Author Topic: Critique my aero position  (Read 8460 times)

Re: Critique my aero position
« Reply #50 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.

Re: Critique my aero position
« Reply #51 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.






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






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.







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.



Re: Critique my aero position
« Reply #52 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!

Re: Critique my aero position
« Reply #53 on: May 14, 2010, 03:44:24 pm »

Re: Critique my aero position
« Reply #54 on: May 14, 2010, 04:02:07 pm »
This should get you nice and aero Andy  ;D

Working my way up to inferior.

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Critique my aero position
« Reply #55 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.
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

clifftaylor

  • Max - "make mine a Beophar Hairball Paste please"
Re: Critique my aero position
« Reply #56 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

David Martin

  • Thats Dr Oi You thankyouverymuch
Re: Critique my aero position
« Reply #57 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.
"By creating we think. By living we learn" - Patrick Geddes

clifftaylor

  • Max - "make mine a Beophar Hairball Paste please"
Re: Critique my aero position
« Reply #58 on: May 14, 2010, 05:13:15 pm »
I doubt that anyone here will be affected by UCI regs, unless Wiggo is lurking.....

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Critique my aero position
« Reply #59 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?!?)
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

clifftaylor

  • Max - "make mine a Beophar Hairball Paste please"
Re: Critique my aero position
« Reply #60 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......

Re: Critique my aero position
« Reply #61 on: May 14, 2010, 05:30:43 pm »
You can use their web site
   Cycling Time Trials > Home
but I find the book useful for planning ahead.

So how's this?


kimroyphotography.com

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?

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Critique my aero position
« Reply #62 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.
Quote
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 ...
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

Fixedwheelnut

  • "If it ain't fixed it's broken"
    • My photos
Re: Critique my aero position
« Reply #63 on: May 14, 2010, 07:56:41 pm »
OK from the Mersey Roads 24 hour 2007, photo bi Brian at Kimroyphotography



 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



 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.
"Don't stop pedalling"

mattc

  • n.b. have grown beard since photo taken
    • Didcot Audaxes
Re: Critique my aero position
« Reply #64 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.)
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

Re: Critique my aero position
« Reply #65 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. ::-)