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 Post subject: TT position Critique
PostPosted: Thu Jun 13, 2013 9:27 pm 
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I've decided to get serious about TT position this year since it hasn't changed from when i first set it up years ago so i'd love to hear some people's critique of my new position. I choose these two because they seemed the best balance of power output and comfort. I tried a stem slammed down position but found it was too cramped, whilst i could hold it i also couldn't lift my head up enough to see.

The photo on the left is as low as i could get my head and still be able to see up the road (somewhat), however it rounds the back out a fair bit. The Photo on the right is a bit higher but provides a flatter back which i've always assumed was the best approach.

Anyway feel free to add anything (try and be constructive though) i could try or am missing. Many Thanks.

I've decided to get serious about TT position this year since it hasn't changed from when i first set it up years ago so i'd love to hear some people's critique of my new position. I choose these two because they seemed the best balance of power output and comfort. I tried a stem slammed down position but found it was too cramped, whilst i could hold it i also couldn't lift my head up enough to see.

The photo on the left is as low as i could get my head and still be able to see up the road (somewhat), however it rounds the back out a fair bit. The Photo on the right is a bit higher but provides a flatter back which i've always assumed was the best approach.

Anyway feel free to add anything (try and be constructive though) i could try or am missing. Many Thanks.

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http://i1293.photobucket.com/albums/b58 ... bb128c.jpg" onclick="window.open(this.href);return false;


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 Post subject: Re: TT position Critique
PostPosted: Thu Jun 13, 2013 11:28 pm 
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According to Damon Rinard, lower is nearly always lower drag. So if you can deal with the lower position...

Do you have a PM? If so, have you done any field testing?

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 Post subject: Re: TT position Critique
Posted: Thu Jun 13, 2013 11:28 pm 


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 Post subject: Re: TT position Critique
PostPosted: Thu Jun 13, 2013 11:53 pm 
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Saddle looks a bit high perhaps?


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 Post subject: Re: TT position Critique
PostPosted: Fri Jun 14, 2013 1:43 am 
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Field test if possible? You will be surprised how much of a difference having your head and torso a couple of inches higher than in the left photo can make to your CdA... If you can produce the same power in the lower position I'd personally go with that.

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 Post subject: Re: TT position Critique
PostPosted: Fri Jun 14, 2013 11:59 am 
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Location: Norway, Oslo
First of all: Is this a still picture or a picture snapped from a video (looks static due to no movement in wheel)? Static position can be quite a lot different to a dynamic position. I would love to see a video, but based on the pictures I have the following comments:

I like the curve on your back better on the left picture. Your head and helmet dissapears more in front of your back, which contributes to a smoother airflow. I also like the angles of your arms better in the left picture. Closer to 90 degrees both between upper body - upper arm and upper arm - lower arm. It puts less stress on your muscles to stay tucked in.

You do have quite a bit of "toe down" in both positions. I agree with DJT21, your saddle looks a bit to high. I would lover it so you get a <148 angle where you are now 150/151. This will most likely help you produce more power, as muscles don't produce optimal power when they are extended this much. When the saddle is this high I also suspect your hips to be wiggling from left to right in order to help you reach down to the bottom of the stroke. If you lower your saddle a little bit your hipbones will stay much more stable, making you produce more power, be more aero and help keep your back straight. I wouldn't bee surprised if a "birds eye view" of you would look a little bit like a snake-ish movement instead of a straight and completely still back.

What's your minimum knee angle? When your pedal is the closest to your body, what is the angle between lower and upper leg? What are your goals? <40km tt or >140km ironmans?

My reccomendations:

Lower saddle
Lower the bars
Measure minimum knee angle
Keep the back more rounded as in left picture
Post an updated picture :thumbup:
Post a frontal view
Use dartfish software to analyze video

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 Post subject: Re: TT position Critique
PostPosted: Fri Jun 14, 2013 9:51 pm 
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Posts: 127
Foreword:- all advice below based on premise of position for shortish TT <60km

1. Test test test and test again! (in the uk time triallists are often known as testers, originally this referred to testing your self against the clock, but i think these days it is equally applicable to position and gear testing/tweaking)

2. Saddle "looks" higher than a classical fit would give, maybe by 5-10mm. I would be less clinical than most about changing this, mine is about the same and i generate more power like that (probs due to long term adaptation) it may be the case you are the same. and changing habits like that can take a fair while (i know i should change mine but cant quite bring my self to sacrifice a season to get to the same adaptation level!)

3. hand to pad position in the first image is better, hand and forearm should ideally be in a line, you are exposing more forearm to the wind in the later image.

4. If money allows, maybe a different helmet, looks like it fits your position quite well, but not quite as optimally as it could do (selector might be better). PS the concave inside of the advantage (and other helmets) in the tail, tested slower than a filled in one for me.

5.try to flatten the back out a bit, most people I've helped do field testing on have seen improvements on a flat back. It is a bit of a complicated story, but rounded back is helping the helmet air flow, and the shape is generally smoothing the air. but in my experience the increase in frontal area is a cause of net increase in drag over the flat version.
to that end, you've got to lengthen the distance between the contact points either cockpit if regulations allow it to go further forward, or maybe seat a little more rearward, if power generation can take the change? (back to more testing!) and to focus on keeping your pelvis rotated forwards further. Practice makes perfect! I can see how all this is a big commitment though.

6. I'd say pic 1 is better overall, the image shows a few signs of corroborating your experience with a slammed stem, as it looks you are on the very on the edge of what you could sustain without losing power.
pic 2 has a marginally flatter back as you say, but significantly more torso in the wind.

7. tilt your helmet back on your head a little more, looks like its impinging your vision, and get used to looking through your eyebrows, but keep your head still.

8. do the shrug! that is to say, shurg your shoulders forwards and turtle your neck a little more like this guy @0.25 https://www.youtube.com/watch?v=gQfnpp4UOX0 Very difficult to adapt to do for more than a few mins at a time but can make 10w or more difference to your drag, so worth experimenting with.

and as stated above, video of the positions at race pace intervals is much more telling than static shots, I can get into a smaller position than zabriskie static, but I cant do that in a race! + frontal image for critique.


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 Post subject: Re: TT position Critique
PostPosted: Sat Jun 15, 2013 12:31 am 
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Of all the things happening in those pic's, I don't think a new helmet should be a high priority - if he can hold position 1 in a race.

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 Post subject: Re: TT position Critique
PostPosted: Sat Jun 15, 2013 10:14 am 
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@ tinea I see what you mean, its not a big issue, but its all minimal gains isn't it.

And i should clarify that the bullet points were numbered, but should not be read in order of importance, just how the information dragged itself from my head.


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 Post subject: Re: TT position Critique
PostPosted: Sat Jun 15, 2013 10:59 am 
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That helmet doesn't look like it has a lot of vents - could little difference between that and a Selector really.

They look like Campag cranks, guessing not a Campag SRM? Coin would be better spent on a PM.

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 Post subject: Re: TT position Critique
PostPosted: Sat Jun 15, 2013 9:05 pm 
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Thanks everyone for the feedback.

The picture on the left is closer to how i used to have my setup. I basically came to this position kind of out of the box, as in i just set the bar as low as possible and went with it. I placed 2nd on my first TT so i didn't want to mess with a good thing and i've had pretty good results since (won a few, 2nd at provincials). In that position i can see about 20 ft up the road with the occasional glance up to see further, but my worry was always i was closing my hip angle too much and perhaps a higher position might give me better power output. The photo on the right is the set up i used on my last 15k TT which i did in 20 minutes so that tells me it works. I'll be doing another TT this Thursday (barring rain again) so i'll try the lower position and see how that goes.

As for saddle height.......I was reading up on the Holmes method that was in Bikeradar a while back and thought i'd give it a go. I have to say this is the best power output i've gotten so far and is much more comfortable, especially when used with Rotor rings, it just seems so smooth.....no rocking of the hips at all. Took a while to get used to it but i'm a big believer in this method now.

I do have a PM so i'll try and do some field tests. In the meantime i'll do a dartfish analysis to get a more dynamic picture of whats going on.

btw......my goal is to win provincials in my age category this year. I lost by 5 sec last time around and can't help but wonder if setup may have made a difference


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 Post subject: Re: TT position Critique
PostPosted: Mon Jun 17, 2013 5:11 pm 
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Here is an updated position shot using Dartfish and in the lowest position i can go. The top set is with my head in what i'd consider to be a more realistic position in terms of comfort and visibility. The bottom is with my head and shoulders shrugged in as much as possible. I'll be doing a 15k TT this week to see how the new position feels. Funnily enough this is pretty much how i had my position originally. Again i can't help but wonder if my hips are too closed off (I've been spending far too much time looking at Wiggo's position in comparison).

Again any feedback is greatly appreciated

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 Post subject: Re: TT position Critique
PostPosted: Wed Jun 19, 2013 10:31 pm 
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I think it looks good. No need to get lower. Can you post a frontal picture as well?

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 Post subject: Re: TT position Critique
PostPosted: Sat Jun 22, 2013 1:34 am 
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Location: Bay Area
Saddle still looks high to me. Id lower it 1cm and reassess. Without power and/or drag data this and seeing you pedal this thread is somewhat useless.

A client of mine looked the same in still photos, but had a lot of problems when on the bike. We lowered his seat 15mm, moved it back 10mm, raised his pads 15mm and put them out 15mm per side. Hips stabilized, power increase, back flattened, drag decreased, and he took 1:30 off of a 20k TT from his time last year despite having the same power output. There is a threshold of how low you can go before your upper body starts drawing lactate and destabilizes. San Milan has a few articles or references to this online and a TT nerd friend of mine has done some wind tunnel testing w/ blood lactate data and found that the increase in drag by running his pads 1 inch higher and 1.5 inches more inwards was completely worth when they tested his power output and blood lactate both in and out of the wind tunnel. That change alone helped him break a sub 50 40k, so I'd hesitate to really go further into depth with this until you can provide more detail.

People with seat heights that are too high often feel "powerful" grinding out a big gear on a TT bike I've noticed.

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 Post subject: Re: TT position Critique
PostPosted: Mon Jun 24, 2013 11:55 pm 
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[quote="KWalker"]Saddle still looks high to me. Id lower it 1cm and reassess. Without power and/or drag data this and seeing you pedal this thread is somewhat useless.

I took your advice and dropped the saddle by 1cm.....and attached is a video pedaling which i hope helps. I haven't noticed a huge change from being low vs being higher. My 15k TT times have remained roughly the same so perhaps it's all a moot issue.

But again any advice or recommendations is always appreciated.

http://s1293.photobucket.com/user/Phili ... c.mp4.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;


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 Post subject: Re: TT position Critique
Posted: Mon Jun 24, 2013 11:55 pm 


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