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Bike fit exercise results (if you gave me your height and saddle height)
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for those of you who gave me your height and saddle height...

i thought i'd start a new thread on this, hope you don't mind, to keep this a little better organized. here are some results, if i didn't give you results in the prior thread:



there are many caveats here!

1. the point if this exercise is to tune an online tool for a direct selling bike maker that wants to be able to better tell the customer which bike to buy (frame size, stem size, pad pedestals, etc.). the frame maker already has a pad x/y prescriber (you type in your pad x/y, here's the prescription). the tool i'm working on now is to generate pad x/y via simple exercise. you could port the pad x/y into the prescriber for the solution.

2. this is not bike fit tool! this is the fallback. if you have nothing - no good sense of your own position; you haven't gone to a proper fitter for a bike fit; you're too embarrassed to put a video of yourself on slowtwitch to help get your fit dialed - but you want to buy this company's bike, this is a tool to help you choose the bike to buy.

3. this tool heavily relies on conformity to the norm. as you see, those blue dots are you, and you don't conform. the red dots are male pros. they conform somewhat better than the rest of you. this tool is built with the assumption that the bike you'll choose conforms to the norm.

4. blah blah blah. too many caveats to list. but they would or should be listed with the tool, so, if you (for example) want the "gentleman's fit" you could (say) add 20mm to "y" and subtract 10mm from "x". or, if you think you'll eventually get yourself into a better position, and ride more aggressively, the tool would coach you how to buy the solution that had 20mm of drop available by taking out pad pedestals, and 15mm of forward pad placement.

5. you'll see that this tool has no guidance for saddle placement. the suggestion here is that you place the pads first - the bike perhaps comes pre-positioned from the factory - and you place the saddle where you need to so that you're not too stretched, etc.

6. this should conform - if the math is right - to static formulas i've developed for armrest elevation drop, cockpit distance, seat angle and so forth. the assumption here is that you're riding with 79.5° of seat angle as measured in the old days before split-nose saddles. yes, that means this tool is assuming you'll ride with your hips in the position that represents long held assumptions as to the mean seat fore/aft.

all that said! this is an exercise. i'm interested now in hearing where you are, rather than where this tool says you "should" be. what i'd like from you all are:

1. what is your pad x/y?
2. are you long in the torso or long of leg?
3. anything else you want to say.

after i get a couple things off my desk i'll place a schematic on this thread telling those of you who haven't yet participated how to measure.


Dan Empfield
aka Slowman
Last edited by: Slowman: Aug 7, 17 8:42
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Reposting from the crickets thread.

Slowman wrote:
found it. you slipped by me. what i get is:

pad y = 582
pad x = 456

do you know how that compares with how you're currently riding?

Pad Y = 537 (this is pad included)
Pad X = 505

I've been told I am a long torso type, but really feel like I am more on the even proportioned side. I like to be low and stretched out and ride further back on the my saddle than the measuring point, which because of how the nose rolls off on my Dash it would lead me to think it might be skewing my number?

I don't think the numbers generated are that far off, but I also struggle finding integrated front end bikes that fit me without running under-mount extension setups. So, buying a bike with 580ish stack range would probably make it hard for me to hit my 535ish number.
Last edited by: LAI: Aug 7, 17 12:32
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Re: Bike fit exercise results (if you gave me your height and saddle height) [LAI] [ In reply to ]
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love to see pics of you on the bike or of the bike itself at least.

note where you are on the chart above. no pro athletes anywhere in your solar system. just the other kooky folk.

bear in mind, if this tool i'm working on spat out 537/505 i would immediately change it. i'm confident there's no mix of morphology + riding ambitions that would generate 537/505.

that said, i'd be happy to eat my words where i harsh your position. but a pic is going to tell the story.


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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So your prescription is 666/495. You're not far off, actually. My fit is 671/498, and I'm comparatively long of leg for my height. I think at this point, a "general fit" for me is closer to 670/500, which would put you about 5mm shy on both axes.

I'm curious to set my bike up as you're proscribing and see if I can tell a difference. I'm guessing that if you set my bike to your coordinates and did a blind test with me I wouldn't be able to spot by feel alone which was which.
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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5'10'
saddle height 738mm

David
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Slowman wrote:
love to see pics of you on the bike or of the bike itself at least.

note where you are on the chart above. no pro athletes anywhere in your solar system. just the other kooky folk.

bear in mind, if this tool i'm working on spat out 537/505 i would immediately change it. i'm confident there's no mix of morphology + riding ambitions that would generate 537/505.

that said, i'd be happy to eat my words where i harsh your position. but a pic is going to tell the story.


Here is a shot from this past week. Not the greatest, but it is all I have: I'll take a proper side photo when I get home and grab the numbers you are asking for.[/img]


Also, here is the position I ran last year and the numbers on this position are "kookier" If I remember correctly it's something like: y = 565; x = 550




Edit: Finally got around to grabbing a hosting service that works.
Last edited by: LAI: Aug 9, 17 2:00
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Would still like to see what you say...🙂

Height 183cm
Saddle 78cm
Currently 625/470 or so pad stack/reach
Last edited by: zooropa: Aug 7, 17 14:26
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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height: 6'3" or 190.5cm
saddle: 80.5cm

will add current stack/reach this evening
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Height: 6'2" (187.9cm)
Saddle Height: 81.9cm

CJ
Slow, Old Guy
Last edited by: HeyCJ: Aug 7, 17 14:34
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Slowman wrote:
love to see pics of you on the bike or of the bike itself at least.

note where you are on the chart above. no pro athletes anywhere in your solar system. just the other kooky folk.

bear in mind, if this tool i'm working on spat out 537/505 i would immediately change it. i'm confident there's no mix of morphology + riding ambitions that would generate 537/505.

that said, i'd be happy to eat my words where i harsh your position. but a pic is going to tell the story.

Okay got a better photo and confirmed my Y at 508mm. Pad drop is 160mm, so nothing crazy there (measured to the center of the saddle). Also, do you want pad thickness included in the X? I always include it, but it does compress some. Probably can pull 5mm out of the X due to pad compression and add it to the drop if you're pulling it.

Now, this position is really comfortable for me and it is one I have evolved into over a few years after initially being fitted in 2009. So, what about those numbers seems so crazy? Is it the combination? Or perhaps just the Y? Can't be the X, as that's not low at all for me. Remember I am a little guy.

Lastly, I ride the pointy bit of my elbow right around the middle of the pad and hold the shifters with barely any of the extension in my grip.

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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Current fit
Pad X: 485
Pad Y: 610

Only picture I've seen of myself racing on the new bike this season.


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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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1. what is your pad x/y?: 515/645
2. are you long in the torso or long of leg?: *very* long in the torso
3. anything else you want to say: Current fit is very similar to what I had been using for several years, only change was a few months ago during a Roadshow fit you suggested raising my pads a few cm, previous x/y was 515/625.

"I'm thinking of a number between 1 and 10, and I don't know why!"
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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x = 520
y = 650

Not very low. Old guy just starting.
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Just got back from a weekend away so can check what I measured on Friday.

You had me at 590/474, I measured 554/450.

For the stack my number is skewed a bit since I run my seat a couple cm lower than a proper fit dictates, but otherwise I quickly develop pain on the outside of my knees.

Surprised you had my reach that much larger. When I do a uci regulations TT I actually have to swap out my 90 mm stem for a 70 mm stem to comply. I switched to a Sitero saddle this year which doesn't need adjusting to meet the uci 5xm behind the bb reg.
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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One more for you:

To top of ISM saddle 81.5cm (from BB)
My height 185.5cm

BB is 27cm off the ground, measurement from BB to centre of saddle bracket (on Cervelo s5) is 75cm
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Slowman] [ In reply to ]
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Pictures of my position plus posts/reply from original thread. Took pics with helmet on per Jens suggestion, one with leg at the bottom of the stroke and one at the top (roughly):





As I describe below I've moved pad x forward since my last fit while keeping saddle position and pad y constant (one 10 mm spacer under the pads, I have all the pieces to go higher or lower in 5 mm increments). I have plenty of room to move pad x forward or backward. Any thoughts/comments/critiques please let me know.

Northy wrote:
Slowman wrote:
Northy wrote:
Height: 6' 2"
Saddle height: 822 mm
Pad x: 527 mm
Pad y: 678 mm

what i have for you is

pad x = 500
pad y = 667

now, as to the difference in pad x (because pad y is pretty close). to me, 822mm of saddle height is tall for a guy 6'2". so, my predictor is adjusting your pads back a bit because it thinks you don't have a very long torso. i'd love to see a pic of your position, because you either:

1. ride VERY steep;
2. have a pretty big shoulder angle when you're in aero;
3. you measured pad x long;
4. i'm full of shit (always a possibility).


I'm no morphological freak but I do have long legs and short torso. Plus my effective seat tube angle is 80°.

Pretty interesting the the pad y is so close, and the pad x you predict is actually closer to the recommendation that Jonathan Blyer arrived at when he fit me: 484 mm to the center of the pad. I've been toying around with pad x over the past ~3 months while trying different extensions (original PD T5s were too short and I didn't like their low angle, currently on Vuka EVO 110s which are plenty long and a lot higher). With the greater length of the Vuka extensions I, perhaps unwisely, have moved the pads forward. Only the pad x though, I haven't changed pad y or seat position.
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Re: Bike fit exercise results (if you gave me your height and saddle height) [duckies] [ In reply to ]
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duckies wrote:
I'm curious to set my bike up as you're proscribing and see if I can tell a difference.

in this exercise - using an analogy - you gave me your ear length and height and i remotely prescribed your shoe size. therefore, my recommendation, don't do that! this exercise is me performing surgery with a butter knife. what you've come up with on your own using much better input and data than i've asked you to give me is certainly better than relying on my math.


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [david] [ In reply to ]
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david wrote:
5'10'
saddle height 738mm

y = 620
x = 482


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [zooropa] [ In reply to ]
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zooropa wrote:
Would still like to see what you say...🙂

Height 183cm
Saddle 78cm
Currently 625/470 or so pad stack/reach

y = 643
x = 491


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [ctflower] [ In reply to ]
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ctflower wrote:
height: 6'3" or 190.5cm
saddle: 80.5cm

will add current stack/reach this evening

y = 668
x = 513


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [HeyCJ] [ In reply to ]
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HeyCJ wrote:

Height: 6'2" (187.9cm)
Saddle Height: 81.9cm

y = 665
x = 501


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [LAI] [ In reply to ]
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in my opinion, 160mm of pad drop is not crazy. for jordan rapp who's 6'3". your pad drop is fine, but it's very low, outlier low, for your morphology. otherwise...

i don't think you should change your position. but there is no way any prescriber could come up with your position based on your morphology. so for the purposes of this exercise i'm satisfied. thank you for helping out with this.

oh, and nice bike! ;-)


LAI wrote:
Slowman wrote:
love to see pics of you on the bike or of the bike itself at least.

note where you are on the chart above. no pro athletes anywhere in your solar system. just the other kooky folk.

bear in mind, if this tool i'm working on spat out 537/505 i would immediately change it. i'm confident there's no mix of morphology + riding ambitions that would generate 537/505.

that said, i'd be happy to eat my words where i harsh your position. but a pic is going to tell the story.


Okay got a better photo and confirmed my Y at 508mm. Pad drop is 160mm, so nothing crazy there (measured to the center of the saddle). Also, do you want pad thickness included in the X? I always include it, but it does compress some. Probably can pull 5mm out of the X due to pad compression and add it to the drop if you're pulling it.

Now, this position is really comfortable for me and it is one I have evolved into over a few years after initially being fitted in 2009. So, what about those numbers seems so crazy? Is it the combination? Or perhaps just the Y? Can't be the X, as that's not low at all for me. Remember I am a little guy.

Lastly, I ride the pointy bit of my elbow right around the middle of the pad and hold the shifters with barely any of the extension in my grip.


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [geauxTT] [ In reply to ]
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geauxTT wrote:
Current fit
Pad X: 485
Pad Y: 610

i like your position, and i have you at 607/477 so i don't think my position prescriber would have recommended the wrong bike size in your case. thank you for your help.


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [Warbird] [ In reply to ]
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Warbird wrote:
1. what is your pad x/y?: 515/645

in your case my prescriber would've miserably failed you. thank you for helping with this exercise.


Dan Empfield
aka Slowman
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Re: Bike fit exercise results (if you gave me your height and saddle height) [RonanIRL] [ In reply to ]
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RonanIRL wrote:
One more for you:

To top of ISM saddle 81.5cm (from BB)
My height 185.5cm

BB is 27cm off the ground, measurement from BB to centre of saddle bracket (on Cervelo s5) is 75cm

659/493


Dan Empfield
aka Slowman
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