Jackal's Bike Fit Methodology

My conclusion after scouring the net over this topic; its very subjective and there are just too many theories out there. However, it is important to note that while the subject is chaotic in its variety of approaches, there are methods to give one a good starting point AND that can be transplanted easily from one bike to another, be it an upgrade or just another ride.

To me it surely beats 'just to have a personal feel' of the bike, which i do not dispute is the best approach since its suited to the user. However, I do not subscribe to the idea of just using 'the force' every time i set up my bike for varied missions or when i get a new frame or something. I need a logical system (that I can understand and believe in) whereby I am able to set-up more or less for an 'optimal' ride on that particular frame, tweak it by feel over many rides and then put all these into meaningful records that can be re-used or just as future reference.

Herewith, my own bike fit procedure and measurements, based on a few principles in correct order when doing your bike acquisition and followed by fitting :-

1. The frame must be correct, so that no extreme changes is required on seat post, stem, seat, crank length - Based on Dave Moulton : Frame Size = Height / 3.3. For me this is 181/3.3 = 54.85cm....plenty close to the 55.5cm Master Piu (c-c measurement). This is only true for straight top tubes. Sloping top tubes require a different method but same principle, look up Dave's blog.
   
2. Crank length is important but not that important at the same time. It depends more on what kind of riding one plans to do. Mashers will want longer cranks and spinners will want shorter cranks for smoother spinning motion. Having said that, depending on your femur length, you should never choose a crank length that is too long or too short - I'm using 172.5mm now but was on 170mm. Though the difference is small, I can feel that my cadence is not as smooth and high as before. Its a matter of adaptation since the change is little. Peter White has a good take on this subject.
   
3. Saddle Height is determined as a collective total measurement between 106%-109% (increasing 'aggressiveness') of your inseam. This will give the length from the optimal sitting position at the top of the saddle, right down to the centre of the pedal axle - this is also something mentioned by Dave Moulton but most did not mention from which point of the saddle clearly. For me its only logical to have it from the point where you normally sit comfortably and optimally. This can mean that the line will not be parallel to the seat tube, like in my case I tend to sit a little bit backwards on this frame with the seat pushed back. EDIT : some sources seems to mention as well while 109% gives the ideal max power output, its more meant for shorter rides/sprints. For endurance and longer rides, something between 106-107% will be more ideal.
   
4. Knee over spindle is not law but a good starting point for a Neutral Fit (a lot of people are skeptical but this IS the method used by even the pro fitters and sports institutes, surely this is saying quite a lot about KOPS), for this, move the saddle fore-aft to meet KOPs, bearing in mind that the saddle height will be affected (do the saddle to pedal adjustment again with the new fore-aft position) - since I am doing my own fitting this plumb bob method is quite hard for me to judge from the top of my seat...so I find that an even better way is to make a mark on your top tube where the vertical line intersects with the pedal axle center when the crank is at the 3 and 9 o'clock position. I'm lucky, this coincides right at the 'T' in the MASTER PIU wording on the top tube. With this I can always monitor while I am riding and feel the differences and preferences as I ride more.
5. KOPS will provide a neutral fit based on your optimal sitting position. However, to compromise with climbing, sprinting and normal riding position, your KOPS changes - and this makes sense based on the article by Keith Bontrager...you'd ideally want your CG (centre of gravity) over the spindle axle for the most optimal AND comfortable position in the 3 riding positions. However, while it makes a hell lot of sense to me, I have no idea where my CG is!! I believe no layman know either. That being said, I think its something worth keeping in mind as part of the 'feel' while cycling. The CG theory makes sense with Peter White's article as well where he focus on balance on the bike when the body is at an angle but this was focusing on stem reach. CG, I suspect is the road towards the unified theory of bike fitting!
6. Once Saddle Height and Fore-Aft is done. Its time to do the REACH and Saddle-Handlebar Drop. This can be achieved by changing the stem length and height - Dave Moulton has a nice guideline for this and I'm pretty close to his recommendation. Do note that with higher stem height, the reach is also effectively shortened but the posture will be theoretically, more comfortable for most. I tend to go for a slightly more aggressive drop about 9cm and I like the long reach feel where I can easily stand and change my CG depending on the terrain. Peter White has a good method for this as well; the reach should be the further point whereby the rider can remove his arms and can still balance in that angled position. The arms should feel little pressure or not pressure in supporting the body weight.
   
7. Cleats - most important this to have the centre marker of the cleat right below the ball of your foot. The centre of the cleat body should also be right below the ball of your foot. Cleat angle is more tricky because different people tend to have inward pointing or outward pointing feet. Or worse still each foot has asymmetrical natural properties! Do this....walk normally a few steps and stop...look at your feet and see the orientation/angle. That's how it should look like on the pedal as well.

Some of us may have high tolerance for discomfort, some don't. It is best that as a cyclist, at least for me, to know the most comfortable position on the road bike. Any discomfort right now is likely to be a potential cause of future injury with prolonged riding. Also from this point, I can gauge how aggressive I can setup my bike for different rides (short hard fast or slow long ride). Best still, maybe I can get good bike fitting and consider this as a part time job!


I also do my best to note down the following measurements using this picture as a guide. This will be the standard Master Piu measurement that does not change.


The next picture below details the things that I can change to fit optimally to my needs and I take these measurements down too, to the best of my ability (with a meagre measuring tape only!)


This WILL help as my own personal fitting record and it WILL be useful for future references. With every change I note down; what is changed, when, why I changed it and by how much.


Source(s) :-
- Dave Moulton - a well respected and retired UK frame builder in the US (http://davesbikeblog.squarespace.com/blog/category/bike-fit)
- Peter White - legendary wheel builder in the US (http://www.peterwhitecycles.com/fitting.htm)
- Sheldon Brown - god bless his soul. The bike guru who has done so much for the cycling community over the internet! (http://www.sheldonbrown.com/)
- Keith Bontrager - yup, you'd prob see his name on parts and lance's new wheels (http://www.sheldonbrown.com/kops.html)
- Bikeforums.net
- Various YouTube videos, cycling websites, etc