Frame mounted bottles — an average of 7 W slower than riding with no bottles.
Two frame mounted bottles consistently measure slower than no bottles, with a median penalty of 6 W and 12 W in the worst case.
The total saving from moving two bottles from the frame to an Aero BTA system with two bottles, is a median of 14 W at 45 km/h — an average of 15 W, and 26 W for the best measured rider.
Front-bottle BTA hydration. A median of 8 W faster.
A BTA (between-the-arms) bottle isn't just somewhere to put your fluid. Get the position right and it becomes one of the cheapest watts you'll find on a triathlon bike — a smoother "fairing" in front of your chest, where the air is otherwise getting trapped between your arms and your chest. Done well, optimal front-bottle placement saves a median of 8 watts versus riding with no bottles at all.
That headline holds up in the velodrome. Across 35 athletes at 45 km/h, a correctly fitted AeroGain front-bottle setup saved a median of 8 watts, and 14 watts for the best measured rider, versus riding with no bottles at all. The bigger gains came from riders whose previous setup forced air around their forearms; the smaller came from riders already running a very tight position. Either way: faster than a downtube bottle, and easier to drink from at race pace.1
Why a BTA helps
Front-mounted bottles sit inside the cleaner air between your arms, instead of breaking the flow at the downtube. That smooths the air over your chest and head — the largest frontal area on the bike. Done right, you get hydration that's faster, easier to reach mid-effort, and quicker to refill at an aid station.
What you get from an AeroGain BTA
- Modular spacer system — dial the bottle height and angle to your fit, not the other way round
- Fits standard aero cockpit extension clamps and most TT base bars
- Tested at 45 km/h at Ballerup Super Arena, Copenhagen, on real triathlon positions — not just a CFD render
- Available to fit extension angles from 0 to 30 degrees.
Choosing your BTA setup
Start with the complete mount, then if you later want to fine-tune different options, BTA spacers can later be bought separately to try out more variations in bottle positions, to match your extension stack and reach. If you're unsure, send us a side-on photo of your current position — we'll point at the spacer combination that fits.
Frequently asked
How much faster is a BTA setup, really?
In our velodrome testing across 35 athletes at 45 km/h, the median saving was 8 watts, and 14 watts for the best measured rider, versus riding with no bottles at all. A handful of riders were within a watt of neutral — typically those already running a very tight aero position. The gain over a standard downtube bottle is larger again.
Will it fit my cockpit?
The AeroGain BTA mounts to standard TT and triathlon extension clamps and works with most aero cockpits on the market. Some of the bikes that we have confirmed fit are Specialized Shiv or S-Works Shiv TT, Trek Speed Concept, Cervélo P5X, BMC Speedmachine, Canyon Speedmax CF7, Cube Aerium and similar.
¹ AeroGain in-house velodrome population testing, Ballerup Super Arena, Copenhagen: n=35 athletes, test speeds 35–50 km/h normalised to 45 km/h, baseline CdA 0.165–0.237, reported as power saved at 45 km/h versus riding with no bottles at all. Median 8 W, range neutral to 14 W. Not all riders tested every setup. Individual results vary with rider position, bottle size and yaw. Test conditions available on request.
