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

Seat Tube Confusion

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.

Seat Tube Confusion

Old 03-25-21, 03:29 PM
  #1  
brandon_lafave
Newbie
Thread Starter
 
Join Date: Mar 2021
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Seat Tube Confusion

I'm embarking on designing my first frame and ordering the tubes and such and I'm having a hard time understanding when/if a seat tube collar is needed. I'm trying to find the right seat tube to buy and just a bit confused. I'm building a SS Mtb and the BikeCad model I'm going off of has a bent ST which has been hard to find. I found one on frame builder supply but it's external butted which I don't know if I need a seat tube collar with it. I'm diving straight in but need to learn a lot!
brandon_lafave is offline  
Old 03-25-21, 03:39 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 15,169

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3011 Post(s)
Liked 1,336 Times in 934 Posts
More specific info needed. Steel or other material? Is SS mtB a single speed or a Stainless Steel reference? How about the found ST dimensional specs? Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-25-21, 04:05 PM
  #3  
brandon_lafave
Newbie
Thread Starter
 
Join Date: Mar 2021
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Andrew R Stewart View Post
More specific info needed. Steel or other material? Is SS mtB a single speed or a Stainless Steel reference? How about the found ST dimensional specs? Andy
Thanks Andy! Steel single speed mtb. The ST length is 450mm
brandon_lafave is offline  
Old 03-25-21, 04:30 PM
  #4  
guy153
Senior Member
 
Join Date: Dec 2019
Posts: 606
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked 123 Times in 101 Posts
If it's external butted you can just TIG weld right onto that. That's basically why they do that. Obviously make sure you cut any extra tube you don't need off the bottom so you're keeping the fat bit that you need

Then you can just leave a bit of ST sticking up above the TT and stays so you can cut a slot and either just buy a collar to clamp the seat-post or weld on some kind of a pinch-bolt. I leave 48mm of extension which works well but you probably don't need that much.
guy153 is offline  
Old 03-25-21, 04:57 PM
  #5  
brandon_lafave
Newbie
Thread Starter
 
Join Date: Mar 2021
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by guy153 View Post
If it's external butted you can just TIG weld right onto that. That's basically why they do that. Obviously make sure you cut any extra tube you don't need off the bottom so you're keeping the fat bit that you need

Then you can just leave a bit of ST sticking up above the TT and stays so you can cut a slot and either just buy a collar to clamp the seat-post or weld on some kind of a pinch-bolt. I leave 48mm of extension which works well but you probably don't need that much.
This is great. Thank you!
brandon_lafave 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 - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.