Builder's Spotlight The Paceline Forum Builder's Spotlight


Go Back   The Paceline Forum > Bike Fit

Reply
 
Thread Tools Display Modes
  #16  
Old 11-03-2017, 09:49 AM
OtayBW OtayBW is offline
Senior Member
 
Join Date: Feb 2008
Location: NoBaltoCo
Posts: 3,516
Quote:
Originally Posted by Kontact View Post
I don't know why you'd use a zero set back seatpost with a road bike. Road bikes are normally designed for a standard setback seatpost (25mm or so). If you wanted to build a custom frame to use a zero set back, you would relax the seat post angle by 2.5°, so you'd need a 71.5° seat tube angle.
Some people have short femurs and need either a steeper STA with a conventional (setback) post, or a zero setback post on a 'stock' frame to accommodate their weight distribution properly....
__________________
The older I get, the faster I was...
Reply With Quote
  #17  
Old 11-03-2017, 12:46 PM
Kontact Kontact is online now
Senior Member
 
Join Date: Apr 2011
Location: Sunny Seattle
Posts: 1,669
Quote:
Originally Posted by OtayBW View Post
Some people have short femurs and need either a steeper STA with a conventional (setback) post, or a zero setback post on a 'stock' frame to accommodate their weight distribution properly....
Some people, but not false_Aest who couldn't get his seat in a good position because of it. The vast majority of people aren't going to get a good fit with road geometry and a zero seatpost.
__________________
Get off your junk: www.kontactbike.com
Reply With Quote
  #18  
Old 11-03-2017, 01:42 PM
macaroon macaroon is offline
Senior Member
 
Join Date: May 2013
Location: United Kingdom
Posts: 644
Quote:
Originally Posted by OtayBW View Post
Some people have short femurs and need either a steeper STA with a conventional (setback) post, or a zero setback post on a 'stock' frame to accommodate their weight distribution properly....
Saddle position fore/aft has literally nothing to do with the length of your femurs. It's been covered multiple multiple times on this forum alone. I don't know why people carry on with this idea.
Reply With Quote
  #19  
Old 11-03-2017, 01:46 PM
macaroon macaroon is offline
Senior Member
 
Join Date: May 2013
Location: United Kingdom
Posts: 644
Quote:
Originally Posted by Kontact View Post
I don't know why you'd use a zero set back seatpost with a road bike. Road bikes are normally designed for a standard setback seatpost (25mm or so). If you wanted to build a custom frame to use a zero set back, you would relax the seat post angle by 2.5°, so you'd need a 71.5° seat tube angle. So when you use a zero setback with a 74° small bike seat tube angle you are automatically going to have to clamp the seat 3.5cm further forward of optimal. That's not only ugly, it destroys saddles.

I'm surprised Ben was okay with that.
If you have long legs and like to run alot of saddle to bar drop then an inline post would probably be required. Just speaking from experience. On my bike with less drop, I use a 25mm setback post.
Reply With Quote
  #20  
Old 11-03-2017, 01:48 PM
OtayBW OtayBW is offline
Senior Member
 
Join Date: Feb 2008
Location: NoBaltoCo
Posts: 3,516
Quote:
Originally Posted by macaroon View Post
Saddle position fore/aft has literally nothing to do with the length of your femurs. It's been covered multiple multiple times on this forum alone. I don't know why people carry on with this idea.
Perhaps because not everybody shares your opinion....

Sent from my SM-G935V using Tapatalk
__________________
The older I get, the faster I was...
Reply With Quote
  #21  
Old 11-03-2017, 01:52 PM
Kontact Kontact is online now
Senior Member
 
Join Date: Apr 2011
Location: Sunny Seattle
Posts: 1,669
Quote:
Originally Posted by macaroon View Post
If you have long legs and like to run alot of saddle to bar drop then an inline post would probably be required. Just speaking from experience. On my bike with less drop, I use a 25mm setback post.
There is no reason to sit too far forward on a road bike. Including for low bars.

Quote:
Perhaps because not everybody shares your opinion....
As far as long femurs go, try plotting it out sometime in a KOPS diagram. Use the same leg length and change the femur length and shin length, shortening one and adding to the other. The amount of actual change due to femur length is tiny.

That isn't opinion, just basic geometry.
__________________
Get off your junk: www.kontactbike.com
Reply With Quote
  #22  
Old 11-03-2017, 02:46 PM
macaroon macaroon is offline
Senior Member
 
Join Date: May 2013
Location: United Kingdom
Posts: 644
Quote:
Originally Posted by Kontact View Post
There is no reason to sit too far forward on a road bike. Including for low bars.


I don't know how he's managed 19 consecutive grand tours with that inline seatpost....

Reply With Quote
  #23  
Old 12-06-2017, 05:59 PM
sparky33's Avatar
sparky33 sparky33 is offline
Senior Member
 
Join Date: Feb 2013
Location: Wellesley, MA
Posts: 1,947
Quote:
Originally Posted by fa63 View Post
I like it. It's a good way to compare.

fwiw anyone else find it odd or maybe clever that Moots measures stack & reach including the headset top, instead of at the top of the headtube as is common? I couldn't reconcile their figures without their reading the geometry footnotes.
__________________
Steve Park
Reply With Quote
  #24  
Old 12-06-2017, 09:02 PM
Kontact Kontact is online now
Senior Member
 
Join Date: Apr 2011
Location: Sunny Seattle
Posts: 1,669
Quote:
Originally Posted by macaroon View Post


I don't know how he's managed 19 consecutive grand tours with that inline seatpost....

What does that mean? Lot's of folks ride great in uncomfortable positions. Look at Sean Kelly and his way-too-low saddle. But that isn't the way road bikes are designed to be ridden. That's a triathlon position.
__________________
Get off your junk: www.kontactbike.com
Reply With Quote
  #25  
Old 12-06-2017, 09:05 PM
Kontact Kontact is online now
Senior Member
 
Join Date: Apr 2011
Location: Sunny Seattle
Posts: 1,669
Quote:
Originally Posted by sparky33 View Post
I like it. It's a good way to compare.

fwiw anyone else find it odd or maybe clever that Moots measures stack & reach including the headset top, instead of at the top of the headtube as is common? I couldn't reconcile their figures without their reading the geometry footnotes.
Given the amount of headset that sticks out of different types of head tubes, measuring top or bottom is arbitrary. Does a bike with an external headset truly have the same stack as one with an inset headset? Try slamming the bars on both and the answer is "no".

Yet another reason stack and reach are limited by their weirdness.
__________________
Get off your junk: www.kontactbike.com
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:06 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.