# Seattube length on a 54cm Madone Pro Fit?



## ping771 (Apr 10, 2006)

Anyone know what the length of the seattube from the center of bb to top of extended seatmast cap of the Madone Pro Fit 54cm frame? 

No one around me seems to have the 54cm pro fit in the bike shop. 

Thanks!


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## zac (Aug 5, 2005)

ping771 said:


> Anyone know what the length of the seattube from the center of bb to top of extended seatmast cap of the Madone Pro Fit 54cm frame?
> 
> No one around me seems to have the 54cm pro fit in the bike shop.
> 
> Thanks!


Your request isn't really easy to answer as the seat mast cap can be had in two different sizes.

For a 54cm Pro frame the frame stack is 52.5cm and the minimum (lowest) setting for the seat mast is 54cm but that is not the seat setting. You can then work back up based on your saddle and whatever mast you need.

HTH
zac


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## ping771 (Apr 10, 2006)

Zac,

Sorry, for not being clear. Let me re-ask the question as I don't think you answered it. What I meant is what is the length of the seat tube from center of bb to top of the seatpost (the top of the aluminum/steel colored seat post collar) on a 54cm frame? Trek does not give that measurement.

In other words, on pre-08 madones, a 54cm frame meant that the seat tube from center of bb to top of seat clamp was 54cm (center to top measurement). On the 08 madones, the seat post is extended a few cm in pseudo isp fashion. But Trek does not give a meaurement for this new "center to top" measurement.

Thanks.



zac said:


> Your request isn't really easy to answer as the seat mast cap can be had in two different sizes.
> 
> For a 54cm Pro frame the frame stack is 52.5cm and the minimum (lowest) setting for the seat mast is 54cm but that is not the seat setting. You can then work back up based on your saddle and whatever mast you need.
> 
> ...


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## PJ352 (Dec 5, 2007)

ping771 said:


> Zac,
> 
> Sorry, for not being clear. Let me re-ask the question as I don't think you answered it. What I meant is what is the length of the seat tube from center of bb to top of the seatpost (the top of the aluminum/steel colored seat post collar) on a 54cm frame? Trek does not give that measurement.
> 
> ...


If I'm reading your question correctly, you're applying a measurement used on bikes with a horizontal TT to one with a sloping TT. Your question is irrelevant in regards to fit, so it might be better for you to explain why you need this measurement. 

BTW, the equivalent for your pre '08 Madone measurement can be had by measuring from center of BB to the 'V' mark on the seatmast. It denotes the effective TT measurement. Someone with a 54cm Madone (can be pro or performance - both measure the same at that point) can get you that.


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## zac (Aug 5, 2005)

ping771 said:


> Zac,
> 
> Sorry, for not being clear. Let me re-ask the question as I don't think you answered it. What I meant is what is the length of the seat tube from center of bb to top of the seatpost (the top of the aluminum/steel colored seat post collar) on a 54cm frame? Trek does not give that measurement.
> 
> ...


Yeah, they don't because it is a meaningless measurement on the new Madones. The stack height is the more meaningful one. The clamp on the mast cap moves up and down along the seat mast as you adjust for your saddle height. If you fit a 54cm pre-08 Madone, you will fit a 08+ Madone in the same size. 

If you know your existing BB center to Saddle top measurement, then you can use that. Trek has the size ranges for the two different seat masts on their website and in their brochure.

For instance I always set for (172.5 cranks) my saddle top at 745mm from the spindle. I would fit a 54, 56, and 58cm Madone; But now I have to take into consideration my desired reach and drop. The 56cm Madone with a 100mm stem fits me and gives me my desired "reach" of ~522mm (modified reach from saddle nose to CL bars) with a drop of 115mm (level saddle top to CL bars at stem).

The stack height is more meaningful as it takes into account the two different frames Pro & Performance with the Performance being slightly less than 30mm taller in stack over a same sized Pro frame. The Pro frames match up to the geometries of the pre-08 Madones. Whereas the Performance frames are a tad more upright and eliminate the need for extended steerer and spacers or flipped up stems. Plus the Stack height is easy to correlate to reach and drop.

There is a Madone Geometry chart over at Trekbikes.com.

HTH
zac


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## PJ352 (Dec 5, 2007)

zac said:


> Yeah, they don't because it is a meaningless measurement on the new Madones. The stack height is the more meaningful one. The clamp on the mast cap moves up and down along the seat mast as you adjust for your saddle height. If you fit a 54cm pre-08 Madone, you will fit a 08+ Madone in the same size.
> 
> *If you know your existing BB center to Saddle top measurement, then you can use that. Trek has the size ranges for the two different seat masts on their website and in their brochure.*
> For instance I always set for (172.5 cranks) my saddle top at 745mm from the spindle. I would fit a 54, 56, and 58cm Madone; But now I have to take into consideration my desired reach and drop. The 56cm Madone with a 100mm stem fits me and gives me my desired "reach" of ~522mm (modified reach from saddle nose to CL bars) with a drop of 115mm (level saddle top to CL bars at stem).
> ...


Like this:
https://trekroad.typepad.com/photos/uncategorized/2007/06/05/2008_trek_new_mdaone_seat_height__2.gif


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## zac (Aug 5, 2005)

PJ352 said:


> Like this:
> https://trekroad.typepad.com/photos/uncategorized/2007/06/05/2008_trek_new_mdaone_seat_height__2.gif


That is the one.


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## ping771 (Apr 10, 2006)

Thanks guys, but what is "frame stack"? I see that on Trek's Madone frame geometry chart, but it is not clear to me what that is. I know it doesn't mean "stack height" as in headset height. Is frame set a difference or sum of two measurements? 




zac said:


> Your request isn't really easy to answer as the seat mast cap can be had in two different sizes.
> 
> For a 54cm Pro frame the frame stack is 52.5cm and the minimum (lowest) setting for the seat mast is 54cm but that is not the seat setting. You can then work back up based on your saddle and whatever mast you need.
> 
> ...


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## ping771 (Apr 10, 2006)

Nevermind. I found out what frame stack means. 
Here: 
http://trekroad.typepad.com/trekroad/2007/05/designing_the_n.html

Thanks for all your help guys.



ping771 said:


> Thanks guys, but what is "frame stack"? I see that on Trek's Madone frame geometry chart, but it is not clear to me what that is. I know it doesn't mean "stack height" as in headset height. Is frame set a difference or sum of two measurements?


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## PJ352 (Dec 5, 2007)

ping771 said:


> Nevermind. I found out what frame stack means.
> Here:
> http://trekroad.typepad.com/trekroad/2007/05/designing_the_n.html
> 
> Thanks for all your help guys.


You got it! :thumbsup: 
Just keep in mind that frame stack doesn't really come into play until you've got your saddle height established. It is a good point of reference, though in determining which bikes will have greater or less saddle to bar drop - all else being equal. IMO, it would be good for other manufacturers to join in on this (sort of) trend, but to date only Trek and Cervelo seem to see the value in it. Until then I guess ya gotta bring a tape measure along to compare other brands of bikes. 

EDIT: For the record, note that frame stack and stack height _are not _reach.


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## Falling Snow (Apr 2, 2008)

*A Word of Caution*

I'll just add one thing, otherwise I think everything else was covered already... 

If you are on a size where you're at the upper limit of the adjustable height of the seat cap (especially if you're already using the taller cap) you may have issues if you want to change your saddle. The graphic of the chart that was provided earlier in this thread assumes you're using the stock seat. I changed mine and my new saddle has a much lower profile than the stock one. Thus, in order to get the same saddle height, I had to raise the cap significantly (around 2cm if I remember right). Given my saddle height, had I been on a 52cm instead of the 54cm (that I have) I'd have been in trouble. YMMV.


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