Need advice on frame size

Discuss light weight issues concerning road bikes & parts.
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poppiholla
Posts: 480
Joined: Wed Aug 03, 2011 1:18 pm

by poppiholla

I am thinking about a Pinarello Dogma 65.1 think 2 or a Colnago C59 frameset to replace my 8 years old Storck C1.1 frameset. I am 186cm long. I have long arms and legs but relatively short thighs. For a Cyclist I am pretty flexible but I haven't got a sixpack anymore so I can't sit as deep as the pro's.
I already have a Specialized Tarmac Sl4 in size 58 with a 110mm 6 degree stem (25mm spacers). My saddle height is 79cm. I need a zero setback seatpost on the Tarmac to have an optimal power transfer. I really love the Tarmac and the fitting on the Tarmac feels correct.
The Storck C1.1 has a top tupe lenght horizontal of 57.5cm and I use a 120mm 6 degree stem (33mm spacers). I have a Ritchey seatpost with25mm setback. The fitting on the Storck feels also correct, but I need more spacers then on the Tarmac because of the headtube lenght. I can also use a 25mm setback on the seatpost. I find a seatpost with 25mm setback more beautiful then a seatpost with zero setback.

The Question: Which framesize do I need for a Colnago C59 slooping taking the above information into account? I think I need the 56s. Correct?
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Which framesize for a Pinarello Dogma 65.1 Think 2? The Pinarello is a traditional frameset with a horizontal top tube. I think that I need a CC 57.5 with a toptube lenght of 57.5 and a headtube of 179mm. Correct?
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Thanks for your help!

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WMW
in the industry
Posts: 889
Joined: Sun Jul 29, 2012 2:59 pm
Location: Ruidoso, NM

by WMW

You need to match up the xy dimensions of your saddle and bars relative to the bottom bracket. Without these current dimensions you can't really get started.
formerly rruff...

by Weenie


poppiholla
Posts: 480
Joined: Wed Aug 03, 2011 1:18 pm

by poppiholla

Can you explain it a little bit more? Why isn't the information that I gave not enough? I want to understand how the geometry work.
I found some more information of my body fitting. I don't know exactly what I am looking at. I got it from the shop where I bought the Tarmac but I never paid attention to it until recently.
Image

shimmeD
Posts: 443
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

Calculating Reach and Stack using your fit chart: using http://www.csgnetwork.com/righttricalc.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Step 1. Vertical distance between top of seat and bb centre using sides 233 (seat setback) and 788 (seat height) is 752.76, and seattube angle is 72.8deg.
Step 2. Calculate Stack as 752.76 less 83 drop = ~670. Note that this is top of seat to centre of bars. (Eg frame Stack is close to 629 if stem stack is 42 and headset stack is 20)
Step 3. Using 738 and 83 drop, horizontal dist between seat centre (where is this seat centre? This is why I use seat rails centre) and handlebars centre is 733.32.
Step 4. Calculate Reach as 733.32 less 233 seat setback = 500.32. To get frame Reach you can subtract stem length eg 490 if 110 stem

You need a little bit of maths to check from geometry charts whether you can get your seat and handlebars where you want them.

So according to my calculations you could pick a 560 Dogma, and try to get your bars raised 60mm. :smartass:

My versions of Setback, Stack and Reach are:
Setback: Horizontal distance between centre of seat rails (easy to mark and set this point with a little piece of electrical tape etc) and vertical line of bottom bracket centre.
Reach: Horizontal distance between centre of seat rails and centre of handlebars clamp.
Stack: Vertical distance between bb centre and centre of handlebars clamp.
Seat height: Better (for me) to use vertical distance between bb and centre of seat rails. If measuring along seat tube you have to be mindful that the seat tube on your frame may not be centred over the bb.
Less is more.

poppiholla
Posts: 480
Joined: Wed Aug 03, 2011 1:18 pm

by poppiholla

Thanks Shimmed, but I find it difficult to understand it completely. Do you mean I can pick a 560 Dogma and then use 60mm of spacers? If so that is out of the question, because I want no spacers at all in the most ideal situation.

shimmeD
Posts: 443
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

The best thing is to try out the frame/bike at a bike shop, with your current best bike AND a knowledgeable shop mechanic/assistant.

The maths say that you'll need to raise your bars 60mm, with a stem with rise and/or spacers on a Dogma 560.
Less is more.

by Weenie


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