Aero BTA System Landing Page

THE MECHANISM

It's Not the Bottle. It's the Gap It Fills.

01 — THE DEAD AIR

In an aggressive aero position, a pocket of separated, turbulent air sits in the gap between your forearms and your chest. This is dead air — flow that has already detached from the body and is stalling instead of moving cleanly past it. Aerodynamically, it is expensive.

02 — FILLING THE GAP

Place a bottle between the arms, close to and parallel with the chest, and it fills that exact gap. Air that would otherwise separate and stall is instead guided smoothly around your whole body. The bottle stops being an obstruction and becomes part of the airflow.

Airflow schematic: frame-mounted disruption vs. between-the-arms flow attachment.

Why the Down Tube Does the Opposite

A bottle mounted on the down tube sits in a path of air that was already flowing cleanly between the legs. Putting a bottle there doesn't fill a gap — it creates a new obstruction where none existed. That's exactly why frame-mounted bottles add drag instead of removing it.

And because the bottle sits right in front of your chest, you can reach it without sitting up out of the aero position — no repeated loss of position to drink over the course of a race.

THE NUMBERS

Up to 12W Faster With Optimal Front-Bottle Placement vs. Conventional Setups

*AeroGain velodrome testing, Ballerup Super Arena, Denmark. 45 km/h, 0° yaw, n=32 athletes.

12W

peak saving observed, optimal setup

median saving across all 32 test athletes — the honest number, not the best-case one

>10W

added drag from two frame-mounted bottles, same 45 km/h test conditions

This isn't a single-rider wind-tunnel run. It's a population test across 32 athletes spanning a range of positions and body types — which is exactly why we lead with the range and not just the ceiling. Leading with the 12W best case alone would be no different from any other marketing claim; the honest spread is what makes it real. The gain runs from neutral all the way to roughly 12W depending on your position and setup, with 6W as the median outcome most riders should expect.

HOW THIS STARTED

This Started as a Bottle Stuffed Down a Race Suit

We didn't just theorise this. The aero gain was discovered by accident, used at the highest level of the sport, then banned — and the Aero BTA system is the engineered, legal successor to a technique that already proved itself.

2022

AeroGain founder Kristoffer Visti first experimented with carrying a bottle stuffed down the front of his race suit at the Danish National Championships, discovering the aero benefit by accident — not from a wind tunnel, from racing.

Later That Year

Triathlete Magnus Ditlev used the same technique at the Ironman World Championship in Kona — the same principle, now on the world's biggest triathlon stage.

Early 2024

World Triathlon and Ironman banned the in-suit technique, for safety and uniformity reasons — the aerodynamic principle wasn't in question, the method of carrying it was.

The Successor

The Aero BTA system was developed as the engineered, legal answer — same aerodynamic principle, filling the gap between the arms and chest, now properly mounted instead of stuffed into a suit.

What was once a rule-bending hack is now a properly engineered, velodrome-tested mount.

THE PRODUCT

The Aero BTA System

A front-mounted, between-the-arms hydration mount that fills the gap conventional bottle placement leaves open — engineered and velodrome-tested, not guessed at.

€169,90

Single or dual-bottle setups on the same mount

BTA Plate Width

Moyen (52 à 148 mm) Large (148 à 198 mm) Extra large (plus de 198 mm)

Angle

0° 10° 15° 20° 25° 30°

Express Worldwide Shipping via FedEx — Delivered in 1-5 days

30-Day Satisfaction Guarantee

Shop the Aero BTA System — €169.90

Complete Your Setup

Support d'ordinateur AeroGain BTA - grande hauteur

€44,90

+ Add Computer Mount

2 cages Tririg Kappa (haut et bas)

€159,90

+ Add Bottle Cages

HOW IT'S BUILT

Built to Sit Exactly Where the Gap Is

Modular Spacer System

Angle-matched spacers at 0°, 10°, 15°, 20°, 25° and 30°.

The bottle sits perfectly horizontal regardless of your extension angle — most one-piece BTA mounts don't adjust at all, so the bottle sits tilted to whatever angle your bars happen to be at.

Three Width Fits

Medium (52–148mm pad-bridge width), Wide (148–198mm), Extra Wide (above 198mm).

Covers most tri-bar setups without custom fabrication or filing down parts to fit.

Integrated Nose-Cone

A shaped nose-cone leads the airflow into the arm-chest gap instead of presenting a blunt bottle face to it.

Measurably less drag than AeroGain's earlier, non-nose-cone BTA design.

Clamps to Standard Pad Bridges and Aero Bars

Mounts directly onto standard pad bridges and tri-bar systems, matte black finish.

Fits most existing tri-bar cockpits without swapping hardware.

Made and Tested in Denmark

Small-batch manufacturing, validated on a velodrome with a 32-athlete population test — not CFD-only or single-rider marketing claims.

Numbers you can trust because they weren't generated in a spreadsheet.

Single or Dual-Bottle Setups

The mount accepts one or two bottles on the same frame.

Race-day hydration without going back to a frame-mounted bottle for the second bottle.

How to measure your cockpit for the right fit

Measure your pad-bridge width and extension angle before ordering — see the size guide.

How to mount the Aero BTA system

Tool-free reference — standard allen keys, a few minutes, no special tools.

IS THIS FOR YOU

Built for Tri-Bar Cockpits and Riders Who Measure Things

This is for you if:

You race on a dedicated TT or triathlon bike with a tri-bar cockpit and pad bridge

You already know your FTP and think in watts, not vibes

You've optimised your helmet and wheels and want the next real gain, not a marginal-gains platitude

You want a mount that adjusts to your actual extension angle instead of forcing your position to match the mount

This isn't for you if:

You ride a road bike without clip-on aero bars or a pad bridge to clamp onto

You're looking for a rear/behind-the-saddle hydration and storage system (that's a different AeroGain product, the BTS system — not this one)

You want a one-piece mount and don't care about angle-matching

If your cockpit has a pad bridge and you care about the number, this is built for exactly that setup.

COMMON QUESTIONS

Fit and Installation, Answered

The Aero BTA system clamps onto standard pad bridges and tri-bar systems, in three width fits: Medium (52–148mm pad-bridge width), Wide (148–198mm), and Extra Wide (above 198mm). Measure your pad-bridge width before ordering — see the sizing schematic above.

Yes, as long as your clip-on aero bars have a pad bridge to clamp onto, the same width and angle fits apply. It's not designed for road bikes without clip-ons.

Yes, the mount supports single or dual-bottle setups on the same frame.

The system ships with angle-matched spacers at 0°, 10°, 15°, 20°, 25°, and 30°, so you pick the spacer that matches your extension angle and the bottle sits perfectly horizontal regardless of your position.

No. It installs with standard allen keys in a few minutes — no special tools required.

AeroGain's own velodrome testing at Ballerup Super Arena, Denmark, at 45 km/h, 0° yaw, across 32 athletes — not a single-rider tunnel run or a CFD simulation. Median saving was 6W, with a range up to 12W depending on rider position and setup.

TEST DATA

The Numbers

The real aerodynamic drag data behind the BTA system's savings claim — measured across a realistic race speed range, not modeled. Every figure below is a wind-tunnel and velodrome observation, presented as-is.

6–10W

Drag cost of two 750ml bottles mounted on the frame, versus running no bottles at all.

15W

Most extreme frame-bottle penalty observed in testing — recorded at 45 km/h.

5–12W

Additional savings from relocating those same two bottles to a between-the-arms (BTA) mount.

20W+

Total potential savings when moving two bottles from the frame to BTA — the combined, real-world upside.

All figures observed across a realistic race speed range. Individual results vary with rider position, bottle size, and yaw.

Test Conditions & Methodology

Aerodynamic claims are based on AeroGain in-house testing conducted at Ballerup Super Arena velodrome, Denmark. Conditions: 45 km/h, 0° yaw, n=32 athletes across a range of riding positions and body types. Savings shown compare optimal front-bottle (Aero BTA) placement against a baseline of no BTA mount / conventional setup (no front bottle, or a frame-mounted bottle). Results ranged from neutral to approximately 12W, with a median saving of 6W across the test population. The >10W figure for frame-mounted bottles reflects two bottles mounted on the frame under the same test conditions. Individual results vary by rider position, equipment, and setup.

YOUR FRAME-MOUNTED BOTTLE IS COSTING YOU OVER 10W

Nobody Questions Where the Bottle Goes