Bicycles Stack Exchange
Bicycles Stack Exchange

Questions tagged [seatpost]

Questions referring to the part of a bike that extends upward from the seat tube on the frame to the saddle.

238 questions
14
votes
4 answers

How to stop bike renters overextending seatposts?

A friend and I have been operating a bike rental shop for about a year, and just recently we've started to notice more and more customers extending the seatpost well beyond the maximum line. So far we haven't had any frame issues, just bent…
user49173
  • 159
  • 1
  • 3
13
votes
3 answers

Safely cutting down a seatpost

I want to shorten my seatpost it fouls the non-OEM kickstand on my folding bike when lowered. What is the best way to cut a (33.9mm alu) seatpost? Can I just use a rotary plumbing pipe cutter? The edges of a seatpost appear to be deburred or…
RoboKaren
  • 29,248
  • 17
  • 91
  • 174
8
votes
7 answers

Problems with a slipping seatpost

I got a Cannondale Quick1 2010, with the seatpost made with aluminium carbon-wrapped. The problem is that the seatpost tends to slide downwards, even if I squeeze a lot the snap ring; if the ground is uneven the seatpost slips completely. Is there a…
Sam Qasbah
  • 181
  • 1
  • 1
  • 3
7
votes
2 answers

Copper pipe seatpost?

I have a 12 inch wheel girls bike with no seatpost. It turns out a 1 inch diameter copper water pipe fits. I know I could take some time and find a steel post but in this case does it matter? The seat will never be raised more than an inch or two.
David D
  • 21,204
  • 1
  • 27
  • 87
7
votes
2 answers

Before re-inserting a stuck seat post what should I do to the steel/alloy surfaces?

After several days and great effort I've succeeded in removing a stuck seat post (alloy post in a steel frame). It's actually in a reusable condition. Before trying to re-insert it, what should I do to the steel/alloy surfaces - apart from a proper…
Jeremy Boden
  • 201
  • 1
  • 5
5
votes
3 answers

Reversible but not symmetrical lower plate in seatpost

I have an old seatpost that was removed from its original bike quite some time ago, now I want to use it in another bike, but I don't know if the lower plate should be positioned so it extends behind the top plate or so it extends in front of the…
hmqcnoesy
  • 285
  • 1
  • 6
5
votes
5 answers

Why did the bike shop put grease on my seatpost?

When I bought a new bike my LBS put grease on the part of the seatpost that inserts into the frame. Why is this? Surely it can't seize?
Mark W
  • 1,811
  • 3
  • 19
  • 30
4
votes
1 answer

Seat post shims

I have 3 bikes (2 mtb 1road) all with different seat post diameters. Has anyone used shims. I have 1 favorite saddle. I can buy 2 shims for the fraction of the cost of new saddles. Just switch seat and post in seconds. Quick angle adjust when…
Fat and slow
  • 41
  • 1
4
votes
1 answer

What does this rod inside the my american classic seat post do?

I've got an american classic seatpost. I bought it used, and wasn't sure how to properly adjust it initially. I found the bolt on the bottom clamps the seat down. The bolt on the rear underside adjusts the saddle angle. But the bolt on the front…
Benzo
  • 18,185
  • 29
  • 106
  • 172
3
votes
2 answers

How to measure seatpost length

What are the standard measurement points for seatpost length? I am buying a new seatpost, and need to compare my old post to the "marketed" length of possible replacement posts to make sure I don't buy one that's too short. Options include: The…
Chris Keefe
  • 155
  • 6
3
votes
2 answers

How to calculate how strong is seat post?

Is 27.2mm seat post stronger than 25.4mm because it has bigger diameter? How to mathematically calculate how much 27.2mm stronger than 25.4mm provided both seat posts have same length, wall thickness and made of same metal? If i have to use 25.4mm…
LilBro
  • 564
  • 2
  • 14
3
votes
2 answers

Adjusting the saddle angle on a single bolt saddle clamp without grooves

I am about to buy a new seat post on the Internet. Looking at the pictures, the saddle clamp has a single bolt, but I can not understand how it could adjust the saddle angle. The seat post I currently use has these grooves on the saddle clamp, so…
fabda01
  • 209
  • 1
  • 4
3
votes
2 answers

How to repair / create a CF seat post clamp interface?

I have a carbon Trek Madone 4.7 road frame with a nonexistent clamp interface. At the top of the seat tube, there should be a smaller-radius section of notched aluminum on which to place a clamp. That part of my frame is missing. The top of the…
Alex
  • 301
  • 2
  • 13
3
votes
3 answers

Getting the right seat post

I'm currently rebuilding an old steel frame. After measuring it I was sure it'd take a 27.2mm seat post (see picture) so that's what i bought. Sadly it doesn't fit (despite some "encouragement" with a mallet). So I'm now in the position of needing…
Darren L
  • 219
  • 4
  • 9
3
votes
3 answers

Dual water bottle brackets on a single frame mount?

I'm looking for a way to mount two water bottle cages on the seat tube. Is there any way to make this hold two water bottle cages on one bracket / mount point?
Gregory Schultz
  • 133
  • 5
1
2 3