I want to buy a mountain bike soon and I’ve been doing a bunch or research. I noticed that some bike saddles can detach from the top of the saddle post, while others get removed with the whole post. There are a couple of things I want to know. Can all saddles be detached from the top of the saddle post? Are saddles that detach with the post of cheaper quality? that’s it, thank you
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3Would you provide a link to a picture of a saddle that seems not to detach from the post?– gschenkAug 2, 2020 at 8:10
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2Basically all of the saddles I've seen detach from the seat post. Are you thinking of seat posts with integrated clamps, vs the older cylindrical seatpost with a separate saddle clamp ?– Criggie ♦Aug 2, 2020 at 8:26
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1Hey guys. I realized that i wasn’t looking close at the saddles, and that they do actually detach. With a mix of a store employee telling me that I should detach the post in order to change the saddle. Thank you so much for responding, wishing you the best!– JoodAug 2, 2020 at 9:18
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1I've seen some very cheap bikes where the top of the seatpost was not your typical round knob but instead was flattened to allow the seat to be attached with a through-bolt. But this would be very unusual on anything other than a cheap kid's bike.– Daniel R HicksAug 2, 2020 at 12:45
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@DanielRHicks Yeah I used to have that on my old bike when I was 12/13, so that makes sense. Thank you for clarifying !– JoodAug 2, 2020 at 18:07
2 Answers
Saddles are always removable from the seatpost or, in some cases, the seat mast. I am not aware of any arrangements where the saddle is made in one piece with a seatpost or equivalent part. Because saddles are extremely personal, and even a rider's own saddle preference can change over time, it seems unlikely that there are such construction arrangements - I suppose a weight weenie cyclist might be willing and able to make or commission a saddle without rails bonded to a carbon seatpost or seat mast topper, but that would be very niche application. It would also be pointless, because most high end stock rim brake bikes and even a number of disc brake bikes can be brought under the UCI weight limit.
That said, a very small number of bikes have a seat tube that extends up from the top tube, which I believe is called a seat mast. You would clamp your saddle in a seat mast topper, then mount that on the mast. You would cut the seat tube to the correct length, and the mast topper offers a small range of height adjustment in case you need to change your saddle height. Probably the most prominent example is the Giant TCR, pictured below.
The picture is from this Velonews Q&A session with Lennard Zinn, where he fields a couple of letters from readers who are trying to extend a mast that had been cut, or else to just get a bit more saddle height than their cut mast allowed for. This neatly illustrates the potential downside of the seatmast design.
To the original question: in this arrangement, I suppose you could just remove the seatmast topper along with the saddle. However, the saddle is manufactured separately from the topper - or else how would you change your saddle horizontal position?
Why on earth would anyone make such an item? It could be lighter than seat tube and seat post arrangement, although remember that the impact of small amounts of weight on cycling performance are negligible. Open Cycles uses a seat mast arrangement on its Open MIND bike, and their webpage says that it allows them to make the seat tube very thin, at about 25mm - recall that a thinner tube should have more compliance than a thicker one, which should increase comfort. Alternatively, Speedvagen is a small batch steel frame builder, and as best as I can determine, the seat mast arrangement is an aesthetic choice only, and it's one of their signature design elements.
A 2008 article from Road Bike Action discusses some of the potential advantages of seatmasts, but I believe some of the arguments are incorrect (e.g. aerodynamic seat tubes and posts are more widely available today, although the post tends to be proprietary to each frame). If my memory is correct, seatmasts may have had a brief bloom in popularity in the late 2000s and early 2010s, but clearly they have not become widely accepted.
There are in fact Carbon seatposts with the saddle as one molded piece. Check out ControlTech for a good example.
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2Interesting - I can see three silver bolts going up into the saddle, so its clearly changeable, but has departed from the various common rail clamp systems to a literally-bolt-down design. Good find of a halfway variation, and welcome to the site!– Criggie ♦Feb 7, 2021 at 7:32
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Integrated seat+post are also very common in bmx racing. Most bmx mini seats are permanently integrated with the seatpost. Feb 7, 2021 at 7:41
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@Criggie here's one that is definitely a solid piece: instagram.com/p/CHVhWpAnn17– Paul HFeb 9, 2021 at 7:05
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@PaulH that's a good answer all by itself. Please post as an answer.– Criggie ♦Feb 9, 2021 at 9:07