Hello all…
This is my first post. Ive searched this topic in the forums but couldnt find any info yet.
OK, I’m building a Lightspeed Saber frameset.
Question: Aero or no aero on the seatpost? It will be carbon I know that already.
Is the seatpost that much of a factor as far as drag?
Thanks a bunch.
If you have an older Saber w/o the integrated seat post…the answer is simple; a non-aero Thomson Elite or Masterpiece.
Repeat slowly: it is not about the bike… it is not about the bike… it is…
Position on bike: yes. Bike itself: totally unimportant.
Aestetics is something else, i´m all for that. Just don´t fool yourself into thiking you will go faster. You wont.
Axel
Is the seatpost that much of a factor as far as drag?
Thanks a bunch.
John Cobb tested aero posts in a windtunnel. His first test was on a bike with round tubing and an aero post, possibly a Giant TCR. His first test concluded they don’t work. His second testing concluded that they work with “some” people, I believe he wrote with skinnier legs. He felt they alway work best when the aero post is a continuaton as the same shape as an aero seat tube. It would look cooler on a Saber at least.
Pick the post you can get positioned the best on. The “aero” part of a seat post will just add weight and will probably make no impact on your time.
Use Alien TT is a good post. Very adjustable
Profile Design has a forward facing carbon
Some people like a little set back in the posts so that they ride shallow. What kind of bike are you riding? How are you positioned?
thanks all for the feedback !
Unless you’re missing out on being on top of the podium by fractions of a second, the aero post won’t matter at all. Aesthetically, yes, big deal then…so do what looks best and positions you properly.
I see a lot of hype on these forums about airflow over trivial areas, like housing, seatposts, etc. In reality, the drag effect is so minimal that your time is better spent on the road pedaling away than typing out questions on ST (not a personal dig, just saying in general). Working where I do, one of our competitors seems to foist upon the tri market the idea that you can buy measurable speed…
…I also happen to drop their round-tubed-Ksyrium-equipped-ti-Guru-tri-bike-infested group ride on my humble Madone rockin’ Tempests.
Anywho…as others have said, position > equipment. The single greatest improvement you can make is positioning yourself so you have a low frontal profile with optimal power output. That will far exceed ANY equipment-based speed you can EVER hope to see.
Disclosure:
I DO own a set of Zipps and FSA 56/44 lenticular rings, but they’re on my crit setup. So back off.
aero post looks cool.
Didn’t john cobb post it’s not that important a while back?
Either you know something we don’t or that was a poorly informed summary. The bike does make a difference but it depends on by how much and how important it is to you. Discounting materials and engineering design is basically rubbishing performance engineering (and in this case it’s comparable to motorsport with it’s demands and consdiration - when done properly).
Either you know something we don’t or that was a poorly informed summary. The bike does make a difference but it depends on by how much and how important it is to you. Discounting materials and engineering design is basically rubbishing performance engineering (and in this case it’s comparable to motorsport with it’s demands and consdiration - when done properly).
At race speeds, the bike accounts for such a small percentage of your aerodynamic drag that your drivetrain accounts for nearly as much of the net drag as your frame. Relative to each other, the frame matters more…but not in the total picture.If the Oval Concepts website is to be believed, then only 10% of your energy goes into overcoming drag from something other than your body, which accounts for aerodynamic AND mechanical resistance. Of that, your wheel choice is 15%, your drivetrain is 6% if I remember correctly, your handlebars are ~3%, etc.
When has talking faster actually made someone faster?
But you continue to worry about whether a set of 606s or 808s will be more likely to make that three hour drop from a 14 hour Ironman to 11 hours. I’ll continue training, thank you very much.
Sometimes the degree of misunderstanding that takes place on an internet forum is mind boggling.
UK Gear Muncher: The bike makes a small difference.
You: No, it does not make a huge difference!
Bikes, wheels, and even shoe covers make some difference in aerodynamic performance. Just because those differences aren’t meaningful to you doesn’t mean they aren’t meaningful to someone else.
“Unless you’re missing out on being on top of the podium by fractions of a second, the aero post won’t matter at all.”
Is that how you look at all your equipment choices?
The fact is that looking at the small savings that a specific change makes in isolation doesn’t really get you that far.
It is the collective effort to make every aspect of your machine as fast as possible that really matters.
Review some of the old posts by Jordan Rapp on here and you’ll find multiple examples of a person that is constantly seeking to maximize their aerodynamic advantage on the bike–no matter how small or trivial it may seem when viewed in isolation.
Either you know something we don’t or that was a poorly informed summary. The bike does make a difference but it depends on by how much and how important it is to you. Discounting materials and engineering design is basically rubbishing performance engineering (and in this case it’s comparable to motorsport with it’s demands and consdiration - when done properly).
At race speeds, the bike accounts for such a small percentage of your aerodynamic drag that your drivetrain accounts for nearly as much of the net drag as your frame. Relative to each other, the frame matters more…but not in the total picture.If the Oval Concepts website is to be believed, then only 10% of your energy goes into overcoming drag from something other than your body, which accounts for aerodynamic AND mechanical resistance. Of that, your wheel choice is 15%, your drivetrain is 6% if I remember correctly, your handlebars are ~3%, etc.
My brother (who should know better given his job in supersonic aerodynamics) made the same argument to me. I proved him incorrect by adding up the numerous small tweaks that I’ve done to my bike (neglecting position) over the last year. The net sum was about 5-7W at 20mph just by doing little stuff like paying attention to cable routing, bolt-on skewers, Visiontech base bar vs round, 80s style big brake levers vs VT levers, 20mm vs 23mm front tire, etc. Individually those changes are pretty small, but all of them added up made about a more or less free 2-3 minutes on a HIM course. It won’t put me on the podium by far, but it’s figuratively speaking low-hanging fruit…so why not pick it!!! Plus my consumerism helps to drive the economy!
Anyway, I use a Corima bladed forward seatpost and have been pretty happy with it once I replaced the crummy stock screw with a nice hard stainless one. I doubt that it makes much of a difference, but I have skinny legs so it might be marginally useful. It looks cool though, which is maybe the most important thing.
“The net sum was about 5-7W at 20mph just by doing little stuff like paying attention to cable routing, bolt-on skewers, Visiontech base bar vs round, 80s style big brake levers vs VT levers, 20mm vs 23mm front tire, etc. Individually those changes are pretty small, but all of them added up made about a more or less free 2-3 minutes on a HIM course.”
That’s interesting, my guess was that all the little things might get you 3-5W. Either way, I think the point is clear.
These are minor details at 20mph but becomes proportionally bigger at 22-24mph where I normally ride in a HIM. At a 24mph average it’s more like 24mph vs 24.5mph (similar time savings). Too bad I can’t yet put out 275W for 2:20! Of course when you are in the continuous on-your-left draft of being in the last wave start, it’s arguable whether aerodynamics really even matters.
A change in your rear tire from a high end Continental to a Vittoria or Veloflex will get you that much. Change both, and you’re already saving minutes on a TT course.
Chris
Even more if your baselining off a Tufo–which, if you read race reports around here, is a tire a lot of triathletes still ride!
That is sad indeed. I’ve bought 650c wheelsets off of two different people that came with Tufo S33s or Elites…I’m glad I got the wheels, but I think that people might have kept riding them had they known how much free speed was out there.
Chris
i just broke my kuota aero post by coming down on it too hard. fwiw. not sure what post you are looking at, but something to consider.