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Yet another Bike fit critique
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Rider:
Male, 49yo, 5' 10", 152 lbs, 32" inseam (810mm)

Bike (converted road) :
1995 cannondale SR900, 56cm
PD ozero basebar
PD t2+ extensions
Ism PR2.0 seat
Redshift seat post
130mm -20' stem
175mm cranks

Seat Height: 750mm
Nose to extensions: 840mm
Nose to pad edge: 520mm
Pad drop: 90mm
Nose to bb: 5cm aft

Extensions are tight to the stem and 95mm center to center. Angled up at 10 degrees.

All saddle dimensions are to the ism nose (not a standard saddle).

Video is me riding at 0.8 IF:

https://vimeo.com/233597156
Last edited by: Tom_hampton: Sep 14, 17 9:22
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Re: Yet another fit critique [Tom_hampton] [ In reply to ]
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I will comment more, but you dont say what type of goal you have.
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Re: Yet another fit critique [Rider17] [ In reply to ]
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Local Olympic distance tris.
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Re: Yet another fit critique [Tom_hampton] [ In reply to ]
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Hard to critique. Mechanically you look solid. My thought is that your hip angle is so open that you can afford to slam that stem a bit or lengthen the reach to achieve a lower front profile esp if its oly racing
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Re: Yet another fit critique [Rider17] [ In reply to ]
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Stem is slammed.

Longest lowest stem I could find. I once saw a 140mm -35' stem on ebay, but I missed the auction. It's a headshok stem (1.56" steerer).

I do have 5cm of available forward travel on the extensions. I also have 2cm of forward travel on the seat rails.
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Re: Yet another fit critique [Tom_hampton] [ In reply to ]
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listen to others too, but my advise is to move the cockpit as far forward as you can, dont drop it. Still sit on the end of your saddle, but move it back 2cm. More important than any of that is Get an aero helmet and turtle your head
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Re: Yet another fit critique [Rider17] [ In reply to ]
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Rider17 wrote:
listen to others too, but my advise is to move the cockpit as far forward as you can, dont drop it. Still sit on the end of your saddle, but move it back 2cm. More important than any of that is Get an aero helmet and turtle your head

I agree with all of this, especially the bolded part. I´ve fiddled with aero positions on both road bikes and tt bikes for 25+ years and my experience is that on a road frame it is faster overall to have the saddle further back. Otherwise you get to much weight on the front which means that you more often will have to get out of the tri bars to handle turns, wind gusts and passing people.
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Re: Yet another fit critique [fb] [ In reply to ]
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Interesting thoughts. I hope others will chime in, also.

A little more history on the evolution of this position:

I've been working on moving forward and down all summer. I'm not the most flexible, and have had ITB/PFS issues in the distant past. Once upon a time (in a galaxy...), circa 2001, I had a pro road-fit done in Boulder as part of dealing with my ITB/PFS issues. I've used that setup ever since. So, I've been slow and methodical about inching into this position---maintaining the same seat height, just rotating it around the BB (and then compensating for the ISM geometry differences).

I used the static tri-fit article as my defined target position. I finally reached terminus on that two weeks ago...noting that I can't get the pad-drop recommended simply due to parts availability. I've been riding it that way since. Initially I was sitting farther back, and my hips were still in a road position---I felt stretched in the arm pits. Then, I had an "aha!" moment where I pulled forward on the extensions and rotated the hips down. Suddenly, it felt good. Especially over the top of the stroke---still a bit impinged, but much better. I also didn't feel as much like my elbows were trying to slide out from under me.

To relieve the impinging, I raised the seat 1cm which is my first departure from my pedal-box geometry, of the last 15 years or so. That said, it feels very good...actually more like my road pedaling position than it did before the change.

I was also having issues sliding forward on the ISM---I was having to engage upper body muscles to "hold myself in place". Per a previous response from Trent Nix to another "fit critique" (for the same reported problem), I tilted my extensions up 10 degrees (forearm tops are dead-level though---measured). That felt much better, in that I wasn't sliding forward on the saddle. But, once I did that, my shoulder angle felt "too closed"...so I pushed the extensions forward by 1cm. Again, that made a tremendous difference in being able to relax perched on my hips and elbows, with my legs pedaling naturally (sorta like my legs are hanging from fixed points). My torso feels statically stable, now.

The position seems to test "fast" (for me anyway). My house sits on a quiet, rural 7mi loop. I average 21.7mph on 2.75 watts/kg vs. 19.3mph (for 3 laps of the loop) in a standard road position at the same watt/kg. Per the "watts->speed" graph thread that seems pretty respectable.

The post/video above is the final result. I made no further changes after taking and posting the video and measurements.

Note, I have no issues CURRENTLY with handling in this position. I've been up to 38mph in this setup (not blazing fast, but the fastest I'm likely to see in my local races), and have no nervousness, stability, or handling issues. I can manage standard 90' street corners at TT speeds (22mph) in the aero position provided I can take a decent line (use 1-full car lane on entry and exit). I use the basebar on the street to avoid swinging wide into traffic on entry. I don't know what it would be like 7cm further stretched out, and 5cm more forward.
Last edited by: Tom_hampton: Sep 13, 17 11:16
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Re: Yet another fit critique [Tom_hampton] [ In reply to ]
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Shameless bump.
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Re: Yet another fit critique [Tom_hampton] [ In reply to ]
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You need a professional fitter :)

Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Lions don't lose sleep worrying about the sheep
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Re: Yet another fit critique [h2ofun] [ In reply to ]
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So do you.
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