Aero BTS PRO system

Name: Aero BTS PRO system
Brand: AeroGain
Price: 2659.9 DKK
Availability: InStock

Behind-the-saddle hydration and storage, reviewed and approved by World Triathlon and Ironman.

1–4 W faster than two bottles close together behind the saddle — fastest of six setups, n=25
900 ml sealed storage — 100 ml more than the standard BTS
Shell hugs the bottles: less exposed surface, smaller wake
Saddle-specific carbon-tube build, ~350 g, 2 × 1000 ml bottles
White logo, matched to the Aero Cockpit

2.659,90 DKK

inkl. moms.

Free EU shipping over 200 EUR

30-day returns

2-year warranty

Crash replacement

In stock, ready to ship
Backordered, shipping soon

Levering 1-3 hverdage
30 dages returret
2 års garanti
Erstatning ved styrt

Pairs well with

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25 athletes. Six bottle setups. One velodrome. Every run published.

Two bottles behind your saddle, in the fastest of the six positions we measured — spares kit included.

Median 5.3 W saved at 45 km/h versus riding with no bottles at all, and 14 W for the best-matched rider. 2 × 1000 ml plus 900 ml of sealed storage, moulded to your exact saddle.¹

5.3 W median · 14 W bestvs. no bottles, n=25, 45 km/h
900 ml sealedtube, CO2, lever, multitool
~350 gsaddle-specific carbon build
15 saddle fitsround and oval rails

30-day returns · 2-year warranty · Crash replacement

Choose your saddle Not ready? Read the 8-chapter aero report first →

1. AeroGain velodrome testing, Ballerup Super Arena. Full method and per-rider spread below.

In the press & officially approved

Pro Tri News

“AeroGain’s BTS Unit Is Now Legal Everywhere”

11 June 2026 · Read the article →

Formal technical approval, in writing

Approved by the technical committee, then upheld by the Danish referees and the head referee for Ironman EMEA. Read the statement →

Officials pulled the unit the night before Ironman Texas, where Vincent Luis and Matthias Pedersen debuted it. It is now approved under World Triathlon rules. The same unit, unchanged.

Pro Tri News and World Triathlon are trademarks of their respective owners, shown to identify published coverage and a published technical ruling. Neither implies sponsorship or endorsement of AeroGain.

The numbers — velodrome-tested

14 W

Best measured result versus riding with no bottles at all. Median across 25 athletes: 5.3 W.

80 mm

Fore-aft bottle adjustment, from the saddle-specific carbon-reinforced clamp.

6 min

Average install. One standard 4 mm allen key, no proprietary tools.

You already bought the fast wheels. The bottles are where the watts went back.

Deep sections. A fit session. A skinsuit. A helmet chosen off a YouTube comparison. Then, two days out, you tape an inner tube to the top tube and wedge a bottle in the frame cage.

Twenty minutes of decisions undoing a season of them.

Behind the saddle is genuinely fast: it fills the low-pressure pocket your back leaves behind. But where decides how much. One bottle slung below the saddle was slower than carrying nothing — a median of 1 W slower. Two close together, the pro-field default, returned 3.3 W. The wide V returned 5.3 W.

Same bottles, same rider, same speed. Six watts of spread, all geometry.

Built around three marginal gains

01 — Wide V-formation

Competitors sit the bottles close together and parallel. The V opens that spacing so they fill more of your wake instead of leaving its outer edges empty — a median of 5.3 W versus riding with no bottles at all, and 14 W for the best-measured rider.

02 — Saddle-specific fit

Moulded to your exact saddle model and reinforced around a carbon-fibre tube. Stiff and durable, even on rough roads and gravel.

03 — 900 ml of storage

The shell hugs both bottles, with 900 ml sealed under a close-fitting lid. Enough for a full spares kit — inner tube, CO2, lever, multitool.

The data

Months of testing, 25 athletes, a wide range of positions, race speeds and equipment.

Bar chart of power saved at 45 km/h versus no bottles across five behind-the-saddle setups, 25 athletes at Ballerup Super Arena: one bottle below saddle 1 W slower, one bottle horizontal high behind saddle 2 W, two bottles close together mounted high 3.3 W, Aero BTS 5 W, Aero BTS PRO 5.3 W median — Median power saved at 45 km/h versus no bottles: **1 W slower** for one bottle below the saddle, **2 W** for one high behind it, **3.3 W** for two close together (the pro-field default), **5 W** Aero BTS, **5.3 W** Aero BTS PRO. Error bars show one standard deviation.

Per-athlete bar chart of power saved at 45 km/h versus no bottle for all 25 riders tested, comparing one bottle below saddle, one bottle horizontal high behind saddle, two bottles close together mounted high, Aero BTS and Aero BTS PRO — The same test, rider by rider. For a few riders a competing setup won; the best-matched rider gained 14 W. Across the group, the PRO and the Aero BTS finish on top.

25 athletes, Ballerup Super Arena velodrome, Copenhagen.
Test speeds 35–50 km/h, normalised to watts at 45 km/h.
TT bikes, aero position, race suit.
Baseline CdA 0.165–0.237.
Every setup on 1000 ml bottles, each rear system as close to the rider’s back as possible.
Not all riders tested all six setups.

Want the reasoning, not the product?

Where aero minutes are actually lost, why the arms are the front fairing, and how to audit your own bike. Free, no discount code.

How the PRO differs from the standard BTS

Same wide V and same saddle clamp. The PRO shell hugs the bottles more closely, reducing exposed surface between them and tightening the wake profile, and carries 100 ml more storage. Across our testing it was the fastest of the six setups measured (n=25 athletes, 45 km/h, 0° yaw).

The white logo

Ships with a white AeroGain logo, matched to the Aero Cockpit’s white colourway.

Fifteen saddle fits

Wove V8, Gebiomized Stride, Prologo T Galle TT, Prologo Dimension CPC Nack 143 (carbon rails), Prologo Dimensions CPC Tirox 143 (alu rails), ISM PN3.1, ISM PN4.0, Specialized Sitero, Dash Integrated seat post, Selle Italia Watt Superflow, Selle Italia Watt Superflow 3D Carbon, Fizik Transiro Aeris, PRO Stealth Team, PRO Aerofuel and Bontrager Hilo Pro. The next saddles are decided by community poll on Instagram.

Aero numbers from AeroGain in-house velodrome population testing at Ballerup Super Arena, Copenhagen, n=25 athletes, test speeds 35–50 km/h normalised to 45 km/h, 0° yaw.

Installation & compatibility

Simple to install, built to fit. One standard 4 mm allen wrench.

Saddle compatibility

Round and oval rails, verified across 15 saddle models — pick yours from the dropdown above.

Each clamp is made for one saddle, built around a carbon-fibre tube for stiffness at low weight.

Installation time

Under 6 minutes, box to bike. No special tools.

What’s included

Carbon BTS saddle clamp, mounting hardware and an install guide. Add a cage and your two 1000 ml bottles.

Whether this is actually for you

Each unit is built to one saddle model, so a mismatch costs us both time.

Buy it if

You hold an aero position for an hour or more at a time.
Your saddle is one of the 15 in the dropdown — or you’ll ask us first.
Two bottles and a spares kit, and nowhere sensible to put them.
You’d rather see 25 riders’ raw data, losing runs included, than one number.
You race under World Triathlon or Ironman rules.

Don't buy it if

You just want to carry the bottles. A traditional mount does that for less.
Your saddle isn’t listed and you’d rather not email us.
You want a guaranteed number. Our chart shows athletes for whom a rival layout won.
You want front-of-bike hydration. That is the BTA hydration system.

Kristian Høgenhaug racing Challenge Roth 2026 on a Quintana Roo TT bike with the AeroGain Aero BTS PRO and two bottles mounted behind the saddle

Athlete spotlight

Ridden by Kristian Høgenhaug

8th place, Challenge Roth 2026.

Shop the BTS PRO

Engineered on the velodrome

Design engineer Carl and founder Kristoffer break down the BTS system during velodrome testing.

What happens if it isn’t right

A saddle-specific part carries real fit risk. Here is who absorbs it.

Ask before you order

Not on the list? One email before you order, and we’ll confirm compatibility.

30 days to change your mind

Full refund within 30 days. If the fit is wrong, we’ll exchange or return it.

2-year warranty

Two years against manufacturing and material defects.

Crash replacement

Replaced at a reduced price, not full retail. Send photos and your order number.

Choose your saddle

What riders who bought it say

Great product (BTS Pro System)

“The product I bought was great! It was shipped pretty fast and fits great behind the saddle together with a solid saddle mount. The small lid came off, but I got in contact with them and got a new one as replacement.”

AlbertSweden · Aero BTS PRO system

Easy to install, robust, raced

“The product was easy to install, robust, and tested at Ironman Tours and Eastbourne middle distance. The service from the team has been superb and fast. I highly recommend ordering from them, at least for a front hydration system.”

OliUnited Kingdom · Aero BTS PRO, Aero Cockpit and BTA system

And on the rest of the range

“Super quick service and shipping. High degree of having the cockpit in a perfect aero fit with functional systems.”

Beat WeinmannSwitzerland · BTA system and spacers

“Great product. Simple and well made. Fits well with Speedmax CF8 — thanks to the offset it is compatible with the Canyon front hydration system (enough space to fill it in) and bento box.”

PawelPoland · BTA system, offset spacer

“Well constructed with more than enough adjustment. Light and sturdy. Arrived quickly.”

Christian RamosPortugal · High-sided and dual-sided armrests

“Top service and communication.”

DietmarService

Reviews collected by AeroGain from verified customers. Product attribution checked against order records. Reviews about other products in the range are shown as such and are not presented as reviews of the Aero BTS PRO.

Questions, answered

Because no system is fastest for everyone, and any brand can go looking for the riders it suits. We publish all 25 athletes without picking results — including the riders for whom a rival layout won.

Median saved at 45 km/h versus no bottles: 5.3 W BTS PRO, 5 W BTS, 3.3 W two bottles close together, 2 W one bottle high behind the saddle, −1 W one below it. Every setup on 1000 ml bottles, each rear system as close to the rider’s back as possible.

Fifteen saddle-specific moulds with no universal part to amortise, a carbon-reinforced structure that keeps the V from drifting under load, and population testing on 25 athletes rather than one rider and a render.

Against the layout most riders already use, the median gain is roughly 2 W — about a minute over an Ironman bike leg. If that minute doesn’t matter this season, spend the money elsewhere.

Different problems, and the fastest setups run both. The BTS PRO carries the two bottles and the spares kit behind you; the BTA hydration system handles the bottle you drink from, between the arms — a median of 8 W versus no bottles (n=35).

Buying one first: front bottle if you are on a frame cage, this if your problem is two bottles and nowhere for your tube and CO2.

Yes. Banned at launch at Ironman Texas, since officially approved by World Triathlon and accepted by Ironman. Already raced by hundreds of pro and age-group athletes.

Fit is set by your saddle, not your frame. Pick from the 15 models in the dropdown above — including Wove V8, Prologo T Galle TT, ISM PN3.1, Specialized Sitero and PRO Stealth Team.

Across 25 athletes, a median of 5.3 W at 45 km/h versus riding with no bottles at all, and 14 W best measured. Against two bottles mounted close together behind the saddle, roughly 2 W. The per-rider chart above shows the real spread.

Round and oval, on universal hardware, with clamp geometry matched to your saddle model. If yours isn’t listed, contact us before ordering and we’ll confirm compatibility.

Two years against manufacturing and material defects.

FedEx Express, dispatched from our EU warehouse within 1–2 business days. Typically 1–3 business days within the EU and 2–4 internationally, tracked end to end.

Yes, 30 days for a full refund. Because each build is saddle-specific, confirm your saddle model before ordering — but if it still isn’t right, we’ll help you exchange or return it.

All aero figures from AeroGain in-house velodrome testing at Ballerup Super Arena, Copenhagen: 25 athletes, test speeds 35–50 km/h normalised to watts at 45 km/h, TT bikes in aero position with race suit, baseline CdA 0.165–0.237. Every setup tested with 1000 ml bottles, each behind-the-saddle system positioned as close as possible to the rider’s back. Baselines as stated. Test conditions available on request.

Limited production run

Stop leaving watts on the table

A median of 5.3 W at 45 km/h versus riding with no bottles, 14 W for the best-matched rider. Saddle-specific carbon at ~350 g, six minutes to fit. Reviewed and approved by World Triathlon and Ironman.

Free EU shipping · 30-day returns · 2-year warranty · Crash replacement

Choose your saddle

P.S.

Still reading and not buying is reasonable. It is a lot of money for a bottle mount.

Honest version: a median 5.3 W against no bottles, around 2 W against the layout you probably already run. Over 180 km, a minute or several. Real, and not enormous.

We will not pretend the number is bigger than it is, or hide the riders for whom a competitor won. The chart is above.

If the answer today is no, take the report. Chapter 7 on wake management will tell you more than this page will.

Send me the report →

Free report — no discount code, no sales call

8 Ways To Be More Aero

Cutting minutes off your bike split without adding a watt. The thinking that produced the Aero BTS PRO, written before we had anything to sell you.

Why “buying aero” so often fails
Where minutes are actually lost
Aerodynamics is a system, not a parts list
The arms are the front fairing
Hydration: why versatility beats integration
Arm support and position repeatability
Wake management — the chapter this product came from
A practical aero audit you can run yourself

By AeroGain’s founder, from velodrome work with 150+ athletes across Denmark and Europe. Physics, not opinion.