Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
Double Bottle BTA system
AeroGain

Double Bottle BTA system

Both race bottles in the cockpit instead of on the frame.

  • Median 8 W vs. riding with no bottles, 45 km/h, n=35 — 14 W best
  • Top bottle forward or further back: 8 W / 7.3 W
  • One or two bottles on the same mount
  • Six spacer angles, three plate widths
  • XLAB Torpedo compatible
€169,90 EUR
/
VAT included
  • Free EU shipping over 200 EUR
  • Express worldwide shipping via FedEx — 1–5 days
  • 30-day satisfaction guarantee
  • In stock, ready to ship
  • Backordered, shipping soon
  • Express worldwide shipping with FedEx — 1–4 business 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.

6 angles

Angle-matched spacers from 0° to 30°, so both bottles sit level whatever your extensions do.

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.

01 — The dead air

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

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.

03 — Carrying the second bottle up front

The redesigned V2 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 V2

Carries one or two bottles in the cockpit. The redesigned top section puts the top bottle forward between the arms, or further back towards the chest.

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.

In the box
One mounting plate, one angled spacer, one top piece and all bolts. Matte black, XLAB Torpedo compatible. Cages and bottles are purchased separately.

Built to sit exactly where the gap is

01 — Redesigned top section

The top bottle sits forward between the arms for maximum aero, or further back towards the chest. One bottle or two on the same mount.

02 — Modular spacer system

Six spacer angles from 0° to 30° keep both bottles horizontal at any extension angle.

03 — Three width fits

Medium 52–148 mm, Wide 148–198 mm, Extra Wide above 198 mm. No filing parts down to fit.

04 — Works with your hydration system

Clamps to standard pad bridges, matte black, and 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.

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, which clamp it in place. 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

One mounting plate, one angled spacer, one top piece and all bolts. 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

Discovered by accident, raced at the highest level, then banned. This is the legal successor.

2022

Founder Kristoffer Visti raced the Danish Nationals with a bottle down the front of his suit, and found the gain by accident.

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. V2 goes further: both race bottles in the cockpit, none on the frame.

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 and pad bridge.
  • 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

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.

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.

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.

One mounting plate, one angled spacer, one top piece and all bolts. Cages and bottles are purchased separately.

No. Standard allen keys, a few minutes. The plate goes under your existing pads.

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. Test conditions available on request.

Velodrome-tested in Denmark

Both bottles in the cockpit. None on the frame.

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, six spacer angles, three plate widths, XLAB Torpedo compatible.

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

Shop the Double Bottle BTA V2

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