Originally Posted by
Bob Ross
fwiw framebuilder Dave Kirk advocates a similar approach. Copied/pasted from a ~10 year old post Dave made on another cycling forum:
"Let me first say that if you are a strong devotee of the KOPS deal then you will strongly disagree with what I'm about to share. I personally think that KOPS is as valid as standing over the top tube and seeing how much room between your crotch and the top tube. All one needs to do is look at the two fastest type of bikes out there - the new school time trial bike (knee way in front of the spindle) and a recumbent (knee more than a bit behind the spindle) to realize that this knee-pedal thing is crap.
That said here is a way to get your ballpark fore/aft saddle position. Note I'm not talking about reach from saddle to bars. Saddle to bar reach is a separate deal and should not be adjusted by moving the saddle fore/aft. Reach is a function of toptube/stem length.
1) put your bike in a medium easyish gear and ride up a very gentle grade. I use a 42-17 up a slight grade where I can maintain my natural cadence of 85ish without great effort.
2) put your hands on the tops of the bar next to the stem and ride relaxed like this for a bit. Let your body fall into a natural arch and relax.
3) now, with your body relaxed, lift your hands from the bars WITHOUT sitting up or changing the angle of your hips and lower back. Lift just the hands off the bars. Just and inch or so. Do not sit up.
3a) if you can do this without strain or by using a great deal of core strength then your fore/aft saddle position probably isn't bad and is in the ballpark.
3b) if you have a hard time doing this even after a few tries then it's a pretty good bet that your fore/aft deal could use adjustment. If you tend to fall forward when your hands are lifted it's a good bet your saddle could go back. If you tend to fall back then your saddle is way too far back. The latter is pretty rare.
This test, like all tests is not absolute or perfect but I've found it to be a good general rule. I think more folks will find themselves falling forward (instead of backward) and need to move the saddle back. Most folks that have had a fitting that is built around KOPS will have a saddle that is too far forward and will put too much pressure on their hands (I'm still not talking about reach here). This will make folks want to fit shorter stems and to raise the bars. This will have the double negative whammy of making the bike handle like **** and make you want an even shorter-higher stem.
By having the feet the right distance in front of your hips your ass and lower back muscles (the best ones you got!) can easily hold your position. You can try this right now in your chair while you should be getting some work done - sitting in your chair put your heels 6" in front of the chair on the floor. Lean forward a bit. Easy as **** eh? Now move your feet back so the balls of your feet are under the leading edge of the seat and lean forward a bit. It's takes much more core strength to hold this unnatural position. It's the same basic deal on the bike. Your feet support you and the added weight on your feet can be put into the pedals. If you pedaled with your hands then having a lot of weight on them would kick ass.
Give it a try. If you descide to make changes make them very small and a little at a time. A little can go a long way."
Hard to apply a rule that doesn't specify an actual grade. Small angle differences make the feel of set back very different, as each degree of slope effectively moves the saddle back a cm.
I love Dave Kirk, but he is essentially attacking those (Pruit) who think gravity is providing some sort of power advantage. KOPS was just a rule of thumb that was easy to measure to get reasonable set back for some groups of people, not a formula for peak power. It isn't a bad starting place for many people - but some folks have different enough proportions that it fails in its intent.