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 Post subject: An analysis of setback
PostPosted: Wed Dec 19, 2012 12:47 am 
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I was fiddling around with my setback this week and decided to do a quick bit of research. I was able to find setback measurements for 33 current pros and made a quick spreadsheet. The results are pretty... average. The riders on the shorter or more forward end of the spectrum are simply tiny and/or sprinters (Cavendish is one of the first five). The variance between rider height and setback is markedly diminished with height above 1.83m. The bolded numbers at the bottom of the spreadsheet are the averages.

Even though this is a small and select sampling, I think it's interesting to see it presented in this way as opposed to armchair analysis of James Huang's photos. My hope is also to put this out there to counter the BS that is spewed on beginner boards about pros running "massive" amounts of unholy setback, and newbs thus thrusting their saddles forward.


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setback graph.JPG [ 27.83 KiB | Viewed 2604 times ]


Last edited by AGW on Wed Dec 19, 2012 1:22 am, edited 1 time in total.
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 Post subject: An analysis of setback
Posted: Wed Dec 19, 2012 12:47 am 


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PostPosted: Wed Dec 19, 2012 1:05 am 
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Not that it would be easy to accurately obtain, but inclusion of upper and lower leg length into the analysis could prove enlightening, as, for a given overall height, they can significantly bear on setback.


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PostPosted: Wed Dec 19, 2012 1:36 am 
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also saddle design. the nose of a arione cx for example is 30mm longer than that let say of a specialized toupe.

[by definition on the interwebz setback is like from nose [down] horizontal difference to c-c bb]


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PostPosted: Wed Dec 19, 2012 1:40 am 
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Those are both good points. I imagine that rail design can also skew this a mm or 2 as some saddles differ in terms of where the mounting area is located beneath the saddle.


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PostPosted: Wed Dec 19, 2012 2:55 am 
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I would rather see a saddle height vs setback plot, to reduce the skew from different rider proportions.


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PostPosted: Wed Dec 19, 2012 2:57 am 
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Don't know why I didn't think to include that, but I'll add that tomorrow.


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PostPosted: Wed Dec 19, 2012 3:04 am 
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If you just look at saddle height, you won't see the impact of upper vs. lower leg length on setback. All else equal, shorter lower leg (for a given saddle height) will tend to have more setback.


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PostPosted: Wed Dec 19, 2012 3:08 am 
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True, but we're not likely to ever see rider measurements like that (or at least ones that are taken in some consistent manner). One could try to find general population data on upper vs lower leg lengths though. Some argue that pros are morphological freaks with proportions that the general population is unlikely to have, but I seriously doubt that.


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PostPosted: Wed Dec 19, 2012 3:15 am 
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I have been tabulating saddle height of pros (and a couple other things) for a while now; here is the summary:

Image

"Reach" is measured directly from the saddle tip to the handlebar (i.e., along the hypotenuse of the imaginary triangle), and "stack" is measured directly from the center of fork dropout to the top of the handlebar (again, along the hypotenuse). Saddle height is from center of BB to top of saddle measured along the seat tube.

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PostPosted: Wed Dec 19, 2012 4:22 am 
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HammerTime2 wrote:
If you just look at saddle height, you won't see the impact of upper vs. lower leg length on setback. All else equal, shorter lower leg (for a given saddle height) will tend to have more setback.

...If they adhere to KOPS, which more and more people are abandoning due to its irrelevance.


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PostPosted: Wed Dec 19, 2012 4:42 am 
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Whether or not KOPS is adhered to, upper vs. lower leg length is of paramount impact to setback.


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PostPosted: Wed Dec 19, 2012 4:57 am 
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I'd be much more interested in their centers of gravity in relation to the BB. I'd guess that two different riders with very different amounts of set back will be
similarly positioned over their BB in terms of fore aft.


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PostPosted: Wed Dec 19, 2012 8:07 am 
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HammerTime2 wrote:
Whether or not KOPS is adhered to, upper vs. lower leg length is of paramount impact to setback.

For what?


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PostPosted: Wed Dec 19, 2012 11:24 am 
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fa63 wrote:
I have been tabulating saddle height of pros (and a couple other things) for a while now; here is the summary:

<snip image>

"Reach" is measured directly from the saddle tip to the handlebar (i.e., along the hypotenuse of the imaginary triangle), and "stack" is measured directly from the center of fork dropout to the top of the handlebar (again, along the hypotenuse). Saddle height is from center of BB to top of saddle measured along the seat tube.


fa63, is the reach measurement you have from the saddle tip to the start of the handlebar, middle, or furtherest?

Cheers,
Ian


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PostPosted: Wed Dec 19, 2012 11:56 am 
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To the center of the handlebar.

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Posted: Wed Dec 19, 2012 11:56 am 


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