He's using them the way anyone who remembered chemistry, or engineering, or statistics, or any of a large number of other fields that require measurement and evaluation would use them. How about this: go to google.com, type in "accuracy" and "precision" and click on "I'm feeling lucky."

Oh, btw, I almost forgot: you know how you were pointing at little bits from the title page and page 3 of that thing? One of the studies that says that field testing can produce results comparable to a wind tunnel is listed on the page between those two.

Coincidentally, on the first day of my 10th grade chemistry class the teacher showed us a couple pictures of bullseyes not unlike the two found on a certain wikipedia page. We discussed accuracy and precision for a couple minutes and somehow it stuck with me since way back then.

One quick search with the googles turned up the wikipedia page... now that wasn't too difficult to find.

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Erik
Strava

Very simply. Measurements.

I have diagrams of "stack and reach" to all the touchpoints for both my road and TT positions. This case was easy because I had the P2K to measure off of right next to the P3C.

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http://bikeblather.blogspot.com/

sounds solid once the density was equalized. Hopefully conditions for the upcoming TT are amenable to getting another solid CdA reference. Oh yeah, hope you go fast too ;-)

Sure, as long as you realize that it is just a rule-of-thumb arrived at via some rounding, whose purpose is to simplify doing calculations in your head.

How is the bottle cage attached to the aero bar? Do you really keep water in it?

Thanks,
Scott

which bike had powercranks,insert smilley face,been tting for twenty years saw a lot of wheel covers in the beginning,now see a lot of discs deep dish etc, see a lot of Crevelos, never see a round tubed steel bike,at one time got a disc that would make me faster,,,,the one thing i do not see is people going faster,the times for everyone should have dropped over the years with all of this equipent to make you go faster,everyone should be doing 48 minute 40ks if this stuff worked

Zip-tied to one extension with bar tape under it for better "grip".


Absolutely. Perhaps not completely full during a race, but at least enough to "wet my whistle" midway through a 40K TT.

It also works out good for the event that pic was taken from, which is a local monthly 10 mile TT that I ride to from my house. Since the start and finish are at 2 different locations, this allows me to take along some water for my warmup without having to worry about retrieving a bottle at the end.

Note the seatbag with tire repair supplies as well for the same reason ;-)

BTW, I haven't formally "Chung'd" this bottle location yet. In fact, it was left off during the testing vs. the P3C and I'm not planning on putting it on the P3C for the race. That said, I have no indication that this bottle location is any slower (or faster) for me than no bottle.

edit: If my arm position was flatter, I most likely would have the bottle mounted above the extensions instead of below...just thought I'd add that.

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http://bikeblather.blogspot.com/

If I could make as much power as I could ~20 y ago, I'd be under 50 min even at sea level. As it is, I'm still several minutes faster now than I was, say, in the mid 1980s (when aero wheels, aero bars, skinsuits, etc., first became popular), despite a ~20% reduction in my power output.

I know your background,i know the aero stuff can work,but with every product saying you go 2 minutes faster in a 40k,i do not see the whole as a group at states tt going faster then twenty years ago.Better bikes better training,but the times about the same, Has anyone beat John Frey's tt time from around the late 80's?.
I know your Old bike (Hooker) to your new bike is not as a aero difference as some of us has had,(round steel to Aero), I just can not wrap my head around a lot of the aero claims

1. You don't think that somebody like Dave Z could take that record if they wanted to?

2. People don't take TTing nearly as seriously as they used to. For example, back in the mid 1970s it wasn't uncommon for Wayne and Dale Stetina and Tom Doughty (all Olympians) to contest our state (district) TT. Nowadays, most cat. 1 riders don't even bother to show up, preferring instead to find a mass start race or just train instead.

1 really not sure
2 been seeing the same guys for years,after a 10 year absence of not doing our state i was supprised to see a lot of the same people,better bikes, about the same times (plus new people) I do think your right about not taking TTing seriously we would have twenty people at a Thursday night TT then nobody now 4 or 5 of us get together once a month

Well duh: like me, they're apparently attempting to delude themselves that they aren't getting older by continuously upgrading their equipment. ;-)

You know those ROTs? You need to add another sorta like: $X is roughly equivalent to 0.5 s/km.

So if you don't have a "loop" course, can you get the same results by "repeating" a particular stretch of road (in the same direction, cruising back to the "start" each time)? Post test you would delete all of the "cruising" data and be left with only the "laps". Granted, they're not starting/ending at the same elevation (nothing here in Colorado does), but if you have accurate altitude data over the stretch of road, will this method still work well?

Sorry if the answer is clear when you study the paper...I thought asking would be quicker than reading/studying. :-)

Well i sure have done the upgrade thing ,i guess my brain can not understand,i got slower and older,so i should sell all of my new go fast stuff,get back on the first TT bike i ever built(not assembled,built brazed tubed kind of built)and just enjoy myself

because outside of a stage race, they don't count for upgrade points...

:/

g

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greg
www.wattagetraining.com

better read the paper, then re-read the paper, ....

If you don't fully understand the basics - any shortcuts are likely to lead to some ugly dead-ends !

I think the presentation suggests a half-pipe like the one Tom uses but there's actually a fair amount of flexibility. You can use loops or laps or an out-and-back or, in fact, any segment where you happen to know the true net elevation gain: I've actually used repeats on a stretch of road exactly in the way you're asking about. The loops and laps are because we know the true elevation gain nets to zero. If you do decide to use an out-and-back course it's probably a good idea to do at least a couple of laps at different speeds. Winds are always an issue so this approach lets you focus on finding a venue that helps you minimize wind effects without also having to find one with constant slope. It's actually good not to have a course that's too flat.

The bottom line is, this approach isn't magic -- it just means you can expand the places where you could test and puts the onus on you to take good measurements.

robert,
speaking of non-ideal venues, what is your take on the "smart guys" approach of neutralizing the VE of an unavoidable (flat) braking zone by setting the VE for each record in the entire zone to that of the entry point. IOW, flattening that portion of the loop.

Better brake relatively hard and correct for it vs. raising your head, sticking out the knee ... bleeding off speed in an less obvious way?

Uhm, I'm assuming the braking zone will be short in relation to the length of the lap - otherwise - 'tis obviously not going to work too well ;-)

:-)

There's a physician/popular author/radio personality out in California (whose name I can't remember), and in one of his books he provides advice for aging men who still want to remain competitive in sports (I was sent a courtesy copy after answering a few questions for one his editorial assistants...don't have it any more, though). One thing he suggested was getting into new sports before they became really popular (his example was inline skating), and started attracting athletes better than yourself. Another piece of advice, however, was to use your wallet, i.e., to outspend younger men on coaching, equipment, etc.

Thanks. Since someone has said that the technique is "just as accurate" and "nearly as precise" this implies these terms have been quantified for the approach. What is the standard deviation of the technique that would define "precision"? Would the standard deviation depend upon the accuracy or the precision of the power meter? wikipedia also stated this as regards precision.

What is the repeatability an reproducibility of the technique? I am mostly interested in reproducibility as that seems to be the major flaw in the technique for general use, since good results require great attention to detail.
This looks like it might be a great technique for individuals to assess how changes might affect them overall. Are they better or worse off for the change and by approximately how much. However, I can't see it as being particularly useful in comparing the aerodynamics of two bicycles, as was seemingly done here. Was the person doing the test blinded to the bicycles? Was the person evaluating the test blinded to the bicycles? How do we know the head was held the same the entirety of the two runs? Or, a myriad of other potential "problems"? However, if they feel what they are doing is aerodynamically advantageous (whether it actually is or not), this could help them psychologically. So, where is the racing benefit coming from?

Further, was a mistake made in the original calculations, in that the air density was not properly accounted for between the two runs? It would appear that a great deal of attention to detail must be applied here for this to be the least bit accurate, even for the overall number. I haven't quite figured out if this "error" refers to the original post or to a post on another site. Either way, it is one of those "detail" things that can greatly affect the results, which goes go my point.

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Frank,
An original Ironman and the Inventor of PowerCranks

Attorney: "Objection, Your Honor! Asked and answered."

Judge: "Agreed. Move on, Mr. Day."

Hmmm. I've thought a tiny bit about this but not a lot. If this is an out-and-back and you're talking about a turnaround at mid-point, I'd tend to think there isn't much of a problem: the braking and re-acceleration out of the turn gets picked up and you just have to match up the start/finish. If this is a loop course with a lot of turns, and one of the turns is one where you have to brake, then it's slightly harder: basically, I've split the file into segments ending on the turn and matched up the segments. That might be equivalent to what you're suggesting and it's a pain. BTW, that's one of the reasons why I try not to fit on VE peaks. I always begin by doing the VE plots but I don't always end there.