AeroGain Aero BTA system on the 3 mm carbon fibre mount plate with two bottles in carbon cages, front three-quarter view, white background
AeroGain Aero BTA bottles mounted between the extensions of a time-trial bike in a velodrome
AeroGain Aero BTA system with two bottles and a computer-mount arm on the carbon fibre mount plate
Aero BTA system
Scott Plasma triathlon bike against a red wall with AeroGain Aero BTA bottles mounted between the extensions
The three AeroGain BTA carbon fibre mount plates fanned side by side, three lengths
AeroGain Aero BTA double-bottle spacer on the 3 mm carbon fibre plate, front three-quarter view
AeroGain Aero BTA system with two bottles and the computer-mount arm extended, front three-quarter view on the carbon fibre plate
AeroGain BTA carbon fibre mount plate, 3 mm twill-weave carbon with slotted ends for the armrest bolts
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
AeroGain Aero BTA spacer parts laid out: nose-cone top with height spacers, cross-bolted spacer body with its bolts, and the 3 mm carbon fibre plate
AeroGain Aero BTA spacer on the 3 mm carbon fibre plate with the 10 mm height spacers fitted underneath, raising the nose-cone and arm
AeroGain Aero BTA spacer with height spacers fitted on the carbon fibre plate, side view
AeroGain Aero BTA system with two bottles and computer mount on the carbon fibre plate, angled view
AeroGain Aero BTA system with two bottles and computer mount on the carbon fibre plate, front three-quarter view from above
AeroGain BTA carbon fibre mount plate, short length, 3 mm carbon with slotted bolt ends
AeroGain BTA carbon fibre mount plate, long length, 3 mm carbon with slotted bolt ends
AeroGain Aero BTA system on the 3 mm carbon fibre mount plate with two bottles in carbon cages, front three-quarter view, white background
AeroGain Aero BTA bottles mounted between the extensions of a time-trial bike in a velodrome
AeroGain Aero BTA system with two bottles and a computer-mount arm on the carbon fibre mount plate
Aero BTA system
Scott Plasma triathlon bike against a red wall with AeroGain Aero BTA bottles mounted between the extensions
The three AeroGain BTA carbon fibre mount plates fanned side by side, three lengths
AeroGain Aero BTA double-bottle spacer on the 3 mm carbon fibre plate, front three-quarter view
AeroGain Aero BTA system with two bottles and the computer-mount arm extended, front three-quarter view on the carbon fibre plate
AeroGain BTA carbon fibre mount plate, 3 mm twill-weave carbon with slotted ends for the armrest bolts
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
AeroGain Aero BTA spacer parts laid out: nose-cone top with height spacers, cross-bolted spacer body with its bolts, and the 3 mm carbon fibre plate
AeroGain Aero BTA spacer on the 3 mm carbon fibre plate with the 10 mm height spacers fitted underneath, raising the nose-cone and arm
AeroGain Aero BTA spacer with height spacers fitted on the carbon fibre plate, side view
AeroGain Aero BTA system with two bottles and computer mount on the carbon fibre plate, angled view
AeroGain Aero BTA system with two bottles and computer mount on the carbon fibre plate, front three-quarter view from above
AeroGain BTA carbon fibre mount plate, short length, 3 mm carbon with slotted bolt ends
AeroGain BTA carbon fibre mount plate, long length, 3 mm carbon with slotted bolt ends
AeroGain

Aero BTA system

Front-bottle hydration that fills the dead air between your arms. Now on a 3 mm carbon fibre plate.

  • Median 8 W vs. riding with no bottles, 45 km/h, n=35 — 14 W best
  • Median 14 W swing off two frame bottles
  • 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
  • Delivered with 20 mm height adjustability — two 10 mm height spacers in the box
  • Six spacer angles keep the bottle level; three plate widths fit most tri-bar cockpits
$198.00 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 to the BTA: stop paying 6 W, start collecting 8 W.

8 W

Median versus riding with no bottles at all, 35 athletes at 45 km/h. Best measured: 14 W.

3 mm

Carbon fibre mount plate, 3 mm thick. Stiff and durable.

Nobody questions where the bottle goes

You’ll spend hundreds on a helmet chasing single-digit watts, then clip a cage to the down tube because that is where cages go. Two 750 ml frame bottles cost an average of 7 W at 45 km/h in our own velodrome testing, and 12 W at worst.

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

AeroGain Aero BTA system with two bottles and the computer-mount arm extended, front three-quarter 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 Aero BTA double-bottle spacer on the 3 mm carbon fibre plate, front three-quarter view

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 Aero BTA bottles mounted between the extensions of a time-trial bike in a velodrome

03 — Why the down tube does the opposite

The down tube already carries clean air between your legs. A bottle there makes an obstruction instead of filling one: an average of 7 W for two at 45 km/h.

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.

Aero BTA system

Front-bottle mount that sits in the gap between arms and chest, where the air is already stalling. 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. 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, two 10 mm height spacers, bolts and nuts. Matte black spacer, carbon-weave plate. Takes one or two bottles, and mounts under your existing armrest pads or full-length extensions with standard allen keys. Cages, bottles and the computer mount are sold 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 Aero BTA spacer parts laid out: nose-cone top with height spacers, cross-bolted spacer body with its bolts, and the 3 mm carbon fibre plate

03 — Modular spacer system

Six spacer angles from 0° to 30° keep the bottle horizontal at any extension angle, and two 10 mm height spacers in the box give you 20 mm of height adjustment. Most one-piece mounts don’t adjust at all.

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

04 — 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 Aero BTA system with two bottles and computer mount on the carbon fibre plate, front three-quarter view from above

05 — Integrated nose-cone

Leads airflow into the arm-chest gap instead of a blunt bottle face. Measurably less drag than our earlier design.

Take two measurements before you order

Your extension angle and your armpad bridge width. Get both right and the bottle sits 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
Tools and install

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

From the box to the bike in five steps

Steps 1 to 3 on the bench, 4 and 5 on a Specialized S-Works Shiv TT. The sequence is the same on any cockpit with a pad bridge. Standard hex keys, plus a torque wrench for the pad bolts.

010:11

Through-bolt the spacer

The bolt runs straight through the spacer body and into the top part on the far side. That is what holds the block together. Spacer height adjusts over 20 mm with different bolt lengths and extra spacers.

020:11

Carbon plate on

Two bolts, two washers, through the 3 mm carbon plate into the spacer and up into recessed nuts. That is what makes the joint so strong.

030:09

Cages on

Any standard two-bolt cage. Top cage first, with a long bolt all the way into the main spacer for extra transverse strength.

040:04

Onto the cockpit

The assembled unit drops onto the pad bridge, plate under the armcups. No extra brackets.

050:15

Bolted down

Your existing armcup bolts clamp the plate. Torque to your cockpit's spec, and you are done.

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, filling the arm-chest gap. Properly mounted, and velodrome-tested. Since October 2026: a 3 mm carbon plate and a cross-bolted spacer underneath.

Built for tri-bar cockpits and riders who measure things

This is for you if

  • A TT or triathlon bike with a tri-bar cockpit — pad bridge or full-length extensions.
  • You think in watts, not vibes.
  • Helmet and wheels sorted. You want the next real gain.
  • You want the mount to match your position, not the reverse.

This isn’t for you if

  • A road bike with no clip-ons and no pad bridge.
  • Two front bottles with fore-aft adjustment — see the Double Bottle BTA system V2.
  • Rear hydration and storage — that’s the Aero BTS PRO.
  • You don’t care about angle-matching.

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

Fit and installation, answered

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.

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.

Yes, if the clip-ons have a pad bridge to clamp onto. Not for road bikes without them.

Yes. For fore-aft adjustment on the second bottle, see the Double Bottle BTA system V2.

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.

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. Not a single-rider tunnel run and not CFD. Median 8 W, best 14 W. Two frame bottles cost a median of 6 W, so switching is worth a median of 14 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. Aero BTA median 8 W, 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; a double with the top bottle further back, 7.3 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 v2 carbon plate and cross-bolted spacer do not change the shape in the airflow. Test conditions available on request.

AeroGain Aero BTA system with two bottles and a computer-mount arm on the carbon fibre mount plate

Velodrome-tested in Denmark

Stop losing watts to a bottle you never measured

Median 8 W versus riding with no bottles, 14 W at best — and a median 14 W swing if you are coming off two frame bottles. 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 Aero BTA system

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