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I found your spreadsheet when I was building up a new bike and I used the guidlines in the spreadsheet when ordering the frame and setting up the bike. I have now done 1000 km on the new bike, and the fit feels amazing! The only things I have changed from the data in the spreadsheet is to lower the seat 5-7 mm and move it 7-8 mm forward. The changes made based on my feeling on the bike.
Today I went to the LBS to have my fit checked according to their body-scanner. They were scratching their heads because they had never seen a bike set-up so well by someone not having access to some ''pro set-up tools''. According to their measurements my seat is 2,1 mm to high, and the seat is 1,5 mm to far back. Everything else within ''measurement errors''. You can actually say that the mentioned measurements for the seat is also within measurement errors, but I mention them here to indicate that the fit is spot on.
Thanks for the excellent spreatsheet. Without it I would have bougt a frame one size to big, ordered 172,5 mm crank arms instead of 175 mm and I would never had gotten such a nice fit without the guidlines
PS... I'm glad that I could participate (you now use a picture of my arm in the spreadsheet)
great spreadsheet ... it helps a lot
What reach of the bar you consider in your calculation? I'm using a compact bar with a reach of only 72mm, so I ended up with 10mm longer stem as proposed in your calculation.
05 Time VX Edge
03 Canyon MR8
Thanks for all your work. It's very interesting, and quite some distance from where I currently am. I am going to give this a go and move towards the suggestions. It seems my custom fit frame was made with a very slack seat angle, and probably for good reason (72.5 degrees I think), so I can't get very close to the seat to bottom bracket setback (Still +2cm), but then my femurs are very long. So it's all a matter of compromise. Whilst the changes will certainly enable me to move forward and down, which I think will be a good thing.
I'm in the process of getting a new race bike so it's time to try things out before I buy. I'm going for a fitting later this week so I now have another set for reference.
I am curious, is there a specific seat tube angle that is assumed? I broke out the trig and gave up trying to figure it out.
I am very interested in bike fit as I have recurring medial knee pain.
Clearly there are lots of factors affecting a good fit and lots of balancing of these factors in order to get the best fit for an individual.
My question is this: What are the overall biomechanical goals of the correct bike fit (for me this would mainly be in relation to comfort rather than performance)? Forget frame lengths, saddle setback and so on, what are we trying to acheive in terms biomechanics?
For example what are the kinematics and kinetics of the lower limbs that are desired and where do these values come from? References? A knee flexion angle of 150-155 degress has been mentioned here for example, but how about internal/ external rotation of the knee, ankle and hip motion, joint moments within the hip, knee and ankle etc...
I realise accurate kinetics and kinematics can not be checked by eye but that is the benefit of have access to skin marker based motion analysis and fluroscopy amongst other little goodies
Link is working
If you take your measure correctly you will find that in most of the cases that measure is identical than your inseam perhaps one or two cm. up or down. Once you have torso length m. you need a complicate calculation, with angles, sine and cosine in order to find the perfect angle for your torso. And you must install some other excel trigonometric module and...you know it´s more difficult than v8 datasheet for any language.
From the practical point of view, this formula could be simplificated as this
(Put this measure as you inseam in datasheet)
Virtual Inseam Length = ((102/100)*(Real Inseam length-((Torso length-Real Inseam Length))/2))
Is not exactly because is not trigonometric, but works. And perhaps must be included, in order to obtain more accurate results, nevertheless i´m pretty satisfied with v8 because is as easy as it can be and give very good results. Sometimes "perfect" and "very good" are big enemies . Greetings and thx for your feedback.
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