Seat tube sleeve
#1
Senior Member
Thread Starter
Seat tube sleeve
I putting the finishing touches on a new build and it will have a sleeve for the ST. The ST itself is 1.125.
For a sleeve, will a 1.25 OD tube with a .049 wall work well or should I use a 1.25 OD with a .058 wall?
Thanks in advance.
Brandon
For a sleeve, will a 1.25 OD tube with a .049 wall work well or should I use a 1.25 OD with a .058 wall?
Thanks in advance.
Brandon
#3
Senior Member
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,547
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 18349 Post(s)
Liked 4,502 Times
in
3,346 Posts
1.25 = 31.75mm
.049 * 2 = .098 = 2.49mm
.058 * 2 = .116 = 2.95mm
So, your sizes are:
31.75mm
29.26mm
28.8mm
So, looking at common seatpost sizes:
31.6 & 31.8 are available (no sleeve)
You can probably source 29.2 and 28.8 seatposts, or thereabouts, but they are less common.
Let's see:
(31.75 - 27.2) / 2 = 2.275mm ==> 0.0896 tubing.
So, you might do better with either no sleeve, or some pretty thick 0.089 tubing (27.2 seatpost).
.049 * 2 = .098 = 2.49mm
.058 * 2 = .116 = 2.95mm
So, your sizes are:
31.75mm
29.26mm
28.8mm
So, looking at common seatpost sizes:
31.6 & 31.8 are available (no sleeve)
You can probably source 29.2 and 28.8 seatposts, or thereabouts, but they are less common.
Let's see:
(31.75 - 27.2) / 2 = 2.275mm ==> 0.0896 tubing.
So, you might do better with either no sleeve, or some pretty thick 0.089 tubing (27.2 seatpost).
#4
Senior Member
Thread Starter
Thanks guys. I think I should have clarified that the sleeve will be for the outside of my ST. I'll have a 27.2 post.
#5
framebuilder
You need a 1 1/4" tube with a wall thickness of 0.058". If it is .049" there will be too much space between the inside of the bigger tube and the outside of the smaller tube for proper brazing clearance.
#6
Senior Member
Thread Starter
Thanks Doug. That's what I had figured. I have some here so that's good. Likely have it turned down just a tad for my liking.
#7
framebuilder
#8
Randomhead
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,385
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,686 Times
in
2,509 Posts
yes, turning it down is almost required, it's far too clunky otherwise.