# Top tube vs bike size



## yetidude (Dec 18, 2007)

Why is it that I hear that the top tube measurement is more important that the actual size of the bike? 
I'm 5'8 and I read in this forum that a small TCR is better for my size and the Giant website say I should ride a medium. Do they know something that we don't?
Thanks for your help


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## Guest (Nov 29, 2008)

Especially with today's sloping top tubes you may have stand over clearance on a frame with a top tube that is too long for you.


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## Aushiker (Mar 23, 2008)

yetidude said:


> Why is it that I hear that the top tube measurement is more important that the actual size of the bike?
> I'm 5'8 and I read in this forum that a small TCR is better for my size and the Giant website say I should ride a medium. Do they know something that we don't?
> Thanks for your help


Compact frames? Isn't effective top tube length more important? Sheldon Brown RIP has some insights on frame sizing which are worth a read in my view.

Regards
Andrew


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## robpar (Jan 26, 2008)

yetidude said:


> Why is it that I hear that the top tube measurement is more important that the actual size of the bike?
> I'm 5'8 and I read in this forum that a small TCR is better for my size and the Giant website say I should ride a medium. Do they know something that we don't?
> Thanks for your help


I've had the same issue and the answer is... It depends on what fit you are looking for.
For example, I'm 5 foot 10, the Giant chart says M/L (for TCR composite) BUT I needed the bars higher so my LBS suggested a large, with a top tube of 585mm vs 570mm (for the M/L); the large has about 1 inch longer head tube (the bars would sit about 1 inch higher) and I could put a stem that was 20mm shorter.
For my kind of riding: long, medium pace rides, NO racing, that fit has proven right for me.
If I were to race, I would probably have gone for the M/L 
So depending on the kind of riding you do, the smaller frame will provide a "quicker response", more compact aero fit, the larger frame gives you a more upright, more "comfy" fit.
I would decide based on the fit you want. Once your saddle height is determined, the frame size will set how far you have to reach (you can adjust easily your reach within 0-30mm depending on stem size) and how high the bars can go.
My guess is that a medium will give more flexibility to choose the exact fit you want.


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## XTR_Chris_XTR (Oct 4, 2008)

I am 1,74m and ordered a Giant TCR size S. Inseam 81, Seathigh 71,5 (BB to the top of the saddle)

At the moment my bike has a 54,5cm toptube, the giant hast 53,5cm. With a 120mm Stem it will be perfect for me!


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## yetidude (Dec 18, 2007)

Thanks for your replays. Good info here. I guess I could go for a M with a shorter stem like robpar said, I just don't like the small look on the TCR. Even though it could be a lot faster bike.
XTR Chris, what was your reasoning on a small with a long stem?

Thanks to all.


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## XTR_Chris_XTR (Oct 4, 2008)

1. At the moment my toptube is 54,5cm and i have a 110mm Stem. The Giant has 53,5 toptube. So with a 120mm Stem I will have nearly the same position as now.

2. Because of the sloping of the Giant it looks better if ne seatpost isnt't so short. 

3. With a longer seatpost proberly it will be easier to sale it in future

4. with the small frame the bike will react more directly.

5. S is lighter than M


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