Being old(ok, over 45), I was taught, for bike fit, to have your legs virtually all the way extended on the downstroke.
Watching the tour breakaway yesterday, both riders did not extend their legs at all, in fact I doubt there was more than a 120 degree angle between top and bottom halves of the leg (at the back).

Is this a ‘new way’?
Or have I always been wrong?
Ta
Alan.

IIRC the “ideal” starting position to start tinkering from is around 145 degrees, as it is usually measured and described by bike fitters (or 35 degrees knee flexion as biomechanists would usually describe it 😉 ).

There is more to fitting than just isolated numbers but I suspect what you are observing is a product of 3 things…

One is that the “adjust the saddle height so you knee is nearly fully extended” is misleading because doing this statically feels like the knee is nearly fully extended whereas in reality, when pedaling, the ankle plantar flexes more which in turn leads to greater knee flexion. So the “fitting by an extended knee” actually creates more knee flexion than you think dynamically.

The second issue is that a lot of amateur riders set their saddle much too far forwards. The increased hip angle at the lowest point of the stroke with the pros gives an illusion of a more flexed knee as their femur is more horizontal.

Third is that watching a video of a pedal stroke is itself quite misleading and you process what you see as a pretty flexed knee. If you were to watch it frame by frame then you will see a very short period of time where the knee is actually flexed to its maximum but easily missed by eye watching in real-time.

I guess a fourth thing is that there isn’t one uniform bike fot for everyone and there is a lot of variation between riders, even the pros. Not all pros have “optimal” fits and are pretty resistant to change too!

Thanks for that explanation – it clearly shows why I was never an Elite rider!
Thanks.

Saddle height is a hugely complicated subject, which I touched on here: http://www.oneclick.fit2ride.cc/?p=98
In summary, it has to be set using dynamic rather than static measurement and is hugely reliant on individual physiology.
Remember, there are no ‘rules’!

Things like aero also come into play, where a lower saddle position is usually more efficient. Also with things like power meters you can easily see the difference that changing saddle height makes to your ability to generate power, so there is more experimentation. Trend in TTing is towards lower saddle positions (proven aero and power advantages) and it makes a lot of sense to have your road bike position as similar as possible to your TT bike position to minimise the required adaptations.

Saddle height is a hugely complicated subject, which I touched on here: http://www.oneclick.fit2ride.cc/?p=98

That link is not working for me, perhaps this one:- http://www.fit2ride.cc/2014/06/09/first-rule-of-saddle-height/

Thanks, Fubar. Much appreciated.

Anyway, isn’t that ‘rule’ that you should have your heel on the pedal anyway with the leg extended, not the ball of the foot for which it wouldn’t be fully extended.

If you unclip one foot and use only the other to pedal with you can quickly see/feel the effect of different saddle heights and also sliding the saddle forwards and backwards on the rails.

In some positions it is difficult to avoid that ‘bobbing up and down’ effect whereas in more correct positions you can easily ‘pedal in circles’ with the one leg.

General rule of thumb, heel on pedal at the bottom of the stroke- in line with seat tube. The trouble when fitting is that different people have different flexibility, if you can get your flat hands on the floor (past touching toes) then you can ride with an almost straight leg, maybe 5 degree bend, but that’s assuming a level foot position throughout the stroke, not heel up at the bottom of the stroke.

As long as you aint rocking your pelvis or straining behind the knee you are generally good to go.

Getting people to pedal at 120 rpm usually shows you what’s good and what isn’t.