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  #1  
Old 01-27-2013, 02:09 AM
esldude esldude is offline
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Stupid top tube tricks

Just wondering. Seems my favorite top tube measures happen to be right at my height divided by pi. Yep, height divided by 3.14159.

Just wondering how many other folks this happens to work for.

Now as an aside discussion it was not far from the square root of 10, but in the end seemed to be much more aligned with pi.

So height divided by pi, does it work for you or not?

Then there is the height minus inseam times .6 for top tube. Same result actually.

So what say you?
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  #2  
Old 01-27-2013, 02:22 AM
jtakeda jtakeda is offline
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Both don't work for me.

First calc leads to 54cm which is one cm off, I prefer a 55cm.

2nd calc leads to 51cm which is way too short.
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  #3  
Old 01-27-2013, 02:48 AM
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carlucci1106 carlucci1106 is offline
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Yuuuuuppp

165" /pi = 52.5, my desired TT
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  #4  
Old 01-27-2013, 01:22 PM
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fa63 fa63 is offline
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Doesn't work for me (gives 58 cm vs. 55-56 that I prefer).
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  #5  
Old 02-25-2013, 12:50 PM
Designatedbiker Designatedbiker is offline
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I'm 179cm/Pi= 56.979
I ride a 56cm Cannondale Supersix

I'm looking for a used Time RXRS and LBS tells me I'm Medium though according to your formula I'd be a Large...?
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  #6  
Old 02-25-2013, 02:17 PM
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donevwil donevwil is offline
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Didn't think this had a chance considering my height & torso to leg length ratio, but:

195.5cm / Pi = 62.2cm I run a 62 TT.

Wow !
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  #7  
Old 02-25-2013, 03:48 PM
Designatedbiker Designatedbiker is offline
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Quote:
Originally Posted by esldude View Post

Then there is the height minus inseam times .6 for top tube. Same result actually.

So what say you?
I'm not getting the same...

5'11" (71") - 32" = 39" x 0.6 = 23.4" how to convert back to cm?
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  #8  
Old 02-25-2013, 06:09 PM
esldude esldude is offline
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23.4*2.54=59.4cm

Of course height divided by pi would be a different number in your case 57 cm.

For what its worth, I did run into a custom builder who said a shortcut to get close he usually divides height by 3.1 which works for most people. So probably just a coincidence, but it isn't far off for a good many people. Though clearly not everyone.
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  #9  
Old 02-25-2013, 06:31 PM
thirdgenbird thirdgenbird is offline
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It's came out a little longer than I ride, but I also use a 130mm stem so it is well within reason.
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  #10  
Old 02-25-2013, 11:23 PM
avalonracing avalonracing is offline
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First thing I thought was, "God, you guys are geeks". Then two seconds later I was curious and was punching in number on my iPhone calculator.
As for the formula... Pretty damn close for me.
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  #11  
Old 02-25-2013, 11:32 PM
Anarchist Anarchist is offline
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Stupid top tube tricks

Quote:
Originally Posted by Designatedbiker View Post

.......... how to convert back to cm?
Really?
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  #12  
Old 02-26-2013, 07:59 AM
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William William is offline
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Hmmm, mine falls right on the money at 62.6.






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  #13  
Old 02-26-2013, 09:18 AM
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vav vav is offline
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Tt

Mine is spot on. 57.8 result and my bikes run TTs between 57.5 and 58.5. WoW!
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  #14  
Old 02-27-2013, 01:04 AM
Designatedbiker Designatedbiker is offline
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Quote:
Originally Posted by Anarchist View Post
Really?
Just being lazy, it actually turns out to be 59.436 cm, off by more!
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  #15  
Old 02-28-2013, 01:20 AM
idragen idragen is offline
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pretty cool but off by 30 cms haha
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