Wrong. It could have a substantial aero impact. I talked about this a lot here

Unless you need serious reach or to lower your stack significantly with something like the Syntace Flatforce, there is no reason to buy this bar or use an undermount setup given that TriRig has the low stack, in-line extension clamps for the Alpha X.

I would love to put data behind your question, though. I just don't see how adding all that frontal area doesn't have a material aero impact. It would be fascinating to tunnel test the Alpha X in undermount, in-line, and overmount setups. I wouldn't be surprised if we're talking about several watts difference.

Thanks - yes my main reason is to lower the stack. My current bar is the 3T aduro with the low mount (not the ultra low which was recalled and is out of circulation), and while my position is "ok" it would be better with a lower stack. I didn't know about the Syntace Flatforce - that looks like it could be a good option to lower the stack but keep the hardware mounted above the base bar - is that what you're saying?

I really like the simplicity and clean lines of the 3T aduro - it just doesn't have an option to get nice and low.

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

Rob, it looks like the left position for your body will be lower and wider and the right postion higher and narrower....but I thought there is a limit to narrow because the air still has to go around your hips, so it's a matter of which position deflects it better on the width front and then if the higher position for shoulders ends up being better or worse (likely worse for height, better for narrow).

My point was a little different. I can hit numbers using the Enve undermount with an aggressive stem like the Syntace that I cannot hit with a bar like the Alpha X that has a built in stem. That the Enve bar is a two piece, standard clamp design opens up more possibilities.

But I agree with where you went with it. I would absolutely get lower via an aggressive stem before resorting to the undermount configuration. I just don't believe it's as fast, especially when it's the Enve undermount, which has all that tilt hardware that seems to add a lot of frontal area.

Eyeball aero isn't reliable of course, but I would never go undermount if I didn't absolutely have to. Here are some pics. You be a judge of what you think looks fast, relative to the others:

Thanks Dev yes, the higher position does allow a more narrow pad setup. Plus I think I can "turtle" to get aero enough even with the higher stack. All that stuff under the bar bothers me a lot with the low option

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

Rob, what's the frontal area add from the bars vs. the frontal area lost in your body?

bonus points if you can determine what % of bluff body becomes streamlined body with the undermount change.

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Working off the other thread I replied to you on, just wait a few weeks and your problem will be solved. ;-)

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Jim Manton / ERO Sports

Thanks Jim - I'm excited to see what unfolds!

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

Hey Eric - that's a very good question! And one that prompted me to try and measure it. So I played around a bit yesterday using the "pixel count" method. I've never done that before so it was an interesting exercise. I basically took shots of 3 different setups, cut out the outline, filled it with red and then did a histogram count of the red pixels. I didn't convert it to m2 because I was just interested in the % difference between the setups. They are all quite close, with the least frontal area being high/narrow pads, then undermount/normal width (+2.17% more), then my current Aduro with normal width (+3.8% more). It goes to show that the narrow pad setup does make quite a difference to frontal area. There is also probably some measurement error since I haven't done this before. But still, an interesting exercise!

ENVE High/Narrow:



ENVE undermount/normal width:



Aduro current:

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Are you ready to do an Ultraman? | How I calculate Ironman race fueling | Strength Training for Athletes |

There's a chance the high/narrow could test really fast.

High, narrow. And block the rest of the area between the extensions with an undermount bottle. The amount of space left for air to flow, and the dirty edges make a great place to direct air around.

Tease. I thought you said this was gonna be announced the week of Kona? I busted my Felt Devox bar late this year and need to replace, but I'm having trouble finding a bar that will get me low enough. I got some time, tho.

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Proud Member of Chris McDonald's 2018 Big Sexy Race Team "That which doesn't kill me, will only make me stronger"
Blog-Twitter-Instagram-Race Reports - 2018 Races: IM Florida 70.3, IM Raleigh 70.3, IM 70.3 World Championships - South Africa, IM North Carolina 70.3

Funny you post this because I’m thinking of something similar. Want to get lower since I can’t go longer to get lower on my DA because of the fun Bayonet stem. So debating whether or not to get the Zipp undermount with the evo extensions or stick with my PD set up and just try to tuck and turtle more.

From what I’ve seen it seems like most clip on aerobars have the same/similar stack and would rather not drop $1k on a new set up aerobars but that might be what I have to do.

I’d be very interested to see the watt difference between the different positions too.

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What setup do you have? My experience with Felt's DA is that you can go as low and as long as you want. However, if you want something clean and fast then it will take some effort to track down what you need.

Now, I've set the bike up lower and longer with the double knuckle stem, but then that is not clean nor does it look fast. However, the below does. ;)

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My YouTubes

I have the flat stem on there with prosvet basebar and PD clips ons. Lower stack clip ons would work but can’t seem to find anything lower than the 46 mm the PD ones are.

Oh well. Don’t want to steal robs thread!

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