Knee position above pedal and seat setback

[Aston]

Help needed I'm a recreational bicycle user, rather than a sporty dashing up hills cyclist, just shortish slow trips on an old Thorn Club Tour, maybe 20-30 miles at a time.

I've realised that my knee position above the pedal is not 'optimal' from everything I've read, dropping a plumb line from my knee cap shows that my seat position should be another 20mm back. Is this a big deal? If I change the seatpost for an additional 20mm setback will I notice a big difference or not for the sort of cycling I'm doing?

I've a Brooks B17 which limits the about of room I have for adjusting the saddle position.

Advice appreciated, thanks

 

[fossyant]

Are you sure your saddle is the right height, if it's too low, your knees will be further forward. Rule of thumb is the plumb line should be roughly at the axel. Can you tap the saddle a little further back on the rails.

 

[Webbo2]

Help needed I'm a recreational bicycle user, rather than a sporty dashing up hills cyclist, just shortish slow trips on an old Thorn Club Tour, maybe 20-30 miles at a time.

I've realised that my knee position above the pedal is not 'optimal' from everything I've read, dropping a plumb line from my knee cap shows that my seat position should be another 20mm back. Is this a big deal? If I change the seatpost for an additional 20mm setback will I notice a big difference or not for the sort of cycling I'm doing?

I've a Brooks B17 which limits the about of room I have for adjusting the saddle position.

Advice appreciated, thanks

Apparently the plumb line thing isn’t necessarily a thing any more especially when lots of bike fitters suggest fitting your cleats as far back as they will go.
Are you having issues with your current position if not why change.

 

[Aston]

Are you sure your saddle is the right height, if it's too low, your knees will be further forward. Rule of thumb is the plumb line should be roughly at the axel. Can you tap the saddle a little further back on the rails.

No the saddle won't move any further back, it's as far as I can get it to go, the plumb line drops about 2cm in front of the axel. I've not been cycling long, so it's all new to me!

 

[Aston]

Apparently the plumb line thing isn’t necessarily a thing any more especially when lots of bike fitters suggest fitting your cleats as far back as they will go.
Are you having issues with your current position if not why change.

No cleats, not having any issues, but TBH, I've only cycled maybe 200 miles on it so far. I'm maybe just obsessing a bit!

 

[HLaB]

Its (KOPS) a myth I think, plenty of sources say it is these are just some of them:

https://www.sheldonbrown.com/kops.html


View: https://youtu.be/dRo5vmJWWhw?si=rQNTwFzjD0gIV2Wq



View: https://youtu.be/rmB9jUTX-XM?si=sCtIqayyANwtzkWS

 

[fossyant]

The Badger says it should be around the axel as a starting point, and you get the formula for saddle height. My bikes are all set up according to his book - Racing and Training Techniques. (I am old though).

 

[Drago]

To answer your question...

It's not a big deal.

If its comfortable and not causing injury, youre fine. No point being in the most surgically efficient position if its not as comfortable as a slightly different set up. Pro racers will settle for discomfort, within reason, where required in the pursuit of maximum performance but us normal Joe's and Jane's don't have to. Use it as a starting point rather than a blueprint.

 

[cyberknight]

Following this thread as my synapse i cant get the saddle far enough back to get my preferred fit as im 1 cm to far forward with the current seatpost at its max as the upper clamp design doesnt allow the saddle any further back . 25 .4 cm post .

 

[Ming the Merciless]

What is the layback on your seat post?

 

[rogerzilla]

Most frames these days have a 73° seat angle, which doesn't really work with significant setback and Brooks saddles unless you seek out a seatpost with enormous layback. There aren't many aluminium posts with layback over 30mm, as it puts a lot of stress on the post; the Nitto/Rivendell steel lugged post does over 40mm, and the odd carbon one does too.

KOPS may be a myth but, if you find yourself shuffling backwards when pedalling, your seat is too far forwards, and vice-versa.

I'm probably at the outer limits of saddle position, as my most comfortable bike has saddle setback of 95mm, only possible as it's an old frame with a 71° seat angle. If we take "inseam" as trouser size, my saddle height is 0.945 of it. The centre of my cleats is pretty much in line with the widest part of my (large-ish) foot.

To get seat height, it's hard to beat this rule of thumb: with cycling shoes on, your knee should just be locked out, without stretching to reach, when your HEEL is on the pedal.

 

[mickle]

If 'plumbline through pedal axle' was a thing we wouldn't have recumbents. Or modern geometry mountain bikes.

 

[cyberknight]

If 'plumbline through pedal axle' was a thing we wouldn't have recumbents. Or modern geometry mountain bikes.

indeed , steve hogg has thoughts on kops and he basically dismisses it instead he goes for point of balance . I know the 4 cm setback from BB works for me and 3 cm is too far forward .