Lay Back Seat Post

Lucozade1973

Can some one tell the benefits of a lay back seat post (Think thats what they are called) are?
When one is prefferable to a standard straight one?
I assume it is to help transfer weight back slightly and adjust the ride position lower....

benpinnick

Mainly it pushes the weight back over the rr tyre, and more importantly gives more length from bars to saddle.

Lucozade1973

Thanks for the reply, what are the benefits of this ride postion then?

andrewjoseph

The designed purpose of saddle rails, layback and straight seat posts, is to make sure you achieve the desired knee position over the pedal.

Using these adjustments to 'get your weight back', may result in poor bike fit and possibly injury.

If you use a layback post to put your weight back, you may need a shorter stem, as your reach will now be different, this will impinge on steering, making it faster and possibly 'twitchy'.

Lucozade1973

Ah, i see, i never heard of this knee over pedal bit, i do get pains in my knees after a time, i have a straight post but have never moved the saddle along the rails.
How do you know where the saddle should be for correct knee over pedal??

(Sorry for sounding thick, but i never heard of this. :oops: )

andrewjoseph

There are several sites that give this info,(search for KOPS: knee over pedal) but the way i do is as follows:

get the saddle height correct first (within a cm or so), so you have a slight bend in the knee at the bottom of the pedal stroke and you are not rocking your hips to maintain contact with the pedal, (you may need someone to help you or use a turbo trainer).

ensure you have your feet/shoes in a good position for riding, pedal axle underneath joint of big toe, if you use cleats, make sure they are set comfortable for you.

Sitting on the bike, feet on pedals at 3 and 9 o'clock (horizontal), a weight on a string should pass from the area on the inside of the knee beside the knee cap, down through the middle of the pedal axle.

Adjusting this will be a function of foot position, saddle height and saddle setback. i.e. changing foot/cleat position will alter things.

Adjusting height of saddle will affect knee position as the seat tube is not vertical.

Move the saddle on its rails forward or back to suit, also check the saddle angle, tilted too far nose up can cause discomfort in the perineum, too far nose down and you are sliding forward and putting too much pressure on your wrists.

If you can't get the saddle back far enough on the rails to get your knees in a good position, then you may need a layback seat post, or a saddle with longer rails.

The main thing is to get comfortable, power may be traded for comfort if you are racing but only for a short time.

These are guidelines only, to get you in the area, you make the final decision on what you need/want.

if you are having knee pains it may be that the saddle height is wrong, raise or lower depending on where the knee pain is.

I know that i have to have my saddle about 91 cm above the pedal on both my bikes, even though the cranks are different lengths.

Lucozade1973

Andrew,

This is brilliant info, i will have a go tonight and play around from there.

Thanks again for your time and detailed guidelines.

andrewjoseph

hope I have helped.