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  #31  
Old 03-20-2013, 02:39 PM
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Close, I got 60.6, and I usually run a 59-60 depending, but I could certainly fit a 60.6, you just don't see that size on the used market that often.
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  #32  
Old 03-20-2013, 04:40 PM
esldude esldude is offline
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Quote:
Originally Posted by tv_vt View Post
It's not bad for an estimate. Mine came out a little longer than I run now, but would've been closer 10-15 years ago.

Need a second factor in equation that takes into account age or something related to flexibility. Like this:

Height in cm (inches x 2.54) divided by Pi, then subtract 1 cm for every decade your age is above 30-39 (eg. 40-49, subtract 1cm; 50-59, subtract 2 cm,...)

Just tossing things around.

Wonder, too, if you should subtract a cm or 2 if you are female, since torso/leg ratios seem to be different for many women.
Not a pro fitter by any means. But I haven't found myself shortening the top tube as I age/or loose flexibility. I have found I need a touch taller headtube. Is it common to shorten the top tube for reduced flexibility?

I do suppose as you grow a touch shorter with age there would be a tiny adjustment using this formula. Average height loss is said to be 1 cm per decade past age 40. So using this formula you would perhaps get a one cm shorter toptube by age 70. I suppose this would make this formula a bit better than the Lemond formula based upon inseam because your leg length doesn't change with age.
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  #33  
Old 03-20-2013, 05:13 PM
ultraman6970 ultraman6970 is offline
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The whole body shrinks with age, besides flex issues.
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  #34  
Old 04-09-2013, 08:53 PM
rustychisel rustychisel is offline
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hmmm, 180cm = 57cm TT.

not quite, I used to ride that or 56, but now prefer 55cm, perhaps being in my sixth decade.
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  #35  
Old 04-10-2013, 11:31 AM
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Gives me a tt that's ~1.5 cm longer than I ride
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  #36  
Old 04-17-2013, 08:24 PM
gregblow gregblow is online now
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Originally Posted by greggblow View Post
It's 2cm longer than I ride. Uh oh. Anyone have a 56 I can try?
I bought a 56 and love it!! been on 54's for a while.
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  #37  
Old 05-21-2013, 08:16 AM
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Quote:
Originally Posted by esldude View Post
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?

55tt * 3.14159 = 172.79

spot on!
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  #38  
Old 05-29-2013, 01:33 AM
esldude esldude is offline
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So far it looks intriguing.

My interpretation of replies is 16 say it is spot on or darn close, 7 say close not quite, and only 1 says way off. So it sounds reasonable for 23 of 24 in most optimistic terms. Seems right on for 2/3's and close for almost another third.

For someone not experienced in such matters, sounds like height divided by pi would be reasonable starting point in these days of sloped top tube frames.

And for you 7 guys riding close, but not quite frames, how do you know you aren't on the wrong size? Yes, I am being funny with it a bit. But a centimeter and half or less can easily be altered with stem length.
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  #39  
Old 06-05-2013, 10:18 AM
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Stupid top tube tricks

190.4cm/pi = 60.2cm
I've been on 59/59.5cm TTs and now that I'm logging more miles in the drops mixed with core strength workouts, and a regular post-ride stretching regimen, I'm becoming more flexible with better breathing in the drops and actually recover more quickly there now than on the hoods! I think my bars are now too high and will be trying a longer stem affer trying the bars 5mm lower if it goes well.
Essentially, a longer top tube may be in the future, thanks for the fun trick!
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  #40  
Old 06-05-2013, 10:47 AM
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194.31 / pi = 61.9.

I run 59 with 120 stem, 60 with 110 stem and 60.5 with 100 stem.

Perhaps my stems are too long.
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  #41  
Old 06-18-2013, 07:19 AM
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Re: Stupid top tube tricks

Spot on for me. Weird. Lemond = outdated
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  #42  
Old 06-18-2013, 09:08 AM
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Using the formula I get 55.7 for me. My current bikes are 53.5 but run 130 stems. My first bikes were 56cm w/ 100/110 stems. I had less knowledge about bike fit back then and it looks like I have even less knowledge now...
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  #43  
Old 06-18-2013, 09:18 AM
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Stupid top tube tricks

Spot on w a 120 stem, assuming 73 x73 sta/hta. Change the angles and the top tubes change.

Len


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  #44  
Old 06-20-2013, 07:48 AM
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Quote:
Originally Posted by Len J View Post
Spot on w a 120 stem, assuming 73 x73 sta/hta. Change the angles and the top tubes change.

Len


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And you wanted me to drive out to Tom Kellogg. All I needed to do was divide by pi.
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  #45  
Old 06-21-2013, 01:53 PM
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Kirk Pacenti Kirk Pacenti is offline
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Oh, I was thinking of the wrong sort of 'tricks'...

Anyway, the Pi trick comes pretty darn close for me too.

Cheers,
KP
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