New version V8. Biomechanical & sizing & fitting spreadsheet

A light bike doesn't replace good fitness.

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beatnik
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Joined: Thu Aug 03, 2006 6:38 pm

by beatnik

I have no time to answer everything (father of 2 babies), and the s.s. needs you work on it with minor adjustments. Last post is the way to do it. Work on your bike measurements and feel the difference. It´s easier than it was for me, and the s.s. has years of work, research and development with thousand of riders.

Best regards.
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

by Weenie


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Giant DK
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Location: Denmark

by Giant DK

Capisce wrote:In connection with Giant DK measurement of saddle reference point.
1. Does this formula apply for purposely designed wider saddles? I am currently on a Specialized Toupe 143mm.
2. The Toupe is 27cm, compared to a reference Selle Italia saddle which is 28cm the reference spot is 1,5cm further from the nose on the Selle compared to the Specialized. Does this mean I should add the 1,5 to the recommended 9,4 setback?
3. Something does not add up in the spreadsheet or with my fit. I am currently on a 58tt, saddle 27cm, recommended stem length is 110mm which I currently run with a 8cm drop. I now have saddle to handlebar distance of 56cm, but setback of only 8cm. The spreadsheet recommends 9,4, but then my saddle to handlebar would be longer than recommended again. Shorter stem? I refuse to go shorter than 10cm.... If you add the proposed extra setback from point 2 above I should have a massive 2,9 more setback than at the moment and would need a 8cm stem to achieve the saddle-handlebar recommendation. This can't be right or is the top tube simply too long?
4. 90cm inseam 51 elbow-middle finger, what does this say about my body proportions? 189cm overall.


If the refference spot on a Selle Italia is 1,5cm further from the nose tip, the saddle should be placed 1,5cm further ahead to make the refference spot be at the same place in regards to the BB.
Technical editor at Cykelmagasinet Denmark

My Simplon Pavo II

L3X
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Joined: Wed Feb 25, 2009 8:39 pm

by L3X

Never mind...

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spaniardclimber
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by spaniardclimber

I've heard that lately 5-6cm bb-seat setback is being recommended for riding at high cadences, what do people think about this?

Ypsylon
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Joined: Wed May 24, 2006 6:25 pm

by Ypsylon

I think bb to nose of the saddle will tell you very little about where you are actually sitting and is therefore not very usefull.

Extreme example, but I think you get the point:

Image
"Nothing compares to the simple pleasures of a bike ride," said John F. Kennedy, a man who had the pleasure of Marilyn Monroe.

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beatnik
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by beatnik

Just few words to recommend this to everyone that can afford them (like SMP not cheap stuff). Just give them a try, you will never come back to a regular chainring. Regards.


http://www.rotorbike.com/nueva/ingles/r ... 130bcd.htm


About saddle nose- pedalier setback, it´s calculated with a 28 cm saddle, so it´s easy to substract your saddle length from the formula .If your setback is 8 cm for the nose, and your saddle length is 26 then (28-26)+8=10

back. :noidea: :smartass:
Last edited by beatnik on Mon Dec 28, 2009 6:28 pm, edited 2 times in total.
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

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beatnik
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Joined: Thu Aug 03, 2006 6:38 pm

by beatnik

lalahsghost wrote:I've used this spreadsheet to compare to my two road bikes' fittings before and they were close to being spot on.

Bought a Gary Fisher Cobia and directly went to the spreadsheet after ghetto-sizing everything after a few days of riding. Guess what? Nearly perfect fitting again!

I always think my comfort isn't in the numbers, but this can get me to a very close ballpark estimate before fine-tuning everything myself.


:up:
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

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beatnik
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by beatnik

I :unbelievable:
Last edited by beatnik on Mon Dec 28, 2009 6:28 pm, edited 1 time in total.
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

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beatnik
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Joined: Thu Aug 03, 2006 6:38 pm

by beatnik

Ypsylon wrote:I think bb to nose of the saddle will tell you very little about where you are actually sitting and is therefore not very usefull.

Extreme example, but I think you get the point:

Image


And that´s the case
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

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monkeymajik
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Joined: Mon Dec 14, 2009 2:09 am

by monkeymajik

beatnik your spreadsheet is extremely helpful thanks! I tweaked the setup of my current bike based on it and it feels much better.

If your torso/arm length is in un-usual proportion to leg length, what would you recommend as most important when sizing a new frame. Top tube length or seat tube length? Or something more complex.

Eg - I'm just over a 93 inseam with a 50cm forearm and am young and flexible. I am looking at a canyon ultimate CF frameset size 60 perhaps is a good compromise between appropriate seat tube/top tube? If I was sizing based on seat tube alone I would be put into a 62, but that would be a fair amount of reach. What would you suggest? Another manufacturer? :) I use compact bars

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beatnik
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by beatnik

You have a private :thumbup:
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

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beatnik
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Joined: Thu Aug 03, 2006 6:38 pm

by beatnik

Let´s make an example, as i told before saddle setback is calculated for a 28 cm saddle...

For the ISM ADAMO saddle pictured in previous posts:

http://www.ismseat.com/products_racing.htm

Perfect front setback (saddle nose to b.b. axis) (from s.sheet) : 8 cm
Saddle length= 24 cm

So the new setback for a 23 cm saddle would be

(28-24)+8= 12 cm

And another example for a longer saddle like ARIONE

http://www.fizik.it/catalog.aspx?subid= ... _brightred

P.S= 8 cm
Saddle length= 30

Setback : (28-30)+8= 6 cm

And another one for the spanish Duopower

http://www.duopower.com/index.php?lang= ... seccion=43


P.S= 8 cm
Saddle length= 17 cm



(28-17)+8=19 cm



It´s no so complicated. Nevertheless i´ll put this calculation in my next version.
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

Cobbles
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Joined: Sun Jan 03, 2010 4:18 am

by Cobbles

Beatnik-

Great system! I only have one question for you: how do you modify the saddle height if one is using Speedplay pedals? Given their low stack height, the saddle would need to be slightly lower but how much lower? :noidea:

Thanks,
Cobbles

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beatnik
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by beatnik

It´s not easy, because you must consider also your crankarm length, but the system is based in a 150º -155º angle for your knee, it´s better to feel it, because even your saddle padding is important.

S.P. stack height is around 10 mm and Look is 15 mm, so it´s not a big difference, but if you are so meticulous just low your saddle 5 mm :lol: .
Biomechanical spreadsheet. Sizing&Fitting.

http://weightweenies.starbike.com/forum ... 8e319d185b

Super_fast
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Joined: Tue Nov 01, 2005 9:36 am

by Super_fast

The difference is a lot smaller only 1-2 mm between all modern systems (SPD-SL, Time, Look Keo, Speedplay). With Speedplay compatible shoes the stackheight will be a few mm lower. When you come from Campa or Look Delta pedals the difference is quite large, they have a stack height of 27 mm.

by Weenie


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