Custom Aero Bars: Why S/M/L Sizes Hold You Back (and How a Made-to-Measure Cockpit Is Built)

Your body doesn't come in S, M or L

Think about how you choose conventional aerobars: you look at a catalogue, pick between two or three standard sizes and, once they are mounted, you start making compromises. You move the saddle forward a little, turn the extensions "more or less" to where your forearms feel right, bring your elbows in as far as the bracket allows… and the result is a position that only half works: you last 20 minutes on the bars and your body starts begging to get out of there.

The problem isn't you. It's the approach. The length of your forearm, the width of your shoulders, the mobility of your back and even the way you rest your wrists are yours and no one else's. A mass-produced aerobar can't know any of that. That is why at CarboXtrem we do the process the other way round: your measurements first, then the part. Every cockpit of our custom Aero aerobars is built around the rider who will use it, whether for road, gravel or triathlon, and for any brand of bike.

Why the aero position only pays off if you can hold it

Aerodynamics is the biggest brake you face as soon as you go above ~30 km/h, and most of that drag is generated by your own body, not the bike. Aerobars let you narrow your frontal area and gain "free" watts… on paper. In practice, the aero position is only worth as much as your ability to hold it: an aggressive angle is useless if after half an hour your forearms are numb, your neck is loaded or your wrists are bent at an unnatural angle.

This is where customisation stops being a luxury and becomes pure performance:

• Reach and width matched to your body: the rests sit exactly where your forearm naturally lies, not where the manufacturer decided.
• Wrists positioned at 50º: the optimal angle that reduces strain on the wrist and forearm and lets you hold the extensions relaxed, without "gripping" them.
• Adjustable tilt from 0 to 35º: from a classic flat position to the high-hands setups that have taken over modern time trialling.
• Extensions that can be angled towards the centre: to narrow your frontal area and ride in an "arrowhead" position when the rules and the event allow it.

How a CarboXtrem cockpit is built: three technologies, each in its place

1. Structure: hand-laid carbon fibre

The structure of the aerobar —the part that carries your weight and transmits every pedal stroke— is made by hand, ply by ply, in T1000-grade carbon fibre, one of the highest grades there is. It doesn't come out of a mass-production mould: each part is laid up by hand, which lets us orient the fibre where the load demands it and achieve an assembly that is extremely light and stiff at the same time. It is the same approach as top-level racing: craftsmanship and aerospace material, not injected plastic.

2. Fit: parts 3D printed in aerospace-grade nylon

Here is the secret of millimetre-perfect customisation. The cockpit's mounting and adjustment parts are 3D printed in aerospace-grade nylon, which frees us from the limits of a size catalogue: we can make exactly the geometry your position needs —angle, width, reach and height— without compromise. If your bike fit says 3 mm higher and 2º more rotation, the part comes out of the printer 3 mm higher and rotated 2º more.

3. Contact: 3D lattice arm rests with density tuned by zone

The point where your body meets the bike deserves a chapter of its own. The arm rests are 3D lattice structures made by Carbon (DLS technology) to a CarboXtrem design, in EPU 41 elastomer: thousands of open cells that deform in a controlled way, absorb road vibration and let air through. And each lattice is optimised in density and size for the rider: firmer where you push, softer where you only rest. It is the difference between a lump of pad-shaped foam and a structure designed for your forearm.

CarboXtrem Aero aerobars at a glance

The same bike, a different bike

Perhaps the best part: you don't need a time trial bike to get a serious aero position. The aerobars mount on the handlebar of your current bike —the road bike you train on, the gravel bike you ride ultra-distance on— and turn it into a machine fit for breakaways, endless flat stretches and triathlon bike legs. When time trial season is over, you take them off and your bike goes back to what it always was.

Each set is made to order from your measurements (and if you have a bike fit, we make the most of it). European manufacturing, from our workshop to your bike.

Frequently asked questions

Will they work on my bike even if it isn't a triathlon bike?

Yes. They are clip-on: they mount on the handlebar of road, gravel or triathlon bikes of any brand, and come off when you don't need them.

What information do you need to customise them?

Your body measurements (forearm length, shoulder width) and your target position. If you have a bike fit, we build it into the design.

Are the aerobars 3D printed?

Not the whole part. The structure is hand-laid T1000-grade carbon; what is 3D printed are the mounting and adjustment parts (aerospace-grade nylon) and the lattice arm rests (Carbon DLS, EPU 41).

Can I mount electronic shifting buttons?

Yes, they come ready for SRAM Blips and Shimano mounts.

What warranty do they have?

Lifetime, like the rest of CarboXtrem's components.

Stop adapting to your aerobars

If you are serious about your aero position, the first watt you need to win is a cockpit that fits you. Tell us your measurements and we will build yours: hand-laid carbon, millimetre-perfect 3D-printed fit and lattice rests that last as long as the stage does.

Discover the CarboXtrem Custom Aero Aerobars →