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TheCharm 08-08-20 07:15 PM

Differences in seat post quality
A while back when I got a proper fitting on my Surly Disc Trucker, my fitter recommended replacing my seat post. I didn't need the setback my stock one provided and he preferred one with a two bolt configuration to hold the seat, not a single bolt. He suggested a Soma ZERO (no setback). It's fine seatpost, though it's a part I don't really think about.

Well, the pandemic has given me a bit more time at home to revamp my 2011 Trek 7.3FX -- swap parts that are worn, etc. Of course that's a challenge in an of itself because lots of parts are unavailable/sold out. I've had mostly good luck, despite it all. I want to swap my seat post to a no setback one, as it would move me closer to a more optimal fit for me on that particular bike. Of course that Soma one is sold out everywhere. The only other brands I really know are Thomson and Ritchey. An equivalent Thomson is around $135. My Soma was no more than $30 as I recall. Of course, plenty of online stores have Thomson posts in stock.

I'm rarely one to complain about the price of bike parts as owning a bike is in every way possible less expensive than car ownership. But can someone help me understand what a seatpost like the Thompson will give me that others won't? I've spent a considerable about of time (and $$) buying tools and trying to learn how to be a better mechanic. Along with this, I find I'm taking considerable time to compare parts and make good selections. When I used to leave things to the LBS, they usually throw on the basic of whatever they have. I never knew enough to specify a quality level or what have you.

Finally, do you have some recommendations of seat posts I should look at? I'm looking for what I think is a fairly standard size of 27.2/350. the most important aspect besides no set back and two bolt configuration is that it is available now.

Thank you for any comments.

Andrew R Stewart 08-08-20 08:09 PM

Material quality, tolerance control, finish, replacement parts, marketing, ego bling, weight. Andy

cubewheels 08-08-20 08:18 PM

At 27.2, definitely avoid setback especially for alloy, they are prone to bend especially cheaper ones if you ride over poor quality roads.

Even a very slightly bent seatpost even if unnoticeable for many years can be troublesome as they can get stuck in the frame. Most stuck seat posts are due to very slightly bent seat post or slightly bent frame / seat tube.

Personally, I'd love to have a two-bolt chromoly (or high tensile) steel seat post but I never see any of these anymore :(

Thruhiker 08-08-20 09:26 PM

All of my bikes use 27.2 post size. 3 are made for that size and the couple mtb that are 30.4 I use a shim. Ever one is set back. I have never bent a seat post and am 250 pounds. I ride rough roads,single track, cow pastures and fire roads. I am not gentle on my bikes. I have a thompson elite on my touring bike and bought it only for the name. I also have Zipp and Velo Orange gran cru. Those are the only ones that i have that are name brand, the rest are unbranded as cheap as I can find. The velo is not a two bolt design. It does use 2 bolts but not to adjust the plane of the seat. Imo the Thompson is the best seat post there is, certainly the best I own.

DrIsotope 08-08-20 09:41 PM

A Thomson is a seatpost you need only buy once.

TheCharm 08-09-20 04:50 AM

Cool - thanks for the comments. Thompson posts are available, so I might bit the bullet.

Tandem Tom 08-09-20 05:25 AM

I recently bought a VO Setback but was not aware that I could not micro adjust it. Bought a Thompson Elite.
I had to pay full retail in ebay as I work in a bike shop and our suppliers are out of them!!

HillRider 08-09-20 06:59 AM

I have Thomson "Setback" (read: intentionally bent) seatposts on two bikes, one 27.2 mm and the other 31.6 mm, and they have been great and worth the extra cost. The saddle angle adjustment is very easy and secure and, since they are a one-piece design, there is no possibility that the saddle clamp will separate from the post.

As to bending a 27.2 mm, or even thinner, setback seatpost, I've never done it or know anybody who has. It would take a very heavy rider hitting a huge bump and that would probably damage more than just the seatpost. And, no, most stuck seat posts aren't bent, they are corroded.

shelbyfv 08-09-20 07:35 AM

Another good thing about the Thomson post is they are easy to sell if your needs change.

DrIsotope 08-09-20 08:23 AM

I can attest to that. The used ones go for about 80% the cost of new ones.

davidad 08-09-20 09:29 AM I have one on each of my bikes. The road has 122,000 miles on it and it still looks good. A two bolt seat post is ideal for a Brooks saddle because the angle adjustment is very important to the nether regions.

fietsbob 08-09-20 10:20 AM

Make sure your seat tube wont scratch the new seat post to preserve it's resale value..
smooth any burrs.

Drew Eckhardt 08-09-20 12:22 PM

There's a difference which doesn't necessarily correlate to price.

I broke the original front saddle clamp bolt in 3400 miles and stronger replacement in 1700 on a Velo Orange two bolt post where they were too small.

My Nitto S65 required 16 NM to hold its angle adjustment.

One of those required excess seat clamp pressure to maintain height.

I broke the cradle on a Campagnolo titanium seatpost.

After that I gave up and bought an old 1996-1997 Campagnolo SP10-RE seatpost using the same clamp assembly as the venerable C-Record aero post I used before trying various round seatposts.

Those are true to size and maintain their adjustment with minimal torque on the saddle clamp bolt.

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