Go Back  Bike Forums > Bike Forums > Framebuilders
Reload this Page >

Custom seat post

Notices
Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

Custom seat post

Old 07-10-22, 08:01 AM
  #1  
hevysrf
Junior Member
Thread Starter
 
Join Date: Sep 2004
Posts: 130
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 66 Times in 31 Posts
Custom seat post

Anyone willing to do some custom work? Looking for 4" setback, 6" rise, steel?
hevysrf is offline  
Old 07-10-22, 06:43 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,998

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4171 Post(s)
Liked 3,789 Times in 2,269 Posts
What diameter?

The first thing I think of is a post with a close to horizontal extension of 7/8. A common/cheap steel seat clamp could then be used. This is much like what bikes had nearly 100 years ago. But back then the post's 7/8" extension ran forward to offset the really relaxed ST angles used back then.

If the ST ID fit diameter is a common 4130 tube size the cost to make will be fairly low. So What diameter? Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 07-11-22, 09:34 AM
  #3  
hevysrf
Junior Member
Thread Starter
 
Join Date: Sep 2004
Posts: 130
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 66 Times in 31 Posts
Thanks for replying Andy, 25.6. I'm using one of these but along with the Rube Goldberg seat clamp I fabbed , its slowly bending.





This setback on a cruiser frame is comfortable for me but maybe I should look at a pedal forward frame instead. any feedback on this rans?
hevysrf is offline  
Old 07-11-22, 09:55 AM
  #4  
79pmooney
Senior Member
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,825

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 128 Post(s)
Tagged: 0 Thread(s)
Quoted: 4741 Post(s)
Liked 3,860 Times in 2,509 Posts
TiCycles could certainly make such a post. They aren't cheap. But unusual designs is something they regularly take on and do well. (In-house engineering and machining skills that go well beyond frame building.)

I have two posts with 60mm setback from them. A machined bar of aluminum that the tube is fitted into. Machined to accept the excellent Thompson clamp parts. They regularly use aluminum for the post or titanium if you want to pay the premium. I don't see why they couldn't do steel. Sounds like your post would be a full step beyond mine and require a new approach. Exactly what TiCycles thrives on. But the post might cost more than the rest of your bike.
79pmooney is offline  
Old 07-11-22, 10:14 AM
  #5  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,362
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,662 Times in 2,496 Posts
That seatpost looks like it was made for a vintage seat clamp. Some bike shops might have one.

As far as the rans goes, I think people generally like them, if they can stand the position. There are other pedal forward bikes. Rans sued Trek because Trek was making one. I think they lost. In any event, Trek still sells the Electra townie, which is pedal-forward.

Last edited by unterhausen; 07-11-22 at 10:19 AM.
unterhausen is offline  
Old 07-11-22, 09:10 PM
  #6  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,998

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4171 Post(s)
Liked 3,789 Times in 2,269 Posts
The imaged post with the bracing strut looks to be a mid 1980s BMX one. I don't ever remember seeing one of them min a 25.6 diameter though. Given the large amount of set back I would want a pretty thick wall to reduce the bending. Before I would consider making a seat post I would want to have the frame on hand to both self measure the ST ID and to use as a go/no go gage for the new post. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 07-12-22, 06:18 PM
  #7  
hevysrf
Junior Member
Thread Starter
 
Join Date: Sep 2004
Posts: 130
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 66 Times in 31 Posts
The current strut is a 25.6 eBay special, its quite thick but soft enough to be slowly bending, might be able to see it in the photo. The bike is an electra, mid-90's Klunker style. Right now it's comfortable for the amount of mileage I'm able to achieve.

Looking at the seat tube, it's incredibly thin walled compared to the seat post. I imagine it would deform if the post was stiffer.


I have trouble riding head down and putting weight on wrists and shoulders but like to able extend legs and straighten my knees on the pedal downstroke. Might be a better idea to try a Townie or a Loft designed for upright posture.




hevysrf is offline  
Old 07-13-22, 08:13 AM
  #8  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,998

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4171 Post(s)
Liked 3,789 Times in 2,269 Posts
"but like to able extend legs and straighten my knees on the pedal downstroke." hevysrf

Well, I'm good with what works for you. However, the usual seat height results in around a 20-30 degree of bend between the femur and the tibia when "fully" extended. I find that more height than this is often preferred by those that have a rather slow cadence, for all the better and worse that this brings with it. If riding by one's self this is a moot point. If riding with others the ability to quicken the pace briefly can be essential to whether you'll be able to be close enough to talk with your fellow cyclists, and a slow cadence generally makes for a slow speed up from stops and such. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 07-15-22, 07:39 PM
  #9  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,362
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,662 Times in 2,496 Posts
It sounds like you are a good candidate for a 'bent.
unterhausen is offline  
Likes For unterhausen:
Old 07-17-22, 06:27 AM
  #10  
hevysrf
Junior Member
Thread Starter
 
Join Date: Sep 2004
Posts: 130
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Liked 66 Times in 31 Posts
I did have a Tailwind for a few years, wasn't very inspiring. I occasionally look for a SWB bent, but they are pretty rare in the used market.
hevysrf is offline  

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.