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 Post subject: Re: An analysis of drop
PostPosted: Fri Mar 29, 2013 3:23 pm 
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Joined: Thu Feb 14, 2008 7:19 pm
Posts: 900
Location: South Carolina
KWalker wrote:
djconnel wrote:
stella-azzurra wrote:
Unfortunately cycle fit changes with time and age.


This is part of the reason yoga is so important. Riding's an unnatural position, as is sitting at a desk: it's important to unwind, literally. Also, when getting older, I think muscles knot up more readily. This is why massage becomes more important. It's particularly an issue with me because I ride a lot with a backpack (when commuting).


Yoga is not that important. Its an excuse for sedentary people to pretend that they're doing exercise so they feel better about being functionless human beings. I did it for a while and found that at first it was ok, but in the end no better than a simple set of static and dynamic stretches that I could do in my own home for half the time. Combined with studies that demonstrate that it actually does not improve functional flexibility and has a high potential for injury (see this article for examples: http://www.nytimes.com/2012/01/08/magaz ... wanted=all" onclick="window.open(this.href);return false;) I don't see it being necessary or important for anyone, let alone cyclists.

I will say, however, that some of the more traditional asthanga or less extreme/more dynamic vinyasa classes are your best bet since they at least provide relaxation and combine static and dynamic stretching.


Don't forget that Yoga is also great for the pants!!

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 Post subject: Re: An analysis of drop
PostPosted: Sun Mar 31, 2013 10:18 pm 
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Posts: 98
HUMP DIESEL wrote:
[quote="Strange. I understand what you are saying, but drop affects reach too. The more drop you have, the longer your reach is in a given position. They go hand in hand, which is why riders tend to sit either lower and longer or high and short. I would think high and short would be suboptimal on a standard-geo. road bike, because, in most cases, the frame was not designed to be ridden that way, and a lower center of gravity usually results in better handling.


Drop effects actual reach, but not the reach in a linear way from the bottom bracket. It affects how far you "Reach" to put your hands in the drops. I know we got onto Steve Hogg for a bit, but a lot of what he talks about is actually good common sense. He talks about having the minimal number of muscles recruited for stabilization. That makes perfect sense, in the fact that if you upper body is relaxed, due to not being in a position that requires recruitment of smaller stabilizer muscle of the abdomen and lower back, you are able to breathe more freely and in turn produce more efficient power. Note, I did not say more power, just more efficient power.

HUMP[/quote]

Not sure what you are saying by "linear" reach. If you run 6 cm of drop and a 12 cm stem and then increase that drop to 10 cm, you will need a shorter stem, as you are reaching farther. Sitting lower on a given frame is better for handling -- to a point of course. Bikes were designed to handle right with the rider in a certain position, if we start moving away from that too much, handling will suffer.


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 Post subject: Re: An analysis of drop
Posted: Sun Mar 31, 2013 10:18 pm 


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 Post subject: Re: An analysis of drop
PostPosted: Mon Apr 01, 2013 7:10 am 
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Posts: 445
Location: Russia, Moscow
Colonia wrote:
If you run 6 cm of drop and a 12 cm stem and then increase that drop to 10 cm, you will need a shorter stem

Yes, reach to handlebars will increase, however the difference is pretty small, so you might get away with keeping your current stem just fine. For example, for your scenario and initial distance of 70 cm from mid-saddle to handlebar, this distance will increase only about 5 mm.


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 Post subject: Re: An analysis of drop
PostPosted: Mon Apr 01, 2013 1:57 pm 
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Location: Bay Area
By reach I often refer to the way a frame designer would- from BB to the center of the bars. I refer to height as stack. So yes, decreasing stack also increases how far you have to reach, but to keep it simple I separate the two. When I gave the example above, my stack did increase when my reach did as well- by over 2cm at one point (which as you noted reduced reach), however, the distance from saddle tip to bars was relatively similar. This was meant to say that I did less well with having my bars further out than further down.

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 Post subject: Re: An analysis of drop
PostPosted: Mon Apr 01, 2013 9:11 pm 
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Location: San Francisco, CA
The bars move down by 4 cm. That means they move outward by (4 cm) cot(HTA) = 1.2 cm. Additionally they've moved down by 4 cm. If the shoulder position is fixed, the stem would then need to be at least 1.2 cm shorter. But since the arms swing at an angle, slightly shorter, depending on how high shoulders are above bars.

I looked at changing setback here:

Image

This was done with a photo I took of myself. Unfortunately the relevant dimension is missing, but I'd want to keep the length from shoulder to hand contact the same, so that requires moving hands closer to BB (horizontal axis).

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 Post subject: Re: An analysis of drop
PostPosted: Tue Apr 02, 2013 7:07 am 
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Oops, you are right, djconnel, I forgot about head tube angle. So the actual difference in distance from saddle to handlebar will be around 1.7 cm.


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 Post subject: Re: An analysis of drop
PostPosted: Tue Apr 02, 2013 8:52 am 
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stella-azzurra wrote:
Man does Steve Hogg milk it to the full extent of the definition.

Lets see:

Cycle fit = $720 AUD plus any parts required.
Frame Fit = $420 AUD plus any parts required.
Final Fit = $300 AUD plus any parts required.
Video Fit = $250 AUD + $135 AUD for each additional*
*Typically 2 to 3 videos are necessary for video clients to be a happy.

http://www.stevehoggbikefitting.com/cyc ... t-options/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Bend over and take it like a man! :unbelievable:

You can kinda say he lives high on the Hogg :lol:


Not that Hogg needs or asks for any defending but the prices are very reasonable when the time is factored in. My fitting with Mr Hogg took ~6hrs to complete, just over $100 per hour, 'bout right for a one on one consultation with a professional. Things do get whacky with Mr Hogg but how many people there make a full time living from bike fitting alone? He is laissez-faire with his techniques, if it doesn't work, he doesn't use it If it does work, he'll use it, even if it is a placebo effect. And if it is placebo effect it's one of the best I've had. One issue I had has been gradually improving over the ~3 weeks since the fit. Change in fit requires adaptation. This has now brought to the fore a different issue which the first was masking. This will then be corrected.

$720 is a bit of cash. However, compared to the $3k frame and $2k drive train and $3k wheels... well it's small change really. YMMV.

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 Post subject: Re: An analysis of drop
PostPosted: Tue Apr 02, 2013 11:03 am 
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slyboots wrote:
Oops, you are right, djconnel, I forgot about head tube angle. So the actual difference in distance from saddle to handlebar will be around 1.7 cm.


Yes, just as I said. A change in stem length would be needed.


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 Post subject: Re: An analysis of drop
PostPosted: Tue Apr 02, 2013 11:18 am 
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Agreed. :beerchug:


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 Post subject: Re: An analysis of drop
PostPosted: Tue Apr 02, 2013 1:28 pm 
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Image
I added the relevant dimensions to my plot.

Using this plot, I want to keep the net distance from shoulders to hand the same.

If I have a hypotenuse with dimensions (x, y), and I change y to y+∂y, I want to change x to x - ∂x such that (x - ∂x)² + (y + ∂y)² = x² + y² .

To first order this is -2 x ∂x + 2 y ∂y = 0, or ∂x = (y/x) ∂y

So in this case, I increased drop by 4 cm. I then shorten a -17deg stem by 1.2 cm (HTA=73 deg) to bring them back under where they originally were just 4 cm lower. From the plot of my body, I then need to bring them an additional (4 cm)(0.531/0.554) = 3.8 cm closer (to first order).

So I get a net shortening of the stem by a total of 5 cm to keep the shoulder position the same and the arm length the same.

Did I make a mistake here?

Of course if I'm lowering my bars I probably want my shoulder position lower, otherwise I wouldn't lower my bar.

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 Post subject: Re: An analysis of drop
PostPosted: Wed Apr 03, 2013 3:19 pm 
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Location: Tucson, AZ
A small update to help visualize Gilbert's position on both bikes.

Here are the data comparing each bike, save for little things not listed in geo charts like SLR01 wheelbase or BB drop and fork rake... I just guessed. I also guesstimated the heights for spacers and cone spacers from Huang's photographs:

Image

An overlay of each bike (BMC in red, Canyon in green):

Image

And a close-up of the front end:

Image


Last edited by AGW on Wed Apr 03, 2013 3:29 pm, edited 2 times in total.

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 Post subject: Re: An analysis of drop
PostPosted: Wed Apr 03, 2013 3:20 pm 
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Location: Tucson, AZ
The position doesn't look as crazy in wire frame as it does on TV :D


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