bigger seat post, smaller seat tube
01-14-22, 08:55 PM
#1
Newbie
Thread Starter
Join Date: Jan 2022
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
bigger seat post, smaller seat tube
I bought a wrong seat post size, it’s 31.6 seat post. Is there any chance that I can use it on my 27.2 seat tube?
01-14-22, 08:56 PM
#2
SE Wis
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 10,516
Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970
Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 2747 Post(s)
Liked 3,401 Times
in
2,058 Posts
No
01-14-22, 09:57 PM
#4
Guest
Join Date: Sep 2020
Posts: 2,888
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 1346 Post(s)
Liked 3,270 Times
in
1,439 Posts
Just kidding.
You need a 27.2mm seatpost.
01-15-22, 06:22 AM
#5
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,547
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3674 Post(s)
Liked 5,437 Times
in
2,763 Posts
No
01-15-22, 09:07 AM
#6
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
In case you missed it, No.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
01-15-22, 09:57 AM
#7
Senior Member
Join Date: Jul 2013
Location: Nor-Cal
Posts: 3,767
Bikes: lots
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1958 Post(s)
Liked 2,932 Times
in
1,489 Posts
Just to make sure you didn't miss anything so far...NO. 
01-15-22, 10:09 AM
#9
Mad bike riding scientist
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,365
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
Mentioned: 152 Post(s)
Tagged: 1 Thread(s)
Quoted: 6219 Post(s)
Liked 4,219 Times
in
2,366 Posts
You might be able to slide the 31.6mm post over a 27.2mm post but that would be silly.
But, again, no.
But, again, no.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
01-15-22, 10:40 AM
#10
Advanced Slacker
Join Date: Feb 2017
Posts: 6,210
Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2762 Post(s)
Liked 2,537 Times
in
1,433 Posts
Sure. Just lube it up and push really hard.
01-15-22, 12:35 PM
#12
Senior Member
Join Date: Sep 2017
Posts: 7,887
Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 6972 Post(s)
Liked 10,968 Times
in
4,692 Posts
Likes For Koyote:
01-15-22, 12:50 PM
#13
Happy With My Bikes
Join Date: Sep 2020
Location: Oklahoma
Posts: 2,187
Bikes: Hi-Ten bike boomers, a Trek Domane and some projects
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 884 Post(s)
Liked 2,308 Times
in
1,118 Posts
If this is something you bought new from a retailer, just return it for a refund or correct size. As you just learned, with bicycles, the general standard is there are no general standards. Confirm measurements for everything. Chains, tires, handlebars, etc.
__________________
"It is the unknown around the corner that turns my wheels." -- Heinz Stücke
"It is the unknown around the corner that turns my wheels." -- Heinz Stücke
01-15-22, 01:29 PM
#14
I'm good to go!
Join Date: Jul 2017
Location: Mississippi
Posts: 14,992
Bikes: Tarmac Disc Comp Di2 - 2020
Mentioned: 51 Post(s)
Tagged: 0 Thread(s)
Quoted: 6196 Post(s)
Liked 4,810 Times
in
3,318 Posts
by the way,
Welcome to BF!
To answer your question, No!
Get the right size and don't cause yourself future grief.
Welcome to BF!
To answer your question, No!
Get the right size and don't cause yourself future grief.
01-15-22, 01:44 PM
#15
Banned
Join Date: Feb 2008
Location: Mississauga/Toronto, Ontario canada
Posts: 8,721
Bikes: I have 3 singlespeed/fixed gear bikes
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 4227 Post(s)
Liked 2,488 Times
in
1,286 Posts
Go visit a plumber, they will make it fit.
01-15-22, 01:57 PM
#16
Senior Member
01-15-22, 02:06 PM
#17
Clark W. Griswold
Join Date: Mar 2014
Location: ,location, location
Posts: 13,525
Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), R+M Supercharger2 Rohloff, Habanero Ti 26
Mentioned: 54 Post(s)
Tagged: 0 Thread(s)
Quoted: 4357 Post(s)
Liked 3,995 Times
in
2,666 Posts
I am going to disagree with everyone in this post and say YES but not in it's current form. You will want to melt it down to a more liquidious state and then use a funnel (one that can handle melted aluminum) and pour it in to your seat tube. Now of course you will need to pour carefully so you can still insert a proper 27.2 seatpost above should want to ride the bike.
Likes For veganbikes:
01-15-22, 09:07 PM
#18
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
If it's aluminum, OP could buy a $3000 lathe and cut it down to the right diameter.
It will then fit, although the wall thickness might make it too weak.
It will then fit, although the wall thickness might make it too weak.
I am going to disagree with everyone in this post and say YES but not in it's current form. You will want to melt it down to a more liquidious state and then use a funnel (one that can handle melted aluminum) and pour it in to your seat tube. Now of course you will need to pour carefully so you can still insert a proper 27.2 seatpost above should want to ride the bike.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Likes For Homebrew01:
01-15-22, 09:27 PM
#19
Senior Member
Join Date: Jan 2013
Posts: 2,681
Bikes: too many sparkly Italians, some sweet Americans and a couple interesting Japanese
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 584 Times
in
410 Posts
Almost forgot ,there is a long shot over on the Mountain Biking Forum there is a Mountain Bike Marketplace with a trade thread.
Last edited by easyupbug; 01-15-22 at 09:40 PM.
01-16-22, 04:12 AM
#20
Senior Member
Join Date: Jun 2013
Location: SW Fl.
Posts: 5,619
Bikes: Day6 Semi Recumbent "FIREBALL", 1981 Custom Touring Paramount, 1983 Road Paramount, 2013 Giant Propel Advanced SL3, 2018 Specialized Red Roubaix Expert mech., 2002 Magna 7sp hybrid, 1976 Bassett Racing 45sp Cruiser
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1069 Post(s)
Liked 788 Times
in
505 Posts
Likes For OldTryGuy:
01-16-22, 10:26 AM
#22
Senior Member
Don't listen to everyone else here! Go out and buy a tube expander from Harbor Freight. Seat tubes usually have enough material that they can safely be expanded by 4.5 mm.
OTOH, I don't expect even a newbie to buy that. The answer is still NO. Welcome aboard!
OTOH, I don't expect even a newbie to buy that. The answer is still NO. Welcome aboard!
01-16-22, 10:49 AM
#23
Advanced Slacker
Join Date: Feb 2017
Posts: 6,210
Bikes: Soma Fog Cutter, Surly Wednesday, Canfielld Tilt
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2762 Post(s)
Liked 2,537 Times
in
1,433 Posts
I think the OP has received a few great suggestions how to make this work.
01-16-22, 11:21 AM
#24
Duke Ulysses
Join Date: Jul 2013
Location: Southern California
Posts: 800
Bikes: An old orange one for dirt, and for the other stuff: a white one, a kinda mint green one, and a black one.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Liked 175 Times
in
86 Posts
Eddy could do it
01-16-22, 12:40 PM
#25
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,547
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3674 Post(s)
Liked 5,437 Times
in
2,763 Posts
If you return the seatpost to where you got it, especially with the saddle attached, your karma will be restored.