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PostPosted: Fri Sep 14, 2012 6:34 pm 
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Joined: Sun Dec 27, 2009 10:55 pm
Posts: 108
Location: Honolulu
Heel height variation at the bottom of the stroke, throws formulas to the wind more than anything else. Well, that and the actual cycling inseam measurement.


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PostPosted: Sat Sep 15, 2012 11:29 am 
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I have my saddle at 72.5 cm.

Values from fit calculators are only a starting point. Even professional bike fitters have to start somewhere. After an initial fit assessment and a trial ride, the fitter may adjust the saddle height (among other things) depending on the rider's feedback.

As some of the posters have pointed out there are a lot of variables that come into play - inseam measurement being only one (primarily IMO).


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Posted: Sat Sep 15, 2012 11:29 am 


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PostPosted: Sat Sep 15, 2012 12:52 pm 
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Joined: Wed Jan 18, 2012 7:09 pm
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Have an inseam of 80cm so slightly higher than the OP and ride right around ~71.4cm or so. Originally had 2 different fitters set it at 73cm and couldn't figure out for the longest time why my back and butt hurt so much. It felt like I couldn't bend over or relax forward at all. Finally went about adjusting it myself and settled around ~71.4cm with a good big of set back that allows me to bend easily and comfortable.

Also, now a saddle that used to be insanely painful *Arione* is now completely tolerable!

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PostPosted: Sat Sep 15, 2012 6:54 pm 
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digitalnorbs wrote:
I know we are all different, but I was just wondering how high are others seat with that kind of inseam=)

I for the life can seem to go over 70 cm, with around 8 cm seatback, other wise I have lots of pain in my lower hamstring and the outside of my knee?

Multiply inseam by .883. From there you can go about 1.5-2 cm lower or higher.

8 cm setback seems very extreme for your inseam, unless you have very long femurs. Use the KOPS method to get a baseline on your setback. Drop a plumb line from your tibial tuberosity when the cranks are horizontal and level. Plumb line should bisect pedal spindle. From there you can be about 2cm back, if you prefer the extra setback.


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PostPosted: Sun Sep 16, 2012 3:02 am 
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I'm beginning think that my hamstrings are the weakness here, I dropped my seat to 68.5 and my left foot is almost even with the right side as for the symmetry goes.
I'm will try 68 tomorrow, the big setback helps me with comfort for sure, never been this comfortable on a road saddle before.

gSent from my iPad using Tapatalk HD


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PostPosted: Sun Sep 16, 2012 3:52 am 
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Joined: Thu Sep 13, 2012 3:57 am
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The idea behind the saddle height and setback is pedaling efficiency, and obviously comfort as well. Your pedal stroke is affected by the frame geometry - specifically the seat tube angle, and crank length. Your position on the bike affects your biomechanics and would certainly cause discomfort (or worse pain) if not set up properly.

It's hard to diagnose your exact problem without any idea of what you're running.


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PostPosted: Sun Sep 16, 2012 4:30 am 
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It's a 2010 cervelo rs in 54, 172.5 cranks, 110mm set at -6, 15mm of spacers from top of headtube to stem, hope this helps

from my iPad using Tapatalk HD


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PostPosted: Sun Sep 16, 2012 9:58 am 
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For what its worth:
Inseam = 80cm (bare feet)
Seat height = 71cm (centre BB parallel to seat tube, Arione saddle)
Cleat/pedal stack = 12mm
Shoe stack idk but ~10mm I guess.
Cleats mounted as far back as they will go.
STA = 74°, setback 25mm
Crank length 172.5

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PostPosted: Sun Sep 16, 2012 1:12 pm 
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digitalnorbs wrote:
It's a 2010 cervelo rs in 54, 172.5 cranks, 110mm set at -6, 15mm of spacers from top of headtube to stem, hope this helps

from my iPad using Tapatalk HD


*Disclaimer: I am in no way a professional bike fitter. It's just an interest of mine and a way to help my riding buddies get the most performance from their bikes. My observations and recommendations are not to be taken as 100% correct.

Based from your inseam measurement, I used anthropomorphic data from a study to "guestimate" your physical measurements. And taking your bike's (Cervelo) frame geometry I plugged these into an anatomical model.

My observations from the model:
- The 54 frame size is good for you. TT + stem length gives a riding position on the bars at a comfortable upright 47°.
- Saddle height of 72 cm to 73 cm is optimal. Your legs still do not reach full extension at this height.
- A saddle setback of about 2 cm to 3 cm is good to get your "knee (roughly) over the pedal spindle".

Gathering from your previous posts and comments from the other posters, this is what I think:
- Sore lower hamstrings and pain at the outer knee (where the hamstrings attach) is a sign of leg overextension, probably due to a high saddle.
- You might have a leg length discrepancy, taking your left leg giving more power than the right when the saddle is raised.
- Your saddle height lowered to 68 cm feels alright with the pedal at the 6 o'clock position, but feels awkward at the 3 o'clock position. Moving your saddle back by 8 cm feels better. Might be you have a longer femur-to-tibia ratio than normal?
- The wide saddle might be causing you to overreach on the downstroke. The 155 mm saddle is usually for women who have wider pelvises than men. Have your pelvis width checked to determine the correct saddle width for you.

Hope this helps.


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PostPosted: Sun Sep 16, 2012 8:37 pm 
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guys, thank you again, I know, no one is a fitter, but Im going try to solve this on my own, and then, maybe a fitter, since the last time didnt go as planned, I will post updates, thx


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PostPosted: Sun Sep 16, 2012 10:51 pm 
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83cm inseam with 73.5cm height(c-bb to top of the saddle)


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PostPosted: Mon Sep 17, 2012 9:46 am 
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Joined: Fri Jul 27, 2012 8:34 am
Posts: 98
digitalnorbs wrote:
I'm beginning think that my hamstrings are the weakness here, I dropped my seat to 68.5 and my left foot is almost even with the right side as for the symmetry goes.
I'm will try 68 tomorrow, the big setback helps me with comfort for sure, never been this comfortable on a road saddle before.

gSent from my iPad using Tapatalk HD


Saddle setback can be deceptive. Unless you have checked with KOPS (as mentioned before) 8 cm seems extreme. Hinault/Genzling came up with the concept of pushing the rider farther back on the saddle, but this was done only when the rider had long enough femurs. A big setback will cause lots of problems if your anatomy doesn't support it. Also, if you are running lots of setback, your saddle is effectively higher than what you are measuring, if you measure straight up the post from the BB.


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PostPosted: Mon Sep 17, 2012 10:14 am 
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Joined: Wed Feb 09, 2005 4:51 am
Posts: 1725
Colonia wrote:
Also, if you are running lots of setback, your saddle is effectively higher than what you are measuring, if you measure straight up the post from the BB.


Which is also why after so many years of tweaking, found that measuring from BB center to effective location of sit bones is a more reliable measurement for me on different bikes due to the slight variances in angle, seatpost setback, saddle tilt, saddle sag etc, etc. That is of course with consideration of actual setback from BB center as saddle differences will affect your position too.


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PostPosted: Mon Sep 17, 2012 11:03 am 
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Joined: Tue Aug 14, 2012 7:36 am
Posts: 53
80 cm inseam, saddlehight 70 cm.

Recently I mounted a new saddle and found that it had raised the hight by 1 cm and that was to high. I will try to raise my saddle 2-3 mm at some point but I'm not to keen as my current hight has been good on some fairly long trips.


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Posted: Mon Sep 17, 2012 11:03 am 


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PostPosted: Tue Sep 18, 2012 7:52 pm 
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Joined: Mon Jul 31, 2006 6:49 pm
Posts: 438
friends, thank you for all your help so far, few days ago, I moved the saddle few cm forward and up, and that killed my hamstrings, so going up is no good for sure, then went back to the last position that I liked, then moved the saddle a bit more down, definitely better, went on a very hard ride with a friend whom is a very strong, and while spinning the postion was great, but when came to putting down the power, I had to shift forward on the seat all the way to the nose, so now I need to find a middle ground, and maybe this will be it=) more updates to come


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