AeroGain Double Bottle BTA system with an XLAB Torpedo on top and a bottle below, on the 3 mm carbon fibre plate
Rider standing with a Specialized S-Works TT bike on a country road, an AeroGain BTA bottle mounted between the extensions
AeroGain Double Bottle BTA system with two bottles in carbon cages, top bottle forward, on the 3 mm carbon fibre plate
AeroGain Double Bottle BTA system carrying a single bottle on the top section, on the carbon fibre plate
AeroGain Double Bottle BTA system with two bottles, angled side view on the carbon fibre plate
AeroGain Double Bottle BTA system with XLAB Torpedo and bottle, angled view
AeroGain Double Bottle BTA system with the top bottle forward and a second bottle below
AeroGain Double Bottle BTA top section with one bottle mounted, carbon fibre plate below
AeroGain Double Bottle BTA top section with one bottle, three-quarter view
AeroGain Double Bottle BTA system with an empty bottle cage on the top section
AeroGain Double Bottle BTA spacer and top section on the 3 mm carbon fibre plate, no bottles
AeroGain Double Bottle BTA system with an XLAB Torpedo on top and a bottle below, on the 3 mm carbon fibre plate
Rider standing with a Specialized S-Works TT bike on a country road, an AeroGain BTA bottle mounted between the extensions
AeroGain Double Bottle BTA system with two bottles in carbon cages, top bottle forward, on the 3 mm carbon fibre plate
AeroGain Double Bottle BTA system carrying a single bottle on the top section, on the carbon fibre plate
AeroGain Double Bottle BTA system with two bottles, angled side view on the carbon fibre plate
AeroGain Double Bottle BTA system with XLAB Torpedo and bottle, angled view
AeroGain Double Bottle BTA system with the top bottle forward and a second bottle below
AeroGain Double Bottle BTA top section with one bottle mounted, carbon fibre plate below
AeroGain Double Bottle BTA top section with one bottle, three-quarter view
AeroGain Double Bottle BTA system with an empty bottle cage on the top section
AeroGain Double Bottle BTA spacer and top section on the 3 mm carbon fibre plate, no bottles
AeroGain

Double Bottle BTA system

Our most versatile BTA system. One bottle or two, an XLAB Torpedo, top bottle forward or further back — now on a 3 mm carbon fibre plate.

  • Single, double or Torpedo: one bottle, two bottles, or an integrated XLAB Torpedo with a bottle below, on the same mount
  • Choose the placement: top bottle forward between the arms (median 8 W) or further back towards the chest (median 7.3 W), vs. riding with no bottles, 45 km/h, n=35 — 14 W best
  • New: 3 mm carbon fibre plate — adds almost nothing to your stack, barely flexes, mounts under armcups or full-length extensions
  • New: cross-bolted spacer — bolts run right through the body and are held by nuts, so it needs less material and is lighter
  • Delivered with 20 mm height adjustability — two 10 mm height spacers in the box
  • Six spacer angles, three plate widths — or the Fit kit with 10°, 15° and 20° to test on the bike
$199.00 USD
/
VAT not included. Import duties may apply on reception.
  • In stock, ready to ship
  • Backordered, shipping soon
  • Express worldwide shipping with FedEx — 2–4 working days
  • 30-day returns
  • 2-year warranty
  • Crash replacement

Pairs well with

The numbers — velodrome-tested, not marketed

14 W

Median swing from two frame bottles into the cockpit: stop paying 6 W, start collecting 8 W.

8 W

Median for the double-bottle BTA versus no bottles, top bottle forward. Best measured 14 W; 7.3 W with it further back.

3 setups

Single bottle, two bottles, or an XLAB Torpedo with a bottle below. Same mount.

Two bottles, and nobody asks where they go

A full-distance bike leg needs more fluid than one bottle carries, so the second goes on the down tube. Two 750 ml frame bottles cost an average of 7 W at 45 km/h in our own velodrome testing. Move both into the cockpit and the same test returns a median of 8 W.

It’s not the bottle. It’s the gap it fills.

AeroGain Double Bottle BTA system with two bottles, angled side view on the carbon fibre plate

01 — The dead air

A pocket of separated, stalling air sits between your forearms and your chest. Aerodynamically, that pocket is expensive.

AeroGain Double Bottle BTA system carrying a single bottle on the top section, on the carbon fibre plate

02 — Filling the gap

A bottle placed there fills it, so air is guided round your body instead of separating — and you can drink without leaving aero.

AeroGain Double Bottle BTA system with the top bottle forward and a second bottle below

03 — Carrying the second bottle up front

The redesigned top section keeps both bottles in the cockpit, so you get race-day volume without putting back the drag you just removed. A median of 8 W with the top bottle forward, 7.3 W with it further back.

The data

The whole test, not the flattering slice. 35 athletes, four bottle setups, one velodrome, measured at race speed.

Bar chart of power saved at 45 km/h versus riding with no bottles across four setups tested on 35 athletes at Ballerup Super Arena: two 750 ml bottles on the frame at minus 6 W median, single bottle between the arms at 4.5 W, double-bottle BTA at 8 W, and double-bottle BTA with the top bottle further back at 7.3 W
Power saved at 45 km/h versus riding with no bottles. Two 750 ml frame bottles cost a median of 6 W. A single bottle between the arms returns 4.5 W; a double-bottle BTA 8 W, and 7.3 W with the top bottle further back.
6 WTwo 750 ml frame bottles versus none. Average 7 W, worst 12 W.
8 WAero BTA versus no bottles. Best measured 14 W.
14 WFrame bottles to Aero BTA: stop paying 6 W, start collecting 8 W.
26 WWorst frame position plus best BTA result. The ceiling, not the expectation.
  • 35 athletes, Ballerup Super Arena velodrome, Copenhagen.
  • Test speeds 35–50 km/h, reported at 45 km/h.
  • Baseline CdA 0.165–0.237.
  • Medians: −6 W, 4.5 W, 8.0 W and 7.3 W, in the order shown.
  • Two frame bottles: average 7 W, median 6 W, worst measured 12 W.
  • Best measured Aero BTA result 14 W. Not all riders tested every setup.
  • Bars are group averages; whiskers the spread. Results vary with rider.

Double Bottle BTA system

Our most versatile BTA system. One bottle, two bottles, or an XLAB Torpedo with a bottle below, and the top bottle forward between the arms or further back towards the chest. Same tested shape, now on a 3 mm carbon fibre plate with a cross-bolted spacer.

What's new
The base plate is carbon fibre, 3 mm thick: lower stack under your pads than the previous plate, and stiff enough that it barely flexes under load. It now mounts under full-length extensions as well as under armcups. The spacer is cross-bolted — bolts run through the body and are held by nuts, so the whole block is clamped together and needs less material. Built for the roughest roads.

What you choose
Plate width — Medium 52–148 mm, Wide 148–198 mm, Extra Wide 198–238 mm. Spacer angle — 0°, 10°, 15°, 20°, 25°, 30°, matched to your extensions, or the Fit kit with 10°, 15° and 20° to test on the bike.

In the box
Carbon fibre base plate, cross-bolted spacer, top section, two 10 mm height spacers, bolts and nuts. XLAB Torpedo compatible. Cages, bottles and the Torpedo are purchased separately.

The shape stayed. Everything under it changed.

AeroGain BTA carbon fibre mount plate, 3 mm twill-weave carbon with slotted ends for the armrest bolts

01 — 3 mm carbon fibre plate

New. A flat carbon fibre plate, 3 mm thick, replaces the previous base plate. Lower stack under your pads, and stiff enough that it barely flexes when you load it.

Exploded view of the AeroGain Aero BTA spacer: the transverse bolt running through the spacer body, with the two 10 mm height spacers between top and base

02 — Cross-bolted spacer

New. Bolts run transversely through the spacer body and are held by nuts, so the whole block is clamped together. Because the bolts carry the load, the spacer needs less material and is lighter. Built for the roughest roads.

AeroGain Double Bottle BTA system with XLAB Torpedo and bottle, angled view

03 — Three setups, one mount

One bottle, two bottles, or an XLAB Torpedo with a bottle below. The top bottle sits forward between the arms for maximum aero, or further back towards the chest.

AeroGain Double Bottle BTA top section with one bottle mounted, carbon fibre plate below

04 — Modular spacer system

Six spacer angles from 0° to 30° keep both bottles horizontal at any extension angle, and two 10 mm height spacers in the box give you 20 mm of height adjustment.

The three AeroGain BTA carbon fibre mount plates fanned side by side, three lengths

05 — Three width fits

Medium 52–148 mm, Wide 148–198 mm, Extra Wide above 198 mm — now all cut in carbon. No filing parts down to fit.

AeroGain Double Bottle BTA system with an empty bottle cage on the top section

06 — Works with your hydration system

Clamps to standard pad bridges and is compatible with the XLAB Torpedo. Your existing armcups do the clamping.

Take two measurements before you order

Your extension angle and your armpad bridge width. Get both right and the bottles sit horizontal and centred.

1

Match your spacer to your extension angle

Match the spacer to the upward tilt of the whole assembly — mounting bracket and extensions together, not just the extension. Extensions level (0°) → the 0° spacer; tilted 20° → the 20° spacer; 30° → the 30° spacer.

Not sure? Rest your phone’s level app flat on your extensions to read the angle, or pick the Fit kit in the angle menu: three spacers, 10°, 15° and 20°, so you can test and keep the one that fits.

Technical line drawings of an AeroGain BTA mount carrying two bottles at 0, 20 and 30 degree extension angles, showing how a spacer matched to the extension angle keeps the bottles horizontal
Left: the assembly on the bike. Right: the matching spacer wedge. At 20° and 30° it cancels the tilt so the bottles stay horizontal.
2

Measure your armpad bridge width

Bolt centre to bolt centre, straight across: Medium 52–148 mm, Wide 148–198 mm, Extra Wide 198–238 mm.

Technical line drawing of a triathlon cockpit seen from above, with arrows marking the bolt-to-bolt distance across the armpad bridge that determines which AeroGain BTA mount plate size to order
Measure between the centres of the two mounting bolts. That one dimension decides your plate size.
How it mounts

Sandwiched under your armcups — or under full-length extensions — which clamp it in place. At 3 mm the carbon plate adds almost nothing to your stack. No extra brackets, and no swapping your pads.

Plate width chart
FitBolt-to-bolt pad-bridge width
Medium52–148 mm
Wide148–198 mm
Extra Wide198–238 mm
What’s in the box

Carbon fibre base plate, cross-bolted spacer, top section, two 10 mm height spacers, bolts and nuts. Cages and bottles separate; XLAB Torpedo compatible.

Tools and install

Standard allen keys, a few minutes. Choose your plate width and spacer angle above before ordering.

This started as a bottle stuffed down a race suit

Found in testing, raced at the highest level, then banned. This is the legal successor.

2022

Founder Kristoffer Visti found the gain through extensive testing: a lunch box down the front of his race suit. He raced it at the Danish half-distance championships and set the fastest bike split.

Later that year

Magnus Ditlev used the same technique at the Ironman World Championship in Kona.

Early 2024

World Triathlon and Ironman banned it — for safety and uniformity, not aerodynamics.

The successor

Same principle, properly mounted, with both race bottles in the cockpit and none on the frame. Since October 2026: a 3 mm carbon plate and a cross-bolted spacer underneath.

Built for long-course riders who don’t want a frame bottle

This is for you if

  • One bottle isn’t enough, and you don’t want the second on the down tube.
  • A TT or triathlon bike with a tri-bar cockpit — pad bridge or full-length extensions.
  • You want to fine-tune fore-aft bottle position, not accept one fixed spot.
  • You run an XLAB Torpedo or similar and want it to fit.

This isn’t for you if

  • A road bike with no clip-ons and no pad bridge.
  • You only ever run one bottle up front — that’s the Aero BTA system.
  • Rear hydration and storage — that’s the Aero BTS PRO.
  • You don’t care about angle-matching.

Pad bridge, two bottles, and you care about the number? Built for that.

Fit and installation, answered

It’s our most versatile BTA system: one bottle, two, or an XLAB Torpedo. The top bottle sits forward between the arms or further back towards the chest, and the mount takes one or two bottles. Our 35-athlete test measured both: 8 W median versus no bottles with it forward, 7.3 W further back, against 4.5 W for a single bottle. Choose the Aero BTA system if you only ever run one.

Two things. The base plate is now carbon fibre, 3 mm thick: lower stack under your pads, minimal flex, and it mounts under full-length extensions as well as armcups. The spacer is now cross-bolted — bolts run through the body and are held by nuts. Built for rough roads. The shape in the airflow is unchanged, so the velodrome numbers above still apply.

Yes — that’s new. The 3 mm carbon plate is thin and stiff enough to sit under full-length extensions, not only under armcups. The previous plate was for armcups only.

Three plate widths: Medium 52–148 mm, Wide 148–198 mm, Extra Wide above 198 mm. Measure bolt-to-bolt across your pad bridge — the chart is in the setup guide above. The plate mounts under armcups or under full-length extensions.

Yes. Bottle cages and bottles are purchased separately.

Yes. One or two bottles on the same mount, so you can add the second for long course without changing hardware.

That’s what the spacers are for — 0° to 30° in six steps, matched to your whole extension assembly. Not sure which? Pick the Fit kit in the angle menu and you get three spacers, 10°, 15° and 20°, to test on the bike.

Carbon fibre base plate, cross-bolted spacer, top section, two 10 mm height spacers, bolts and nuts. Cages, bottles and the Torpedo are purchased separately.

No. Standard allen keys, a few minutes. The plate goes under your existing pads or full-length extensions.

Our own velodrome testing at Ballerup Super Arena, Copenhagen: 35 athletes, 35–50 km/h, reported at 45 km/h versus riding with no bottles. Median 8 W with the top bottle forward, 7.3 W further back; best 14 W. Two frame bottles cost a median of 6 W.

30-day satisfaction guarantee on unused units in original condition and packaging. Confirm your pad-bridge width and extension angle first.

All aero figures from AeroGain in-house velodrome testing at Ballerup Super Arena, Copenhagen: 35 athletes, test speeds 35–50 km/h, baseline CdA 0.165–0.237, reported as power saved at 45 km/h versus riding with no bottles at all. The double-bottle BTA median is 8 W with the top bottle forward between the arms and 7.3 W with it further back; best measured 14 W. Two 750 ml frame bottles cost an average of 7 W, a median of 6 W, worst measured 12 W — so switching is worth a median of 14 W, an average of 15 W, and 26 W in the best measured case. A single bottle between the arms returns a median of 4.5 W. Not all riders tested every setup. Individual results vary with rider position, bottle size and yaw. The test was run on the previous base plate; the carbon plate and cross-bolted spacer do not change the shape in the airflow. Test conditions available on request.

AeroGain Double Bottle BTA system with two bottles in carbon cages, top bottle forward, on the 3 mm carbon fibre plate

Velodrome-tested in Denmark

One mount. Every setup you’ll race.

Median 8 W versus riding with no bottles, 14 W at best — and a median 14 W swing off two frame bottles. One or two bottles or an XLAB Torpedo, six spacer angles, three plate widths — now on a 3 mm carbon plate.

Made and tested in Denmark · Express FedEx · 30-day satisfaction guarantee

Shop the Double Bottle BTA system

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