Originally Posted by
Fat Boy
I have a bad wing, so Ive been on my rollers with a fork stand. It's Fredilicious, but better than no riding. Anyway....
With the fork held solid the frame flexes under you as you pedal, as we all know. The deflection appears to be primarily in the front triangle. As the frame flexes, it tilts the rear wheel slightly side to side. As this happens, the rear steers about an inch or 2 side to side. So when riding normally down the road this must be happening to some extent, which would contribute to tire scrub.
I've always said that frame stiffness doesn't affect efficiency. I'll still say that the frame itself is not 'absorbing' (I don't know what that means, honestly) power. I will say that this deflection may very well effect tire scrub which would affect overall efficiency.
Any thoughts?
When you're riding rollers, the fork is held tight and you get flex in the frame. But then you compare this to "riding normally down the road" where the fork is not held tight. You say the flex must be happening "to some extent" and I agree, but no where near the extent if the fork was held rigidly (which it isn't). So there must be some flex in the fork, and some in the frame. I guess there would also be some flex in the handlebars, and even some in the wheels. I dont think you can draw too many conclusions about flex during a normal ride on the road, compared to a rigidly held fork on a roller.