The hierarchy of aero

Triathlon Forum
1

I would like to get thinner to the wind, and I would like the ST experts to rank the following factors from most aerodynamically impactful to least:

A rider position
B rider body shape
C bike frame
D wheels
E helmet
F shoes
G bottle between bars
H bottle on down tube
I bottle on seat tube
J bottle(s) behind saddle
K fork
L cables
M tires
N bars

(FWIW, I race on a round-tubed road bike with fastforward seatpost, tristryke saddle, old borrowed airstryke bars with profile bottle, flo 60/90 set. And I race in a road helmet with vents taped shut (race-day temps permitting). But please rank them objectively as if you were starting from scratch, not according to my particular setup. thanks.)

2

1.Rider position (depending on how much and what you change)
2.Aero wheels
3.Aero Helmet
4.Aero Frame/Fork

these are the most significant things the others are minor.
body shape takes a long time to change.

3

I would say
Rider position
Aero helmet
Wheels
Frame

My guess is rider position is 70% of the total, so more important than the others combined. Only problem is position requires wind tunnel testing, the others are generally more easy to measure, except for the “best” helmet, but an aero helmet will usually be faster than a road helmet, no matter which one you choose.

4

also depends what distance you are racing being in a aero as possible position wont make you any faster if you are not comfortable
.

5

Funny…but there seems like an inverse relationship with the $ spent vs. actual benefit. Body positioning and helmets generally trump frames and wheels.

6

If you’re really on a budget, I’d further break the wheels up. The front wheel is much, much more important than the rear.

7

http://i48.tinypic.com/2qw32b7.jpg

Don’t forget the field of Facial Aerodynamics. There was a very detailed study done a few years back, the URL escapes me now, but I believe the picture up top represented the better findings.

8
  1. position
  2. tires (if you inlucde CRR)
  3. the totality of not having a bunch of shit hanging off your frame
    4/5: frame/wheels (tie?)
  4. helmet
  5. cockpit
  6. fork
  7. cables
  8. shoes

I would like to get thinner to the wind, and I would like the ST experts to rank the following factors from most aerodynamically impactful to least:

A rider position
B rider body shape
C bike frame
D wheels
E helmet
F shoes
G bottle between bars
H bottle on down tube
I bottle on seat tube
J bottle(s) behind saddle
K fork
L cables
M tires
N bars

(FWIW, I race on a round-tubed road bike with fastforward seatpost, tristryke saddle, old borrowed airstryke bars with profile bottle, flo 60/90 set. And I race in a road helmet with vents taped shut (race-day temps permitting). But please rank them objectively as if you were starting from scratch, not according to my particular setup. thanks.)

9

http://www.socalttseries.com/p/time-trial-aerodynamics.html

Aerodynamics for Time Trial Racing - Where to invest upgrade dollars when considering new equipment and gear.

10

I haven’t seen anyone mention skin suits, but some of the most dramatic improvements we’ve seen (other than positioning) were due to changing from shiny short-sleeved kit into long-sleeved, textured skinsuits.

“Skin is slow.”
– Paul Harder, Trek Engineer

11

What are some brands/models that are pretty legit that you have seen?

I just have a basic champsys. If I went fancy would I break the sound barrier?

I haven’t seen anyone mention skin suits, but some of the most dramatic improvements we’ve seen (other than positioning) were due to changing from shiny short-sleeved kit into long-sleeved, textured skinsuits.

“Skin is slow.”
– Paul Harder, Trek Engineer

12

the basic champsys was slower for me than the team run of the mill suit.

the thought was the texture all the way along the flat torso/back was texture in the wrong place

13

What are some brands/models that are pretty legit that you have seen?

I’ve personally seen good improvements with one of the newer Champ-Sys cycling speed suits, although I’m not sure if it’s out yet. And the Pearl-Izumi Octane trisuit tested pretty well, too.

For a more complete list I’ll defer to Jim Manton, who has probably seen a lot more tests.

14

Only problem is position requires wind tunnel testing

Not.

Though it is hard to do accurately without a PM. But even then you can look at frontal area and smart practices.

15

“Skin is slow.”
– Paul Harder, Trek Engineer

Hairy skin is probably worse…

I have a textured Voler suit… but it doesn’t seem to be any lower drag than my old and smooth ones. I’d happily spend $300 on a new suit if I thought it would reduce my CdA by 5% or better.

16

PositionClothingHelmet or WheelsHelmet or WheelsClean front end (i.e.cables)Proper hydration setupFrameCastelli Body Paint II seems to be very consistently fast. Champion Systems is coming out with a VERY good skin suit. For tri, you’re giving up minutes if you’re not using a Pearl Izumi Tri Octane. Seriously, that suit is amazing.

17

PositionClothingHelmet or WheelsHelmet or WheelsClean front end (i.e.cables)Proper hydration setupFrameCastelli Body Paint II seems to be very consistently fast. Champion Systems is coming out with a VERY good skin suit. For tri, you’re giving up minutes if you’re not using a Pearl Izumi Tri Octane. Seriously, that suit is amazing.

Always listen to the best bike fitter on the planet! Jim set me up in a perfect tt position, one I’ve been able to ride in for rides as long as 138 miles with very minimal time out of the extensions.

Now I need to work on the motor…

18

Can you point out key differences between the Pearl Tri Octane suit and a skin suit? It looks like they are close to one in the same.

19

Castelli Body Paint II seems to be very consistently fast. Champion Systems is coming out with a VERY good skin suit. For tri, you’re giving up minutes if you’re not using a Pearl Izumi Tri Octane. Seriously, that suit is amazing.

Have you tested the LG Course TT skinsuit?

20

Funny…but there seems like an inverse relationship with the $ spent vs. actual benefit. Body positioning and helmets generally trump frames and wheels.

Maybe… better positioning isn’t necessarily free, depending on where you start and what sort of equipment choices may facilitate positioning improvements. It could be as simple as moving your saddle forward and/or flipping the stem/spacers; or, it could lead to new saddle, bars/stem, even a new frame, etc. I was kind of at the limit of where I could get with my old converted road frame & bent forward seatpost, for example, so buying a TT/Tri-specific frame accomplished both position gains as well as reduced drag of the frame itself.