leonidnk
Karlstad, Sweden
Hi,
For test purpose I entered Shoe size as 44, A as 1810 mm, C as 840 mm and got a very strange very short frame:
What I did wrong?
Bicycle Design Software
Test of Fit Adviser
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Test of Fit Adviser
Have a look at my response to a similar question here: bikecad.ca/comment/663#comment-663. If you have further questions or comments, please let me know.
Test of Fit Adviser
Thank you for the answer.
I understand what you mean. However, I cannot understand, why the Fit Adviser cannot generate statistically valid frame geometry from incomplete input data. I really do not like at the begining go in customize the Fit Advisor.
In my case I believe, the seat tube is too long and top tube is too short.
Fit advisor results
When you say that the seat tube is too long, are you referring to the center to center measurement or the center to top measurement? Be aware that by default, the Fit advisor calculates a recommended center to center length. Notice that in the model you used for this test, the seat tube extends quite far above the top tube. This is going to result in a long center to top seat tube length for a given center to center seat tube length. If you are in fact referring to the center to center measurement, I assure you that there are many credible fitters out there that would adamantly believe the seat tube should be longer.
As for the top tube, the Fit advisor can be configured to calculate recommended values for top tube length. However, it doesn't do that by default. Instead, it calculates a recommended value for rider compartment. The top tube will adjust to suit the recommended value for rider compartment. Ultimately, the length of the top tube will also depend on the geometry of the selected stem and to a lesser extent the selected headset, spacers and other dimensions. When you say that the top tube is too short, do you also feel that the rider compartment is too short? If not, then the solution to obtaining your desired top tube length is to use a shorter stem.
I definitely wish the Fit advisor could, by default, satisfy every fitting philosophy. However, this is simply impossible. This is why I've made the Fit advisor so easy to customize.
Test of Fit Adviser
"I definitely wish the Fit advisor could, by default, satisfy every fitting philosophy. However, this is simply impossible. This is why I've made the Fit advisor so easy to customize" - I understand it. I perfectly got your point.
Hovewer, as a novice, I wish to have simple useful Fit Adviser. Fit Adviser based on generally accepted statistically valid frame geometry. Next, after some time of experience, I will consumize the Fit Adviser. But not now.
I know for sure, the actual Fit Advisor (FA) advise does not fit me:
And if we compair the advice with the chart below:
We can see very clear, how uncommon the FA advice.
Frame geometry charts
When I first saw your frame chart, I assumed it contained some sort of recommendations on what size frame would suit a given rider. However, it contains no such information. If it did, it would be easy to take that chart and customize the Fit advisor to match it. But in the absence of any fit recommendations, I assume the only point you are making with this chart is that the ratio of seat tube length to top tube length arrived at using the default settings in the Fit advisor are different than the ratios in your chart which appears to be the geometry chart for the Stradalli Trebisacce Red-Pro.
If I was meant to glean any further insights from this chart, I hope you will let me know.
Advise of Fit Adviser
I am sorry. Looks as I cannot bring my point forward. Probably, because my English is quite poor. I try again:
Any new MS Word users can choose some template (for instance "Invoice (Timeless design)) and start to use it. The template is not perfect for his need, but it works quite well anyway. When the user becomes more and more experience user, he makes the Invoice more and more stylish for his need.
With a frame geometry from Fit Adviser in my case, we can see completely opposite way. Very special geometry. Not a generally accepted geometry.
We can look around, if we need proof of the above:
http://www.halfords.com/wcsstore/libraries/document/road_bike_size_guide.pdf
http://www.ebay.com.au/gds/How-to-Choose-the-Correct-Size-Frame-for-a-Road-Bike-/10000000177578500/g.html
https://www.retul.com/frame-finder/stack-and-reach-tables/
Thus, my point: Please, give more usual frame geometry for any novice, who use your Fit Adviser first time. Because, customizing of Fit Adviser is a next and more advanced step.
Thank you in advance.