Author Topic: Critique my aero position  (Read 8458 times)

andygates

  • Peroxide Viking
Critique my aero position
« on: July 15, 2008, 08:58:29 pm »
Took advantage of the Plan's declared "aero turbo" day to shoot a little video of my current setup.  This video is with me well warmed-up, at a sustainable-stiff effort.

I always feel like I'm bouncing around a bit on the aero bars, but I'm not sure what to do about that.

Comments welcome!

<a href="http://www.youtube.com/v/vjB43BAwQ8M&rel=1" target="_blank">http://www.youtube.com/v/vjB43BAwQ8M&rel=1</a>
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Re: Critique my aero position
« Reply #1 on: July 15, 2008, 09:00:37 pm »
Andy,

You seem very high up. Is this for comfort (e.g. a long distance ride)? I'd say that if you could lower the front, stretch a bit, move toward the saddle nose, you would be much more aero.
Frenchie - Train à Grande Vitesse

Re: Critique my aero position
« Reply #2 on: July 15, 2008, 09:42:40 pm »
Andy,

You seem very high up. Is this for comfort (e.g. a long distance ride)? I'd say that if you could lower the front, stretch a bit, move toward the saddle nose, you would be much more aero.

+1
It looks like a good position for a 24hr, or maybe even a 12.
Maybe drop the handlebars and aim for a flat back. May need to move the bars forwards a bit too if you drop the bars. Also, maybe bring your arms closer together? I don't do short distance TT so you might not want to take much notice of what I say. For tri bars, you may find it better to use low pro bars. You have to set your bars lower for tri bars to account for the tri bar pads above the handlebars, but it means that your drop handlebar postion is too low if you're not in the tri bars. Using the brake hoods when your handlebars are set for tri bars is like using the hooks of your handlebars.
Depends on how much you are not in the tri bars I suppose.

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #3 on: July 15, 2008, 09:49:43 pm »
The height is mostly because I have pretty lousy back flexibility and that's as far down as I can get without something going sproing! 

Elsewhere have suggested that the bouncing is 'cos of a too-high saddle. 
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

David Martin

  • Thats Dr Oi You thankyouverymuch
Re: Critique my aero position
« Reply #4 on: July 15, 2008, 09:53:27 pm »
It's about rotating th ehips to get a flat back, not about bending over more.

I shoved the saddle forward, right to the limit of permitted, and it made a big difference. Then again I couldn't stay on the tri bars until I sorted the position.

Shove the saddle forward, drop the bars, lengthen the stem to compensate.

..d
"By creating we think. By living we learn" - Patrick Geddes

Re: Critique my aero position
« Reply #5 on: July 15, 2008, 09:57:40 pm »
I think the place to start is your saddle position, your pedalling action is very choppy, your bum is rolling around on the saddle and your toes are reaching for the pedals at the bottom of the pedal stroke all of which indicates that your saddle is too high.

Have a look at this bloke (that was linked to your video) he has a very smooth pedalling action and an almost static bum.

Like me you aren't the smallest of guys so don't obsess about getting much lower at the front if your body can't take it, there's a real balance between getting aero, getting the power down and comfort. If you lower the saddle a bit you'll probably want to lower the bars by a similar amount anyway. I wouldn't stretch out anymore on the aero bars, any further out and handling becomes slower and you may find you get greater fatigue in your upper body as the weight of your head and shoulders is way behind your elbows rather than being supported by them.

Re: Critique my aero position
« Reply #6 on: July 15, 2008, 10:01:03 pm »
Andy,
I remember reading about the angle of your elbow should be as close to 45 degrees as possible.  This is only good if your knee doesn't hit your elbow though.

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #7 on: July 15, 2008, 10:07:34 pm »
Or my thigh doesn't sink into my gut ;) 

Right, advice on saddle height is consistent with the other place (tritalk) so I'll take it.

** motorboating redacted **

I'll start there, and then trim the rest after that. :thumbsup:
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Re: Critique my aero position
« Reply #8 on: July 15, 2008, 10:09:56 pm »
I've often been told that pedalling through 5-7 O clock should be like scraping S*** off your shoe.

Re: Critique my aero position
« Reply #9 on: July 15, 2008, 10:30:50 pm »
Or my thigh doesn't sink into my gut ;) 

I've never been able to figure how to avoid that. Hence my high sightseeing-tourist position.
scottclark.photoshelter.com

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #10 on: July 15, 2008, 10:59:11 pm »
I think it's this "racing snake" physique.  Or a girdle!
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

gonzo

Re: Critique my aero position
« Reply #11 on: July 15, 2008, 11:16:56 pm »
I'd say that you want to be less stretched out, lower the saddle to stop the rocking (and then the bars by the same amount).

The advice given by Lance's old aerodynamicist is
a) get as low as possible
b) get your arms as close together as possible
c) train in that position a lot so you get used to it


Ignore the 12.5yaw angle; it's an error.

Black solid line = baseline position
Red line = 60mm shorter upper arm (the upper body is rotated at the hip to give a lower front end)
Pink line = forearms touching
Yellow line = forearms between the two positions

David Martin

  • Thats Dr Oi You thankyouverymuch
Re: Critique my aero position
« Reply #12 on: July 15, 2008, 11:38:05 pm »

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"By creating we think. By living we learn" - Patrick Geddes

Re: Critique my aero position
« Reply #13 on: July 16, 2008, 07:49:34 am »
Have a look at <a href="http://www.youtube.com/v/jBseY-5kVw4&rel=1" target="_blank">http://www.youtube.com/v/jBseY-5kVw4&rel=1</a> bloke (that was linked to your video) he has a very smooth pedalling action and an almost static bum.


He is also more forward on the bike and on the saddle nose.
Frenchie - Train à Grande Vitesse

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #14 on: July 16, 2008, 08:24:38 am »
Well, dropping the saddle by 20mm has been a good start.  Much more comfortable in the aero position, not much different in the drops.  Knees are writing me a memo, so I'll let them acclimatise for a day or so before tweaking more.
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Blah

  • Not sure where I'm going
Re: Critique my aero position
« Reply #15 on: July 16, 2008, 10:19:10 am »
I'd say move your saddle forward as much as you can. This will rotate your whole body forward, making it easier to get lower and get a flatter back.

This moving the saddle further forward is the single sensible reason for most people to get a proper TT geometry bike, as it will allow you to be much further forward above the bottom bracket.

This is much better explained on the Cervelo website.

I'm by no means flexible but achieved a fairly good aero position by going for a TT frame and shoving the saddle forward by what looks like a ridiculous amount.

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #16 on: July 16, 2008, 11:12:51 am »
This too has been recommended by the tritalk goons so I'll take it as gospel and have a tinker.  One change at a time (sweet Jesus, tweak it one change at a tiiiiime).

Good to see that my "prayer" style is nicely aero, gonz!   :thumbsup:
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Re: Critique my aero position
« Reply #17 on: July 16, 2008, 11:24:46 am »
It's finding the right compromise between comfort and aero. The shorter the distance, the further you can go towards the latter.

I have a feeling UCI regs on saddle position don't apply to triathlons.

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #18 on: July 16, 2008, 01:11:34 pm »
I don't recall a saddle position in the bike spec (mind you, I was looking for "fixies are okay" and "sure, pennyfarthing, why not?" at the time)
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Blah

  • Not sure where I'm going
Re: Critique my aero position
« Reply #19 on: July 16, 2008, 01:37:26 pm »
I have a feeling UCI regs on saddle position don't apply to triathlons.

I think they apply to some triathlons.

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #20 on: July 16, 2008, 01:45:45 pm »
Even at the back of the pack where I am?  There are people back here riding shoppers.  With baskets.  Who swim keeping their hair dry.

The UCI have better things to worry about... like whether to swirl left or right as they go down the pan (!)
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

gonzo

Re: Critique my aero position
« Reply #21 on: July 16, 2008, 01:46:58 pm »
There's an awful lot of talk on slowtwitch forums where people are requesting non-UCI bikes for triathlons.

Take from that what you will.

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Critique my aero position
« Reply #22 on: July 16, 2008, 01:51:17 pm »
Even at the back of the pack where I am?  There are people back here riding shoppers.  With baskets.  Who swim keeping their hair dry.

The UCI have better things to worry about... like whether to swirl left or right as they go down the pan (!)

I don't believe the UCI have rules against either of those things.

But they do have a rule about saddle position WRT to bottom-bracket - sorry.
Has never ridden RAAM
---------
No.11  Because of the great host of those who dislike the least appearance of "swank " when they travel the roads and lanes. - From Kuklos' 39 Articles

andygates

  • Peroxide Viking
Re: Critique my aero position
« Reply #23 on: July 16, 2008, 02:01:09 pm »
I don't believe the UCI have rules against either of those things.

Oh, come now, they must!  Basket volume and permitted materials (without allowing the use of a fairing disguised as a basket, with carbon-fibre 'baguettes' to act as airflow directors?)! 

This is the UCI we're talking about, after all...
It takes blood and guts to be this cool but I'm still just a cliché.
OpenStreetMap UK & IRL Streetmap & Topo: ravenfamily.org/andyg/maps updates weekly.

Re: Critique my aero position
« Reply #24 on: July 16, 2008, 02:13:28 pm »
There are people back here riding shoppers.  With baskets.  Who swim keeping their hair dry.

Maybe I should give this triathlon thing a try after all.
scottclark.photoshelter.com