Getting slippery on the bike

aerofan

New to this forum - not the strongest rider so being aero is a big factor in my performance. Ideal conditions in the next few days to do some aero testing, so I'll be out on my TT bike with my Garmin collecting some power and speed data to analyse. My Cda on the TT bike is usually around 0.1900. Road bike it's 0.2900. There is a lot of scope to improve my road position and equipment (!)

RChung

madasahattersley wrote:

What sort of size are you/have you been in the wind tunnel? I'm no expert but 0.19 on the TT bike doesn't sound too spectacular, no offence

You're no expert. No offence.

RChung

I think it's remarkable to admit that one's opinion is worthless yet persist in sharing it anyway. That shows far more self-confidence than most of us possess. I'll try to remember that of you. No offence.

meanredspider

RChung wrote:

I think it's remarkable to admit that one's opinion is worthless yet persist in sharing it anyway. That shows far more self-confidence than most of us possess. I'll try to remember that of you. No offence.

Let's face it - it's far better than posting your opinion not realising that it's worthless....No offence.

ETA - typical Road thread :roll:

RChung

meanredspider wrote:

Let's face it - it's far better than posting your opinion not realising that it's worthless....No offence.

None taken. But, ah yes, I recall you're an example for Dunning-Kruger?

Nonetheless, it seems like a couple of you have taken offence at my posts, even though, like you, I specified "no offence." Perhaps that phrase isn't as effective as some might hope, and one can't really get away with saying offensive things simply by stating "no offence." Something to think about.

meanredspider

RChung wrote:

But, ah yes, I recall you're an example for Dunning-Kruger?

The irony of you writing this isn't lost on me.

madasahattersley wrote:

Priceless! Trolling of the highest calibre.

Yup - if there's an expert in anything on this thread, you've nailed it So few posts and pretty much every one barbed.

Apologies, OP - thread totally derailed.

bahzob

Back to OP, assuming he/she is still there...

I think 0.19 is pretty good Cda. I thought even the now banned superman/Obree positions were not that good.

One goal for winter is to work on aero position so be interested in seeing some pictures of it for comparison. Also like to know how Cda was calculated.

Mikey23

i was curiously drawn to the title...

RChung

bahzob wrote:

Back to OP, assuming he/she is still there...
I think 0.19 is pretty good Cda. I thought even the now banned superman/Obree positions were not that good.

Yes, it's unusually, exceptionally low. I've had a chance to measure the CdA of a couple of hundred riders now, and I've only seen a (verified, zero yaw) CdA for a UCI-legal road TT position that low twice. Both of those times it was for someone who had spent a fair amount of time and effort tuning their position and equipment. So I'd put 0.19 at a very unusual level even among elite riders. The OP's road bike CdA of 0.29 is also on the low side, but not quite so unusually exceptionally so. I would think that either the OP has unusual morphology or else the estimates are suspect.

The Superman can be below 0.19, but not a lot below (at least, for a rider of "usual" size with "usual" morphology).

Mad and Spider don't even know what they don't know. No offence. OTOH, if you're of mind to, google up "Chung CdA".

meanredspider

RChung wrote:

Mad and Spider don't even know what they don't know. No offence. OTOH, if you're of mind to, google up "Chung CdA".

I don't claim to know anything about the drag coefficients of cyclists. What I do know, though, is that of the few posts I've seen from you, you come across as an arrogant troll - maybe that's just an unfortunate part of your personality or writing style. Causing offence seems like a hobby.

bahzob

Making another desperate but probably futile attempt to drag this post back to the OP .

To OP: If you are still out there please can you post a picture of your position. It certainly seems to be exceptional.

To RChung: Ditto, if you have any examples of the 0.19 or close riders could you share them please. Also be interested if you have a summary of the measures you have done so far, maybe broken down by rider height, to get a feel for what it is realistic to aim for. (I plan on using your method + Golden Cheetah as basis for measuring)

RChung

meanredspider wrote:

RChung wrote:

But, ah yes, I recall you're an example for Dunning-Kruger?

The irony of you writing this isn't lost on me.

Evidently, it was. And that's why you're the perfect example of Dunning-Kruger. You know that old saying, "Give a man a fish and he eats for a day but teach him how to fish ...." ? In this case, the fish is information. If I'd simply said "no, a CdA of 0.19 is exceptionally low," that would be giving someone a fish. But pointing out that you don't know what you're talking about but your opinion of yourself is so high that you figure no one else on an internet forum could possibly know anything more than you either is teaching the world something that will be useful for a lifetime.

Bahzob, there's a thread at the very top of this forum that has photos of TT positions. One of the interesting things I've learned from examining a large number of riders is that the eye is a poor measuring device. You can get into the right ballpark by looking at photos but at most the eye can see the "A" part of "CdA" (and most photos are taken from the side so you can't really see "A" anyway). So the eye can get you close but when you're really trying to optimize equipment and position you need to use more precise techniques. Aerolab is a handy tool but you still have to be careful with the test protocols. Think of it sort of like Microsoft Excel or some other spreadsheet software -- it will do the calculations for you but you need to put in the right data and formulas in the right places.

frisbee

OP just decapitate yourself, it'll reduce your frontal area and, even better, you won't have to read this thread anymore!

liversedge

For those that don't know RChung is the inventor of Virtual Elevation, a technique for establishing your CdA using a field test and a power meter. Its been implemented in GoldenCheetah as 'Aerolab'.

Also, for the record, 0.19 as a CdA, as an cursory glance on the internet is a pretty bloody good value -- whether its right or not is open to debate though.

It might be best to go and do the smallest amount of homework before offering opinions.. and also since you have Dr Chung's attention you should exploit it with some good questions !

Anyway, gonna crawl back under my rock now.

Mark

imposter2.0

liversedge wrote:

For those that don't know RChung is the inventor of Virtual Elevation, a technique for establishing your CdA using a field test and a power meter.

His interpersonal skills need some work though.

liversedge

Imposter wrote:

liversedge wrote:

For those that don't know RChung is the inventor of Virtual Elevation, a technique for establishing your CdA using a field test and a power meter.

His interpersonal skills need some work though.

Not really. Someone posted the most ludicrously ill-informed nonsense and said 'but I'm no expert'.
He just pointed out how utterly clueless the poster was and really if you are so clueless you should just STFU.
So many folks feel they should contribute to a discussion when they have no idea what they are talking about, and as a result everyone gets confused and we decend into these meta discussions as a result.

Mark

imposter2.0

There are better ways of saying things. We have other professionals posting on this forum who manage to get their points across with much more diplomacy than that. But anyway, let's move on...

bahzob

RChung wrote:

Bahzob, there's a thread at the very top of this forum that has photos of TT positions. One of the interesting things I've learned from examining a large number of riders is that the eye is a poor measuring device. You can get into the right ballpark by looking at photos but at most the eye can see the "A" part of "CdA" (and most photos are taken from the side so you can't really see "A" anyway). So the eye can get you close but when you're really trying to optimize equipment and position you need to use more precise techniques. Aerolab is a handy tool but you still have to be careful with the test protocols. Think of it sort of like Microsoft Excel or some other spreadsheet software -- it will do the calculations for you but you need to put in the right data and formulas in the right places.

OK.

RChung

liversedge wrote:

Virtual Elevation, a technique for establishing your CdA using a field test and a power meter. Its been implemented in GoldenCheetah as 'Aerolab'.

Here's a little recent testimonial about the effectiveness of GC's Aerolab. Note the guy says his power is down from last year but his aero drag went down even more.
https://www.youtube.com/watch?v=TeMbxouIS4g

Joeblack

Haha I think it's fair to say some people on this thread have been owned, take it like a man, it's ok not to know jack about a given subject.

As previously said, be grateful someone who does know what their talking about is talking and listen.