ncscott

Hey all,
My seat has always been as far forward as the rails allow. My seatpost clamp however is set behind the post and I could get a more forward position if I replace the post with one that the clamp is directly on top the post. I notice that when pedalling hard I inch forward to the nose of the seat, so I know I like the forward position.
And now my question:
This winter I've experience knee pain. The seat position is the same its been for over 10 years (same bike, same seat). I suspect I'm suffereing from bursitis. What does a more forward position do to the health of you knees?
Scott

merlinextraligh

Most people do move to the nose of their seat pedaling fast on the flats, so that doesn't necessarily indicate that your seat is not far enough forward.

The starting point in this discussion is not where your seat is on the rails, but where your knee is in relation to the pedal spindle. Drop a plumbline from the bony putuberance at the bottom of your knee cap, and see where it is in relation to the pedal.

clutchy

with the pedal in what position? 3 o'clock?

fore0121

Yes, 3 o'clock.

merlinextraligh

yes, cranks parallel to the ground, pedal on the side you're measuring forward. Sorry I left that out.

trin2du

Have you changed pedals, shoes or cleats recently?

And rotating your setapost could let you move the saddle more forward, but it places more stress on the post than it was designed for and makes it more prone to failure.

curiouskid55

Very general generaliztion. If your knee hurts on the front seat is too far forward. If knee hurts in back seat is too far back. Seat position fore and aft is not only determined by the rails in the clamp but also seat tube height. Same seat for ten years? Surprised you dont have butt pain. Seat lasts me two years tops. If your seat has broken down it is functionally lower , so funtionally forward of original postion.

ncscott

I have done the plum line thing many years ago and since the bike hasn't changed, I cant imagine the plumline will change. With that being said, the plum line is a great reference for the average rider, but its intersting that tourists sit further back and time triailists sit further forward (as built into the angles of the frame). I'm curious what the effects of moving forward from the "plum line" is and if it might help with my knee pain. Its my understanding that a forward position uses more of the hamstrings and a rearward position used more of the quads, but have no clue how this affects knee pain.
Thanks,
scott

ncscott

Thanks Curiouskid. I'm not shure how the pain forward/back reference makes sence (it would seem to be oposite to me) but that was the info I was looking for. The seat recently did get changed (after the knee pain started) and am now confused how/why I sat on that thing for 10 years.
Scott

dsb137

The general rule of thumb is that if your knee hurts on the front, then the seat is too low (moving the seat forward has the net effect of lowering it...). If your knee hurts in the back, then your seat is too high (sliding the seat rearward has the net effect of raising it...).

Exactly what kind of pain are you experiencing? There are a lot of causes/cures for different knee pain...

curiouskid55

The short wheelbase geometry of a tt specific frame are for optimal aerodynamic rider position. It has nothing to do with comfort. Creeping forward on the saddle gets you more power over the top of your cranks at the expense of full leg extensiion and smooth power through the entire stroke. Of course world class TT riders can accomplish both but for mortals it should be considered bad form.