Backache

[Steed]

Sorry but you have lost me there. Does the NCX seat post convert up and down movement to forwards and backwards movement? Either way the change in geometry can't be good for one's knees. Unless, that is, one stops pedalling when bouncing?

 

[anotherkiwi]

It doesn't bounce, it absorbs the shocks, the pogo stick ones bounce. It does move slightly forwards but not enough to change your riding position. They really are the best invention since the bicycle IMO...

 

[Benjahmin]

They are a parallel arm mechanism that moves in an arc backwards/down as weight comes on and forwards/upwards to return. So, because of the arc, I think the relative distance from bum to peddle is pretyy much mantained. Your bum might be slightly loer but also slightly further back. The motion is a little discocerting at first but you soon get used to it.

 

[Danidl]

Sorry but you have lost me there. Does the NCX seat post convert up and down movement to forwards and backwards movement? Either way the change in geometry can't be good for one's knees. Unless, that is, one stops pedalling when bouncing?

Sorry I lost you.. what I was saying is that the knee has no problem with up down movement so if the saddle move up down so what! Normally we adjust the saddle so that the ball of the foot pushes down at near full extension on the pedal, at he bottom of the power stroke and the knee is nearly bent at the start of the stroke.
If the seat moves up and down a little so what... On average it's at the optimum point...
Side ways movement of the knee , however is very painful and expensive to repair as many footballers know to heir cost

 

[lee-wave]

Sorry but you have lost me there. Does the NCX seat post convert up and down movement to forwards and backwards movement? Either way the change in geometry can't be good for one's knees. Unless, that is, one stops pedalling when bouncing?

Actually it moves slightly backward and downward when going over bumps..but there is no real perception of this movement and the seat maintains it horizontal position ... I do not think it would cause any knee problems... but I have only one ride with it so dont really know...

 

[anotherkiwi]

Some of us have done thousands of km sitting on one, I think if it created knee problems you would be hearing about them.

 

[Georgew]

I think you meant reach the pedal with the ball of the foot only....but thanks to all for your help - I am going to have a rethink about saddles height etc...

No....I meant what I said. When seated on the saddle it should only be possible to touch the ground only with the ball of the foot rather than the whole foot. When coming to a halt, rather than remaining seated the rider should move forward straddling the cross-bar and having one foot remaining on the pedal ready to take off.
When seated with the correct saddle height and with the pedal crank in line with the seat-tube, the knee should have a slight bend. When pedaling the hips should not rock side to side as this means that the saddle is too high.

 

[Doomanic]

https://roadcyclinguk.com/how-to/technique/beginners-guide-how-to-set-your-saddle-height-on-a-road-bike.html#SxDEE2IJICkt8Ak1.97

 

[Gringo]

have considered the NCX seat post but dismissed the idea on the basis that when the seat post compresses (as it must do continually on uneven surfaces?) it will alter the saddle height relative to the pedals and potentially give rise to knee problems. Or am I missing something?

I have lots of knee problems and use the ncx without issue, the post movement is both down & backwards, even over bumpy ground you don't notice any shortening of ride height, if the going is rough enough to continually bottom out the seat post, you'll probably not still be pedalling Anywho.