Could be a fun thread…

I noticed a lot of new bikes on the market have oval shaped seat post. A couple of manufacturers had started doing that in the last couple of years.

I know head tubes had gone oval for a while. The excuse was “aero”. Put aside the reality of most people not racing probably aren’t riding their bikes fast to benefit much from it, I doubt the aero benefit extends to seat post. More to the point, manufacturers aren’t claiming it for aero benefits either. Bike shops sales came up with all different guesses. None are terribly convincing.

So, I wonder what’s the motivation behind. What have you heard? And are you convinced by those reasons?

"Oval" is more aerodynamic than round. It might be a small effect, but it's a real thing.

Obviously - its for big bike to make proprietary parts that will become obsolete/no longer produced, forcing you into buying the next bigger better faster bike with even more proprietary parts and pieces.

It's probably close to undetectable. For the vast majority of riders, it's not a "real thing" at all..

ever heard the phrase "vertically compliant but laterally stiff"?

Locks you to buying OEM parts !
I needed a “D” shaped zero offset seatpost, cost $250 and came without the clamp.

Just Wow

Barry

Many, many technological details are undetectable by most cyclists. That doesn't make them any less real.

It is real for the vast majority of riders who believe it is real.

#Marketing

Most all of those bikes you are looking at with aero shaped seat posts are going to be the higher end road bikes. Though certainly bikes made specifically for time trials and triathlon will have aerodynamic tubes too. And aero forms are moving down into the lower cost tiers of road bikes as well.

The name road bike shouldn't imply that they should be a first choice for everyone that has the intention of riding on the road. Road bikes are intended to be for higher effort cycling and longer distances. A better bike for just riding a short distance will be the cruiser style bikes. Ones with very slack seat tubes and swept back bars.

Road bikes have that aesthetic look that draws many people to them even though they will be better served by a different bicycle type.

Yeah, but there’s a down side (EVERYTHING has down sides!). Oval is not as strong as round shape for the same size. So they had to put more material to achieve the same strength. Otherwise, the seat post will be weaker as a result, increasing potential of broken seat post for heavier riders.

Remember way back when, bikes came with increasingly deeper dish rims? Well, they backed away from that when people got blown sideways by cross wind. Only in that case, it’s the little guys who experienced the problem the worst.

To answer the question in the thread title: proprietary seatpost shapes were developed by Big Bike, conspiring with social media cycling site owners, to generate thread traffic by giving certain posters yet another thing to complain about. Everybody wins!

The effect might not really be "real" (measuarble) for any cyclist.

Oval seats posts don't weigh any more than round seat posts, and they're no less strong.

By putting "real" in quotes, I can only guess you're using your own definition for the word. I'm not interested in debating someone that redefines words.

No, I'm suggesting that what you are saying is mostly BS.

You think it's BS that an oval tube is more aerodynamic than a round tube? Or that it's a small effect? That's the only two points I made.

You are definitely not following some very basic stuff.

It's possible there is no detectable difference with a rider on the bike. (Maybe, there could be a detectable difference with it isolated in a wind tunnel but that might not translate to a real benefit in the real world at all.)

Again, which of the two statements is BS?

1. An oval tube is more aerodynamic than a round tube.
2. The above is a small effect.

Those dang engineers and scientists aren't testing that stuff in a wind tunnel for perceive-ability they only test for aerodynamic affects those fools.

Re-writing the law of physics?

Not at all. Oval seat posts can be designed to be just as strong without increasing the weight.

The only thing I like about oval or D-shaped seatposts is that you never have to worry if your saddle is pointed straight. Other than that they are an expensive solution to a nonexistent problem.

You can say that about the majority of changes to bicycles (or any product) over the years. But, that doesn't mean those changes don't offer benefits.

Like exactly how?

Just to make clear the expectation. I’m a physicist by training. But I’m ready to listen to a mechanical engineer, especially one with working experience in material science.

If you already have an oval seat tube, it may be simpler to engineer an oval post for it than a cylindrical one, and bike companies are building bikes to sell new, not to be useful to the second owner because that makes the zero dollars. So, the question isn't necessarily whether there's any real aerodynamic advantage for the mythical Average Rider, but rather whether there's any advantage to the bike company in spec'ing a round seatpost that is unarguably less aerodynamic.