Once more, trendy small frame size



rubencito30

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Jan 4, 2006
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Hello guys,
I have been doing some research about frame sizes lately. I'm discovering a trendy leaning towards smaller frame sizes. In professional racing the big guys are using small frame sizes and very long seat post and stems (140mm).
Please go to this page and see what the pros are riding sizes ranging from 49 to 56.
http://www.cyclingnews.com/tech/2005/probikes/

Do any know why does this has any advantage?

Rubencito Specht
 

ScienceIsCool

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Jun 25, 2006
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I can think of three reasons for top using "small" frame sizes. The biggest reason is to get a comfortable saddle to bar drop distance. On a bigger frame the headtube would be longer and this would be tough to achieve. Another reason is that a smaller frame is stiffer than a large one. And lastly, a smaller frame is lighter, though this would not be a big consideration for a pro.

John Swanson
www.bikephysics.com
 

bobbyOCR

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Aug 31, 2005
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Another reason is alot frames are compact. This adds a few cms to the seatpost. Also, alot of the aluminium frames are custom geometry (not sure about monocoque carbon. I don't think companies would go that far) and pros specify the shorter HT and TT so they can use the long stem (handling) and get the saddle-bar drop. Have a look at Cunegos cannondale. It has a tiny HT.
 

hd reynolds

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Nov 15, 2005
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rubencito30 said:
Hello guys,
I have been doing some research about frame sizes lately. I'm discovering a trendy leaning towards smaller frame sizes. In professional racing the big guys are using small frame sizes and very long seat post and stems (140mm).
Please go to this page and see what the pros are riding sizes ranging from 49 to 56.
http://www.cyclingnews.com/tech/2005/probikes/

Do any know why does this has any advantage?

Rubencito Specht
I think its just fashion. Have a guy win the tdf on a penny farthing and every average joe will go gaga with penny farthings.
 

Bro Deal

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Jun 26, 2006
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hd reynolds said:
I think its just fashion.
Ditto.

Back in the days when everyone rode steel and frame flex was truly a concern, the pros rode larger frames. Nowdays with oversized tubes frame flex is not a problem unless the frame designer wants it that way, so I don't buy into the frame flex argument. The weight saved is minimal, so I don't buy into that either. The only valid argument I can give credence to is getting a greater saddle to stem drop.
 

HUMP DIESEL

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Jun 11, 2007
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Alright, I am going to chime in because noone has given the answer that I think can explain all of this.


The frames fit better. I myself have been on more frames trying to figure this out and just like the first poster, I started doing research, and cyclingnews has been great for this because they give the dimensions of the set-up.

What I found with comparing someone of my size, is that:

#1- The saddle sits back farther than the KOPS would recommend.

#2- The front end of your body is resting on bone structure and not realiant on muscle fiber that can and will get tired and start to hurt.

#3- The frames are indeed stiffer and lighter.

#4- I know for a fact that all Team CSC riders ride standard geomtry, and that they will send you a list of all riders on that team and their frame sizes.


I ordered my team frame based off the research that I had done on this subject. I did not go to the extreme, I went one size smaller than what I had been recommended to ride.

I can tell you that my first part of this season was great, with top 3 placings and more wins than last season, and I still have half a season left. I have the points to upgrade to Cat2, so when I get a team that will offer me equipment I am going to delve into this even more and possibly go one more frame size down. I crashed in the last stage race I did and bent the top tube on my smaller frame which made me have to go back to my bigger spare frame and I can tell you it feels like **** compared to the smaller frame, I cannot get right on it.

A couple of examples:

Dave Zabriskie-5'-11' tp 6' He rides a 56. Most would put him on a 60

Carlos Sastre-5'-8 he rides a 51, most would put him on a 54 or 56 (I am speeking from experience here, because he is my height)

Luca Paolini-5'-8" He rides a 50cm Cannondale System 6, I emailed Cannondale and verified this one, and it is standard geometry.

Just something to think about.

HUMP
 

melslur

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Oct 31, 2005
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HUMP DIESEL said:
A couple of examples:

Dave Zabriskie-5'-11' tp 6' He rides a 56. Most would put him on a 60

Carlos Sastre-5'-8 he rides a 51, most would put him on a 54 or 56 (I am speeking from experience here, because he is my height)

Luca Paolini-5'-8" He rides a 50cm Cannondale System 6, I emailed Cannondale and verified this one, and it is standard geometry.

HUMP
I'm 5'8" and bought a 54cm. I was thinking about a 52 and was told it's too small. (I think 53 would have been ideal).

One question to consider: are the pro's heights their real heights, or do inches get added for ego? Just looking at the seat heights, it does seem to confirm that the pros ride smaller frames and hence that their heights are true.
 

artemidorus

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Mar 10, 2004
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HUMP DIESEL said:
#2- The front end of your body is resting on bone structure and not realiant on muscle fiber that can and will get tired and start to hurt.
Explain point 2 for me?
 

HUMP DIESEL

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Jun 11, 2007
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artemidorus said:
Explain point 2 for me?
Point two is as such, your body is made to support itself with the least amount of energy expenditure by using the bone structure, not the musclular tissue. In this since, a position that allows your arms and shoulders to act as support mechanisms and not balast, would appear to be better.

I am not a physiologist, but I have tested this. Take for instance, if you are stretched up and outward, you are causing your neck, shoulders and tricep muscles to do the work of support your upper body from falling over. Over a period of time, be it hours or minutes, depending on your conditioning, you will either start to hurt or fall over, which ever comes first.

If on the other hand you come back toward you and down, the structure of your bones is supporting the weight, you muscles are relaxed and they do not tire as fast which leaves more energy to do what you need to do and that is pedal.

I hope that explained it a little better, I was trying to think of an example other than cycling that would allow you to feel this difference, but I cannot right off the top of my head.

HUMP
 

sogood

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Aug 24, 2006
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HUMP DIESEL said:
Point two is as such, your body is made to support itself with the least amount of energy expenditure by using the bone structure, not the musclular tissue. In this since, a position that allows your arms and shoulders to act as support mechanisms and not balast, would appear to be better.

I am not a physiologist, but I have tested this. Take for instance, if you are stretched up and outward, you are causing your neck, shoulders and tricep muscles to do the work of support your upper body from falling over. Over a period of time, be it hours or minutes, depending on your conditioning, you will either start to hurt or fall over, which ever comes first.

If on the other hand you come back toward you and down, the structure of your bones is supporting the weight, you muscles are relaxed and they do not tire as fast which leaves more energy to do what you need to do and that is pedal.

I hope that explained it a little better, I was trying to think of an example other than cycling that would allow you to feel this difference, but I cannot right off the top of my head.
The issue here is, by rigidly propping yourself up with your bone structure, you are also converting yourself to be part of the bone shaker and get hit by every irregularity on the road and get tired out. Muscle support provides significant amount of damping and can actually lessen the stresses.
 

Skoorb

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Jan 9, 2007
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sogood said:
The issue here is, by rigidly propping yourself up with your bone structure, you are also converting yourself to be part of the bone shaker and get hit by every irregularity on the road and get tired out. Muscle support provides significant amount of damping and can actually lessen the stresses.
It will not be possible, generally, to have a totally rigid/straight arm. There will still be impact-taking angles, but the leverages will be better.

I am 5,11 and on a 56 right now and it's simply too big. If I want to get in the drops I'm stretched out like somebody on a rack.

Fashion is not a valid reason why a pro, who's livlihood depends on his performance, is getting a smaller frame. Maybe the frame is better, maybe it's not, but he's not choosing it over fashion.

I imagine a big reason they may want smaller is for the same reason a tri bike often fits small and on a smaller road bike their positioning may be better when they want to get down out of the wind.
 

HUMP DIESEL

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Jun 11, 2007
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Skoorb said:
It will not be possible, generally, to have a totally rigid/straight arm. There will still be impact-taking angles, but the leverages will be better.

I agree with this, that it will not put you in a complete rigid state, but the degree at which your arms have to bend is lessened, you will naturally bend your arm.

I do not think it is fashion either, I think there is something to this. I think a lot of the time that a bicycle retailer will sell something close because that is what they have....How many times do you ever hear...I tell you what instead of that 54, let's order you a 52, and let me sit on that inventory another month...

You will not hear that, they are in the business of selling bikes, and the fitting is just to get the bike out the door, from there it is our responsibility as a purchaser to make sure it works. That is where you get into buying frames and buiding them up.

I started out, by recommendation from the LBS on a 56, with a 110mm stem...I am 5'-8" This bike was too big, and I never got comfortable on it no matter what I did.

My next bike was s 54, it felt somewhat better, but still not perfect.

The last bike I got was a 52 and it felt better than any other bike I have ever had. I am now going to sell some of the other frames to get even a smaller one to try.

HUMP
 

knonfs

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Oct 2, 2003
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I wonder how this work on the Giant TCR bikes, and their Small\Medium\Large frames measurements :(

When I bought my TCR, per my inseam (I am 5'55) I was right in between the small size and medium size frame. At the last minute I ended yp going with the medium size frame. I always wondered if I should've gone with the SMALL size frame...
 

Skoorb

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Jan 9, 2007
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I always wondered if I should've gone with the SMALL size frame...
Remember, though, you can always change the specs on a bike to fit, within reason. My 54 just came yesterday and though I am sure it's better than a 56 for me, I find that I have to use ALL of the allowed length in the seat post to get the seat height where I want it. I do not have to do that with a 56, but a 56 would stretch me out. I could always have gotten a shorter stem with a 56, or in this case keep the 54 and get a longer seat post, if I felt that necessary.

I think seat posts are probably putting a bit of buffer room in anyway and I'm not too heavy at 170, so not too worried about stressing its tolerances :D
 

knonfs

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Oct 2, 2003
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Skoorb said:
Remember, though, you can always change the specs on a bike to fit, within reason. My 54 just came yesterday and though I am sure it's better than a 56 for me, I find that I have to use ALL of the allowed length in the seat post to get the seat height where I want it. I do not have to do that with a 56, but a 56 would stretch me out. I could always have gotten a shorter stem with a 56, or in this case keep the 54 and get a longer seat post, if I felt that necessary.

I think seat posts are probably putting a bit of buffer room in anyway and I'm not too heavy at 170, so not too worried about stressing its tolerances :D


I hear you, I have replaced the sterm to a shorter one, and have adjusted the saddle to its "proper" place; however I still fell like I am stretching when ridding on the brake\shifter hoods!