watts to overcome her drivetrain and the watts to overcome the wheels are a higher percentage of her overall brute power output. Definitely pays to be a bigger rider in Kona where watts per kilo are not that big deal and where brute top line watts matter more. The run is a different story though!