How are seatposts measured?
#1
The Legitimiser
Thread Starter
Join Date: Jul 2005
Location: Southampton, UK
Posts: 4,849
Bikes: Gazelle Trim Trophy, EG Bates Track Bike, HR Bates Cantiflex bike, Nigel Dean fixed gear conversion, Raleigh Royal, Falcon Westminster.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 5 Times
in
4 Posts
How are seatposts measured?
I need to put about 40 mm more in length on my seatpost for the R20, and the longest seatpost I can find online is 400mm. If that's a measurement of how much exposed seatpost you can have, then it'll be plenty, but I'm not sure what the length measures on seatposts actually refer to. Does anyone here?
#2
Senior Member
Join Date: May 2005
Location: Albany, WA
Posts: 7,393
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Likes: 0
Liked 7 Times
in
6 Posts
Usually from the very bottom to the saddle rails. 400mm is very plenty, I used 350mm and it was very plenty. Currently I am using a 400mm Thudbuster and it is 'quite far' above the minimum mark.
#3
The Legitimiser
Thread Starter
Join Date: Jul 2005
Location: Southampton, UK
Posts: 4,849
Bikes: Gazelle Trim Trophy, EG Bates Track Bike, HR Bates Cantiflex bike, Nigel Dean fixed gear conversion, Raleigh Royal, Falcon Westminster.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 5 Times
in
4 Posts
Are you 6'3 though?
#6
Senior Member
Join Date: Jun 2005
Location: Angus, Scotland
Posts: 406
Bikes: Many
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Cut up an old frame they are 28.6mm external diameter on the seat tube. Slot that in the frame. Use the seat pin from the cut up frame. Ive done that on my Raleigh Grifter.
#7
Senior Member
Join Date: Mar 2005
Location: Portugal-Israel
Posts: 863
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#8
Raleigh20 PugFixie, Merc
at 5'5" I have to agree. Makes for lighter bikes too woo!
__________________
My Raleigh Twenty site | foldr : A flickr pool | #6460, #5632 & #3407 on the fixedgeargallery
My Raleigh Twenty site | foldr : A flickr pool | #6460, #5632 & #3407 on the fixedgeargallery
#9
The Legitimiser
Thread Starter
Join Date: Jul 2005
Location: Southampton, UK
Posts: 4,849
Bikes: Gazelle Trim Trophy, EG Bates Track Bike, HR Bates Cantiflex bike, Nigel Dean fixed gear conversion, Raleigh Royal, Falcon Westminster.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 5 Times
in
4 Posts
#10
Senior Member
Join Date: Sep 2004
Posts: 244
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
You don't need to cut up an old frame. For a seatpost that long I'd buy some 1 1/8" OD steel tubing with a 1" ID. Aircraft Spruce (https://www.aircraftspruce.com) is a good source of this.
You can then pin a 1" seatpost in the top of that. This makes a very long 28.6mm (1 1/8") seatpost. You can use stainless steel or have the tubing nickle plated.
This is how the seatposts were originally made for the steel NY Swift Folders.
This will give you a much stronger seatpost than cutting out an old frame tube. The frame tube will likely be .6mm for most of it's length, butted to .9mm at the base (where you don't need the extra strength). The tube that I suggest will be 1.6mm wall thickness.
You can then pin a 1" seatpost in the top of that. This makes a very long 28.6mm (1 1/8") seatpost. You can use stainless steel or have the tubing nickle plated.
This is how the seatposts were originally made for the steel NY Swift Folders.
This will give you a much stronger seatpost than cutting out an old frame tube. The frame tube will likely be .6mm for most of it's length, butted to .9mm at the base (where you don't need the extra strength). The tube that I suggest will be 1.6mm wall thickness.
#11
Junior Member
Join Date: Jun 2006
Location: New Zealand
Posts: 107
Bikes: Diamond Back Apex, Raleigh 20, Raleigh Sports
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
"You can then pin a 1" seatpost in the top of that."
>>how would you do this?
>>how would you do this?