Seat post size
06-19-15, 03:28 PM
#1
Senior Member
Thread Starter
Join Date: Aug 2014
Location: Bronx, NYC
Posts: 1,939
Bikes: '19 Fuji Gran Fondo 1.5, '72 Peugeot PX10, '71ish Gitane Super Corsa, '78 Fuji Newest, '89 Fuji Ace, '94 Cannondale R600, early '70s LeJeune Pro project
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 292 Post(s)
Liked 217 Times
in
100 Posts
Seat post size
This is a very simple and straight forward inquiry but I want to be certain before buying a new seat post for the '73 Raleigh Super Course that I am building up. The original hollow seat post is 26.3mm but that seems to be a very uncommon size and I want to replace it with a seatpost that does not require the attachment for the saddle. I see many 26.2 options such as a Kalloy. Now eould this .1 mm be an issue or could I just use a 26.2? Thanks!
06-19-15, 03:31 PM
#2
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,360
Bikes: Several, mostly not name brands.
Mentioned: 149 Post(s)
Tagged: 0 Thread(s)
Quoted: 3313 Post(s)
Liked 2,795 Times
in
1,613 Posts
Seat posts a sized in 0.2mm increments, so you likely need either a 26.2 or a 26.4. Are you measuring the OD of the post or the ID of the seat tube? if the post, measure in several places and several orientations. If the seat tube, measure a couple different orientations, as brazing heat often causes the top of the seat tube to become slightly oval.
06-19-15, 03:36 PM
#3
Senior Member
Thread Starter
Join Date: Aug 2014
Location: Bronx, NYC
Posts: 1,939
Bikes: '19 Fuji Gran Fondo 1.5, '72 Peugeot PX10, '71ish Gitane Super Corsa, '78 Fuji Newest, '89 Fuji Ace, '94 Cannondale R600, early '70s LeJeune Pro project
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 292 Post(s)
Liked 217 Times
in
100 Posts
I measured the post so I will measure it in a few more spots. Obviously round down when buying the post right?
06-19-15, 06:02 PM
#4
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,176
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 132 Post(s)
Tagged: 1 Thread(s)
Quoted: 5029 Post(s)
Liked 1,150 Times
in
672 Posts
the bike was likely built in the UK while on the imperial system and the post is 1-1/32". Seat tube is 1-1/8" with 3/64" wall thickness.
Your decision should be based on how the current post fits. If it's a very snug fit, you have no upside room and should go with a 26.2. If it's free running fit, with maybe a bit of jiggle, go up to 26.4. If you go up, you can safely ream the tube out to a perfect fit.
Your decision should be based on how the current post fits. If it's a very snug fit, you have no upside room and should go with a 26.2. If it's free running fit, with maybe a bit of jiggle, go up to 26.4. If you go up, you can safely ream the tube out to a perfect fit.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
06-26-15, 03:12 PM
#5
Senior Member
Thread Starter
Join Date: Aug 2014
Location: Bronx, NYC
Posts: 1,939
Bikes: '19 Fuji Gran Fondo 1.5, '72 Peugeot PX10, '71ish Gitane Super Corsa, '78 Fuji Newest, '89 Fuji Ace, '94 Cannondale R600, early '70s LeJeune Pro project
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 292 Post(s)
Liked 217 Times
in
100 Posts
@FBinNY I measured numerous times and it turns out that it is 26.4 mm. I bought a Kalloy post and it fits snugly. Thank you.
06-26-15, 05:58 PM
#6
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 11,851
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: 120 Post(s)
Tagged: 0 Thread(s)
Quoted: 4151 Post(s)
Liked 3,143 Times
in
2,040 Posts
To add to what FB says: another option is to get a 26.4 post, try it and emery cloth it down until it fits. (I did this with a Kalloy27.s post to get to the 27.0 of my Raleigh Competition. Wasn't hard. I put it in a bench vise and tried it frequently.)
Ben
Ben
06-26-15, 05:59 PM
#7
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 11,851
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: 120 Post(s)
Tagged: 0 Thread(s)
Quoted: 4151 Post(s)
Liked 3,143 Times
in
2,040 Posts
Ben
