Choosing a seatpost.
 

I see plain non-suspension seatposts ranging from $20 to $275. What could possibly explain this gap? What are the factors to consider when shopping seatposts?

A Zipp or Enve logo on the seatpost will command a premium price.

Form, Function and Price. You can expand the list beneath the first two. The third speaks for itself. Start with a realistic budget for that part.

Am I willing to go above $30? $50? More? So, now I can determine which other attributes I'm willing to buy as an extra.

Function: Correct diameter, degree of adjustability, material, weight, aerodynamics
Form: Style complement to bike (lines, coloring, cutouts, etc.) branding

Alloy vs carbon fiber, one-bolt vs two-bolt, degree of fine finishing, weight, aesthetics.

You should be able to get a perfectly good (light, strong reliable) seatpost for well under $100.

Thanks. What is the functional difference between one-bolt and two-bolt?

They are just different ways of adjusting the tilt...And I suppose the two-bolt will probably hold the tilt a bit more securely, which could matter if you are heavier and/or ride on rougher terrain. But in practice, they probably work equally well...And I actually find the one-bolt posts to be easier to adjust.

One bolt systems are indexed so if your ideal "tilt" is between index points you are forced to settle on the index either above or below your ideal point. Two bolt systems are not indexed and are infinitely more adjustable with regard to "tilt" position.

Two bolt is the way to go. If you don't need carbon, Thomson posts are some of the best around.

Campagnolo C-Record and Nitto S65 single bolt posts aren't indexed.

Campagnolo Record SP10-RE round post. Infinitely adjustable, holds its adjustment with low torque, correct diameter, shiny silver, worth the $100 used ones sell for. Also available with a discrete Record logo consistent with 9 speed ergo era aesthetics.

https://cimg9.ibsrv.net/gimg/bikefor...4cc647543c.jpg

Classic Campagnolo C-record aero post. Works like the later round version. Period correct for 1980s bikes. Available as a Record part with engraved shields plus collectable price tag and Chorus without.
https://cimg2.ibsrv.net/gimg/bikefor...5e7f976f17.jpg
Nitto S65. Mine needed 16 NM of torque to maintain its adjustment so I replaced it with a Campagnolo SP-10RE.
https://cimg8.ibsrv.net/gimg/bikefor...fdfa295b78.jpg

Rider weight pulls on the front bolt in 2-bolt systems which can lead to breakage:

https://cimg9.ibsrv.net/gimg/bikefor...385ee6ecbf.jpg

FWIW You can get a Zipp Service Course alloy seatpost for $40 with a Zipp logo on the side. It's probably no different than any other alloy seat post, but also... $40.
Carbon commands a premium price.

It was a generalization. But in the interest of accuracy, I am referring only to the $265 Zipp seatpost.

Weight, stiffness (or lack of), and looks

Good thread.

I generally prefer two bolt designs as offered by Deda or Thompson over one bolt designs like Ritchey or FSA because I find two bolt designs slightly easier to setup and slightly stronger. It's splitting hairs, though. The Pro Vibe captive expanding wedge design is also great.

Also, long, flexy D-shaped carbon posts are awesome.

Here ends seatpost talk with Hiro11.

There are many different types of clamping systems, even within the general 1-bolt and 2-bolt categories, and the good thing is that, generally, they all work just fine. The 2-bolt concept grew out of the demands of MTBing and do offer superior clamp security. so if you’r going to be riding in a way that stresses the clamp, you want to thinking about that.

For typical road riding though, it’s nothing to worry about, and the biggest issue with the postis that you get the adjustment range you want, particularly since many saddles have shorter rails nowadays. You’ll notice some posts have the clamp area centered directly on the centerline of the post— this is zero setback— while others have the clamp offset from the centerline of the post, known as setback. Depending on where you want your saddle relative to the pedals and how much seat rail you have to work with, setback may be preferred.

Another consideration in posts is length, so be aware of that.

Material construction can be a big deal depending on what you’re looking for. Carbon fiber are the lightest generally, while titanium can be quite flexible, helping to smooth out bumps. Because of variability in size diameter and extension length, that’s master level stuff, though, and probably not something to bother with for someone who has never thought about posts before.

Personally, weight, style, and price are the big three factors for me, and I try to buy as light and cool as I can afford. FSA SL-K Setback carbon fiber posts fit the bill often for me apparently, as I have two, but I also like Deda’s single bolt road styling and USE’s unique Alien single bolt styles as well. I think titanium is the best post material by feel, and would run it more often if producers offered black anodize or some styling elements beyond natural ti color brushing, bead blasted, satin or whatever.

I have a cheap Kalloy post where the internal bore was way off of being concentric. Pretty sure it was unintentional. Like anything else in cycling, the high end gets you very marginal gains for a lot of extra cost. But the difference in quality between the cheapest and the mid-price option can be quite large.

I have and have had many seat posts over the years. Infinitely adjustable posts are my preference as I can get saddle tilt exactly perfect. Currently have two of the Nitto single bolt posts and they do require a lot of torque to secure the clamp. The Campy C Record is excellent as well with the bonus of not requiring as much torque to secure the clamp as the Nitto. Once had a cheap Asian carbon post that served well for about 8 years until the clamp fractured. The clamp was aluminum and it simply cracked from the load I put on it.

My personal favorites are an equal toss up between the Nitto, C Record, Velo Orange Gran Cru, and the good ol' Nuovo Record two bolt post. All three seem exceptionally durable, have at least 25mm of setback with the Gran Cru at 30mm, and they all look great. Weight? Light, strong, inexpensive. Which two do you want?

I prefer the controlled adjustability of two bolt seatposts -- I don't think anyone has mentioned that so far. With a two bolt system, you can loosen one bolt, slide the saddle fore or aft, and tighten that one bolt: tilt stays the same. Or you can loosen one bolt and tighten the other to adjust the tilt -- fore/aft position doesn't change. Adjustments are precise.

Contrast that to my experience with one bolt systems. Loosen the bolt until things can move. When you get the bolt loose enough, everything is in play. I've gotten the tilt right only to mess up fore/aft, and vice versa. Adjustment is more of an accuracy thing; it's like learning to shoot a bow and arrow. Miss right? Go back and shoot again, it may be left, up, or down from the bulls-eye. Keep shooting (or adjusting) until you get lucky and hit the bulls-eye, or get tired and call it quits.

Drew's picture surprised me. I haven't had a failure like that on any of my two post seatposts. I guess that was a latent manufacturing defect -- nasty surprise when it failed, I'm sure!

My 1970 Campy post was two bolt.

Yeah, being able to independently deal with rail clamping force and saddle tilt makes everything a bit easier. Also, I've found two bolt seat posts are less likely to creak.

True. Actually, my favorite clamp design of all time is this cheap $20 "Forte Team" seat post from the old Performance Bike:
https://www.ebay.com/itm/28394607200...EaAjmjEALw_wcB

The bolt on the side independently adjusts rail clamping force. Once you've clamped the rails, the bolt on the back of the post then independently secures the saddle tilt. This makes it a snap to set up and it doesn't creak. I've never seen another post use that design.