Yet Another Cycling Forum

General Category => Freewheeling => Racing => Topic started by: andygates on July 15, 2008, 08:58:29 pm

Title: Critique my aero position
Post by: andygates 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!

YouTube - Critique my aero position (http://au.youtube.com/watch?v=vjB43BAwQ8M)
Title: Re: Critique my aero position
Post by: Frenchie 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.
Title: Re: Critique my aero position
Post by: teethgrinder 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.
Title: Re: Critique my aero position
Post by: andygates 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. 
Title: Re: Critique my aero position
Post by: David Martin 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
Title: Re: Critique my aero position
Post by: Bigdaveskinnytyre 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 (http://au.youtube.com/watch?v=jBseY-5kVw4&feature=related) 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.
Title: Re: Critique my aero position
Post by: GruB 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.
Title: Re: Critique my aero position
Post by: andygates 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:
Title: Re: Critique my aero position
Post by: Bigdaveskinnytyre 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.
Title: Re: Critique my aero position
Post by: scott 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.
Title: Re: Critique my aero position
Post by: andygates on July 15, 2008, 10:59:11 pm
I think it's this "racing snake" physique.  Or a girdle!
Title: Re: Critique my aero position
Post by: gonzo 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

(http://photos-c.ak.facebook.com/photos-ak-sf2p/v238/208/68/204504692/n204504692_33303106_2687.jpg)
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
Title: Re: Critique my aero position
Post by: David Martin on July 15, 2008, 11:38:05 pm

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Title: Re: Critique my aero position
Post by: Frenchie on July 16, 2008, 07:49:34 am
Have a look at this (http://au.youtube.com/watch?v=jBseY-5kVw4&feature=related) 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.
Title: Re: Critique my aero position
Post by: andygates 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.
Title: Re: Critique my aero position
Post by: Blah 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 (http://www.cervelo.com/content.aspx?m=Engineering&i=TriBikeFit).

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.
Title: Re: Critique my aero position
Post by: andygates 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:
Title: Re: Critique my aero position
Post by: Ian H 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.
Title: Re: Critique my aero position
Post by: andygates 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)
Title: Re: Critique my aero position
Post by: Blah 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.
Title: Re: Critique my aero position
Post by: andygates 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 (!)
Title: Re: Critique my aero position
Post by: gonzo 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.
Title: Re: Critique my aero position
Post by: mattc 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.
Title: Re: Critique my aero position
Post by: andygates 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...
Title: Re: Critique my aero position
Post by: scott 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.
Title: Re: Critique my aero position
Post by: Blah on July 16, 2008, 02:48:48 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...

Well if there aren't any rules against it, it must be because none of Graeme Obree's bikes ever had baskets on them...
Title: Re: Critique my aero position
Post by: mattc on July 16, 2008, 03:33:32 pm

Well if there aren't any rules against it, it must be because none of Graeme Obree's bikes ever had baskets on them...
:D
Title: Re: Critique my aero position
Post by: andygates on July 16, 2008, 10:07:36 pm
Better: more of a square angle at the shoulders and elbows, posterior chain better engaged:

(http://i62.photobucket.com/albums/h95/andygates/gear/flipped_saddle2.jpg)

But it took blasphemy :)

(http://i62.photobucket.com/albums/h95/andygates/gear/flipped_saddle.jpg)
Title: Re: Critique my aero position
Post by: Frenchie on July 16, 2008, 11:19:41 pm
Looks better Andy! Now lower the front a bit.
Title: Re: Critique my aero position
Post by: David Martin on July 16, 2008, 11:25:35 pm
Flipping the seat pin may not let you lower the front of the seat enough. It could be somewhat uncomfortable (to say the least). I have a Profile Designs Fast Forward seatpin. It puts the saddle a wee bit too far forward so I am after a straight through seat pin.

..d
Title: Re: Critique my aero position
Post by: andygates on July 16, 2008, 11:27:01 pm
Seatpin - yes, it's a little beaky, but that's how I like my Brookses and I have well-trained nads that get out the way.  Sumo trick for the TMI win :)

Lower the bars - So my upper arms are more vertical?   We're approaching belly-thigh interference maxima here, but I'll give it a go tomorrow.  T'is past the Fettling Hour now. :thumbsup:
Title: Re: Critique my aero position
Post by: David Martin on July 16, 2008, 11:31:07 pm
Seatpin - yes, it's a little beaky, but that's how I like my Brookses and I have well-trained nads that get out the way.  Sumo trick for the TMI win :)

It's not the nads. it's the perineum. Obviously your seat pin may have more of an angle than mine.

..d
Title: Re: Critique my aero position
Post by: Fixedwheelnut on July 16, 2008, 11:34:27 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)

   TT on a fixie, madness, sheer madness  ;D ;D

  The Aero/comfy balance is personal, I am currently building my old Graham Weigh frame up as a TT bike so I can get a more specific position.
 At present on my Lambert I can get aero but it is uncomfortable and I can't spin fast on it and the saddle won't go further forward without spoiling the bike in my opinion .
  I also intend having the bars slightly higher for more comfort depending on how the saddle position works out.

 PS get out there and ride a TT on it and see how it feels.  :thumbsup:
Title: Re: Critique my aero position
Post by: Frenchie on July 17, 2008, 09:06:01 am
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)

   TT on a fixie, madness, sheer madness  ;D ;D

... but we like it!  ;D  :thumbsup:
Title: Re: Critique my aero position
Post by: Frenchie on July 17, 2008, 09:07:10 am
Lower the bars - So my upper arms are more vertical?   We're approaching belly-thigh interference maxima here, but I'll give it a go tomorrow.  T'is past the Fettling Hour now. :thumbsup:

Try one spacer at a time and see... I'm still working on this too, but as I get more comfortable on the tri bars, I think I could lower the front.
Title: Re: Critique my aero position
Post by: gonzo on July 17, 2008, 09:10:03 am
I should point out that triathletes like their bars positioned very high as a) they have to ride further generally b) they're more interested in comfort than going fast.

(http://photos-d.ak.facebook.com/photos-ak-snc1/v275/78/70/665013082/n665013082_1147771_8383.jpg)

PS. Cervelo vs Planet X; there's a reason why you never see planet X kit in wind tunnel tests. It has been designed to look fast rather than actually designed to be fast. The improvement from an aero frame won't be huge, but it still counts.
Title: Re: Critique my aero position
Post by: Blah on July 17, 2008, 10:03:11 am
b) they're more interested in comfort than going fast.

You mean that when they get off the bike they can't just vom and generally have a bit of a lie down  ;)
Title: Re: Critique my aero position
Post by: andygates on July 17, 2008, 03:41:42 pm
Well yes we can, but the clock is still running. 

For face-saving, you lurch out of transition, find a bush, and vom in that.   :thumbsup:
Title: Re: Critique my aero position
Post by: vorsprung on July 17, 2008, 05:14:44 pm
andy
Don't use the arm rests.  Remove them and rest your forearms on the bars.  Works for me
Title: Re: Critique my aero position
Post by: andygates on July 17, 2008, 05:17:03 pm
 :o

Death!  Deaaaaaath!
Title: Re: Critique my aero position
Post by: Frenchie on July 17, 2008, 05:33:45 pm
andy
Don't use the arm rests.  Remove them and rest your forearms on the bars.  Works for me

The problem I see with this is that you loose your narrow frontal position as your arms will tend to slide sideways. My armrests help keep me compact at the front I feel...
Title: Re: Critique my aero position
Post by: LEE on July 17, 2008, 06:08:17 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. 

Yep, looks like you are stretching to the pedals to me.

whoops, just read all posts.  Way out of date
Title: Re: Critique my aero position
Post by: Blah on July 17, 2008, 07:10:24 pm
For face-saving, you lurch out of transition, find a bush, and vom in that.   :thumbsup:

Thanks Andy, useful advice for September :-)
Title: Re: Critique my aero position
Post by: andygates on July 17, 2008, 07:16:23 pm
I plan on using it!  :)

Weird thing: I was approached in our server room by J Random Engineer today.  "Do you do triathlons?" said he, "I recognise your, er, piercings."  Turns out he recognised me from New Forest (we're both doing the middle there in September) and had just had a great time doing IM CH!
Title: Re: Critique my aero position
Post by: mattc on March 02, 2010, 11:50:50 am
I am having highly speculative TT thoughts, so I shall piggyback here rather than start a new topic.

Having done the 24hr thing (and got  fair idea what works over that distance) I quite fancy spending a season* on finding my true, proper-TT bike, no excuses 10/25 PB. Biggest issue is financial. I'm hoping that if I buy a fairly-new low-mileage bling bike it will hold its value after the 1000 (or less) miles I will put on it before selling. So that seems like the simple plan...

However, that will be a lot of money to splash on something with an untested setup. So would it be better to buy something less bling to play with setup? I suspect it takes several hours on a bike with a new position to adapt enough to know-what-you-like ! OR should I just play with one of my normal bikes with various cheap bars etc ...

Thoughts?

[*probably next year, as I'm a bit late to sort everything out properly this year, AND do my planned Audaxes]
Title: Re: Critique my aero position
Post by: Greenbank on March 02, 2010, 02:21:27 pm
I am having highly speculative TT thoughts, so I shall piggyback here rather than start a new topic.

Having done the 24hr thing (and got  fair idea what works over that distance) I quite fancy spending a season* on finding my true, proper-TT bike, no excuses 10/25 PB. Biggest issue is financial. I'm hoping that if I buy a fairly-new low-mileage bling bike it will hold its value after the 1000 (or less) miles I will put on it before selling. So that seems like the simple plan...

However, that will be a lot of money to splash on something with an untested setup. So would it be better to buy something less bling to play with setup? I suspect it takes several hours on a bike with a new position to adapt enough to know-what-you-like ! OR should I just play with one of my normal bikes with various cheap bars etc ...

Thoughts?

I had similar thoughts. My final conclusion is that I should have a beer (or two) instead and stick to Audax.
Title: Re: Critique my aero position
Post by: andygates on March 02, 2010, 03:08:16 pm
Several hours = a couple of weeks, of short rides at TT intensity.  That deep aero position also uses muscles most upright riders lack (more hams 'n' glutes, less quad) and takes good core strength to hold comfortably and efficiently.

So while I got used to the *position* pretty fast, there was steady conditioning involved in the powerplant. 

God knows what kind of noodle I'll be this year. :-\
Title: Re: Critique my aero position
Post by: mattc on May 13, 2010, 04:23:56 pm
My turn to stick head over parapet:

Image0007 on Flickr - Photo Sharing! (http://www.flickr.com/photos/50206023@N08/4603639672/)

This was taken on a bike I have borrowed. Tell me:

- why/how bad my position is, and
- why I will never get a good position with that frame*.

I've ridden a few miles like that, and the only discomfort is the expected arm strain. But I had that when I first used tri-bars before the 24, so I know it gets better very quickly. (I've gone at least a year since riding on arm-rests). No idea how much my power generation is affected.

*which is 653 for steel freaks.
Title: Re: Critique my aero position
Post by: Fab Foodie on May 13, 2010, 09:19:30 pm
I think it's this "racing snake" physique.  Or a girdle!

We call it having an 'Aerobelly'...
Title: Re: Critique my aero position
Post by: Manotea on May 13, 2010, 09:21:29 pm
I had similar thoughts. My final conclusion is that I should have a beer (or two) instead and stick to Audax.

Was that before or after you bought the Powertap wheel? Lol!
Title: Re: Critique my aero position
Post by: disrail on May 14, 2010, 10:54:41 am
In reply to Matt. The position looks ok.

Your torso is almost horizontal. neck tucked into the shoulders. I can't see how arched your back is from the picture however as it's cut off.

I think just as important as the relative positions of contact points is the flexibility of the rider and the shape they create with what they've got. The flexibility to rotate the torso forward is important. If you don't have this move the seat forward. Secondly, pull your belly button towards the top tube, helping to flatten the back higher up.

Also tilting the bars up a little may be more aero, just 5-10 degrees above horizontal. The UCI have banned the praying mantis position where the forearms point up, so it must be good!! (Also the head can be brought close to the hands, http://velochimp.com/wp-content/uploads/2006/02/landis_tt_closeup_sm.jpg)

When pedaling, keep your knees in to the top tube*. If they fit close behind your elbows on the top of the stroke then all the better.

I'll get my TT position on here soon, it'd be good to get some comments. I think with photos the front view may be the most important, as its the frontal profile which is what we are assessing.

* a guy in our club used to ride with Graeme Obree. Apparently he played around with putting WD40 on the inside of his knees to reduce the friction as they rubbed the top tube.
Title: Re: Critique my aero position
Post by: disrail on May 14, 2010, 12:53:36 pm
OK, any opinions / advice appreciated. I can get 3 distinct positions from my current setup.


First, Praying Mantis. I have to move back on saddle to drop my head behind my hands.

(http://lh5.ggpht.com/_qLKAJRvJRSA/S-02z40QCBI/AAAAAAAAAJw/cwNKMjvbwlg/s640/P1012789.JPG)

(http://lh6.ggpht.com/_qLKAJRvJRSA/S-03i9z5-UI/AAAAAAAAAKY/-TwuYQ4d3PI/s512/P1012794.JPG)


Secondly, making upper arms vertical, lower arms almost horizontal. I need to be further forward on seat.

(http://lh3.ggpht.com/_qLKAJRvJRSA/S-020tyjYxI/AAAAAAAAAJ0/YM4SiDxaJ_A/s640/P1012791.JPG)

(http://lh4.ggpht.com/_qLKAJRvJRSA/S-03j2rPrrI/AAAAAAAAAKc/QRkoUvuUQiw/s512/P1012795.JPG)


And lastly, bringing the forearms fully flat and back on the bars. I'm back on the saddle again and my knees tuck in nicely behind the elbows.

(http://lh5.ggpht.com/_qLKAJRvJRSA/S-021L-r-JI/AAAAAAAAAJ4/w58XWW0NmP4/s640/P1012793.JPG)

(http://lh5.ggpht.com/_qLKAJRvJRSA/S-03kSnCqKI/AAAAAAAAAKg/pfuOPhq_aZc/s512/P1012802.JPG)



I have no idea which is fastest. I feel safer further back on the saddle and alternate between the 1st and 3rd positions on TTs. Just looking at the frontal shots, they're a bit off, but good enough.


Title: Re: Critique my aero position
Post by: Tewdric on May 14, 2010, 01:18:27 pm
3 looks the best - you need to bring your tribars back to keep your elbow at that angle.  It looks a bit low though - you'll probably be faster with the bars a little higher, as breathing will be more efficient and itll be easier to get the power down. You could try bringing your saddle up and forward too to rotate your position clockwise IYSWIM. Depends on your event to a degree of course - you can be more radical on a 10 than in an ironman!
Title: Re: Critique my aero position
Post by: Ian H on May 14, 2010, 03:44:24 pm
An old fart on a bike: http://farm2.static.flickr.com/1273/4603112909_e7f70c9ac3_o.jpg
Title: Re: Critique my aero position
Post by: Biff on May 14, 2010, 04:02:07 pm
This should get you nice and aero Andy  ;D

(http://i286.photobucket.com/albums/ll85/registered-user/scapinhoggsetup.jpg)
Title: Re: Critique my aero position
Post by: mattc on May 14, 2010, 04:35:08 pm
What noone has mentioned is that my bike is illegal.

the peak of the saddle must be at least 5 cm behind a vertical plane passing through the
bottom bracket spindle


Hrumph. I think I'll have to get used to riding on the nose. Moving my butt back 5cm means moving the arm-rests far further than possible with the kit I have.

The biff bike should be OK.
Title: Re: Critique my aero position
Post by: clifftaylor on May 14, 2010, 04:38:56 pm
What noone has mentioned is that my bike is illegal.

Only if you intend to ride UCI events, rather than domestic TTs
Title: Re: Critique my aero position
Post by: David Martin on May 14, 2010, 05:09:57 pm
What noone has mentioned is that my bike is illegal.

the peak of the saddle must be at least 5 cm behind a vertical plane passing through the
bottom bracket spindle


unless you go and blag an anatomical exemption from teh comissaire before the start in which case you can get it up to the vertical plane.

It is a rule which is unfair on shorter riders.
Title: Re: Critique my aero position
Post by: clifftaylor on May 14, 2010, 05:13:15 pm
I doubt that anyone here will be affected by UCI regs, unless Wiggo is lurking.....
Title: Re: Critique my aero position
Post by: mattc on May 14, 2010, 05:17:24 pm
That certainly is a UCI rule I quoted - what are the rules in UK events (CTT?) ? I assume there are equipment rules?!? <flits over to Dark Side fora ... >

Do I need to buy a CTT handbook? (spend money?!?)
Title: Re: Critique my aero position
Post by: clifftaylor on May 14, 2010, 05:27:43 pm
"Cycling Time Trials" is the governing body (RTTC as was). They have some regs about wheels (discs, deep rims etc), but not a lot about bike dimensions.
Their website is having probs at the moment......
Title: Re: Critique my aero position
Post by: токамак on May 14, 2010, 05:30:43 pm
You can use their web site
   Cycling Time Trials > Home
 (http://www.ctt.org.uk/) but I find the book useful for planning ahead.

So how's this?
(http://www.kimroyphotography.com/gallery/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=51280&g2_serialNumber=1)

kimroyphotography.com (http://www.kimroyphotography.com/gallery/gallery2/main.php?g2_itemId=51280)

It's a small road frame so I've compensated with a short stem. I'm thinking of trying a stem with a steeper angle though, just to get a bit lower down?
Title: Re: Critique my aero position
Post by: mattc on May 14, 2010, 05:33:37 pm
Thanks for this. Clearly there are compromises between
Comfort,
Aero, and
Power
In reply to Matt. The position looks ok.

Your torso is almost horizontal. neck tucked into the shoulders. I can't see how arched your back is from the picture however as it's cut off.

I think just as important as the relative positions of contact points is the flexibility of the rider and the shape they create with what they've got. The flexibility to rotate the torso forward is important. If you don't have this move the seat forward. Secondly, pull your belly button towards the top tube, helping to flatten the back higher up.
Now this is an interesting point. I'm conscious of this open-hip-angle business i.e. too small a hip angle will limit your power. I stumbled on a tri setup vid earlier which recommended bending at the navel; this sort of seemed sensible, but gets away from "flat backs", and contra to your  pull your belly button towards the top tube
I'm certainly more comfortable with a bit of an arched torso, legs feel less constricted. Flat backs reduce frontal area, but I need power ...

I've also read about a box-shape i.e. hip angle and shoulder (torso-upperarms) angles of 90'. This was also aimed at Tri riders, who need more comfort for their longer efforts.
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Also tilting the bars up a little may be more aero, just 5-10 degrees above horizontal. The UCI have banned the praying mantis position where the forearms point up, so it must be good!!  
Now you mention it, I did the 24h with much higher hands, so I'll try that again - nice one.

My main thought on the bike is that I may need my elbows nearer to me (the 90' shoulder angle thing). Purely for comfort, not aero. My stem is miniscule already! Not sure how far back other bars could put the arm-rests.

Food for thought ...
Title: Re: Critique my aero position
Post by: Fixedwheelnut on May 14, 2010, 07:56:41 pm
OK from the Mersey Roads 24 hour 2007, photo bi Brian at Kimroyphotography

(http://farm3.static.flickr.com/2270/1842316365_4a9eb391e1.jpg) (http://www.flickr.com/photos/fixedwheelnut/1842316365/)

 This was fine until the 12 hour point when the saddle position and cramp in my glutes was agony and I had to sit on the tops more to change position.

and this is my Graham Weigh on the Bexley CC 10 at West Kingsdown, Photo by Roger Munn

(http://farm4.static.flickr.com/3005/2782774662_e57dd67bc6.jpg) (http://www.flickr.com/photos/kent-guy/2782774662/)

 I can probably afford to go a bit lower on shorter distances but find bike control means I can spend more time on the aero bars when they are slightly higher so end up being more aero for a higher proportion of the time, i.e. nopt having to move to the handlebars/tops.
Title: Re: Critique my aero position
Post by: mattc on May 16, 2010, 05:08:42 pm
So how's this?
http://www.kimroyphotography.com/gallery/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=51280&g2_serialNumber=1
I know everyone with modern bars seems to do it, but do you not find that wrist position really uncomfortable?

(I can't see an aero benefit as the airflow goes on to hit your groin/thighs anyway.)
Title: Re: Critique my aero position
Post by: токамак on May 17, 2010, 08:14:04 am
So how's this?
I know everyone with modern bars seems to do it, but do you not find that wrist position really uncomfortable?

(I can't see an aero benefit as the airflow goes on to hit your groin/thighs anyway.)

On the first couple of 25's I did this year, my wrists did start to ache a bit towards the end. However, I think I must have adapted my grip slightly now, as even on a 50, I don't get any discomfort. To be honest I opted for straight bars because I prefer the aesthetic. ::-)