How to calculate the perfect height of your RocketTT risers?

In triathlon or time trial, the search for marginal gains is a permanent quest. We spend hours tracking down the slightest aerodynamic drag, testing positions, and investing in high-end carbon frames. Yet, a crucial detail is too often overlooked: the dead space between your arms, just under your hydration system (BTA).

RocketTT's philosophy is simple: eliminate this empty space so that your bottle surgically disappears in the slipstream of your hands and head, creating a perfect aero fairing.

But then, how do you know which riser height to order without making a mistake? No more headaches by email, we explain the workshop's mathematical method.

📐 The RocketTT Method: Chin ➔ Armrest Measurement

To calibrate your cockpit to the millimeter, everything starts with a single morphological measurement.

1. Put on your helmet (or simply get into your usual watt-hunting position).

2. Sit on your bike on a home trainer, or simulate your aero position in front of a mirror.

3. Take a tape measure and measure the exact vertical distance between the underside of your chin and the highest point of your armrest pads.

This value (generally between 150 mm and 250 mm) represents the total space available to stack your cockpit and accessories.

🧮 The Aero Integration Equation

Once you have this total height, you need to subtract the bulk of all the elements that will make up your new ultra-integrated cockpit:

• The bottle and its cage: Count 80 mm (essential, because even with a simple support, the bottle still needs to fit!).

• The RocketTT adapter plate: Count 10 mm for the base thickness of our rigid PAHT-CF plates.

• The V-FLOW Dual Bottle Holder option: Add 20 mm if you choose our profiled dual fairing.

• The Computer Mount option: Add 10 mm if you integrate your Garmin or Wahoo onto the system.

• The 10mm margin, because depending on the day, you might be positioned slightly differently on the bike.

The magic formula: > Remaining Riser Height = (Chin/Armrest Distance) - (Sum of your accessories & margins)

💡 What to do based on your result?

Our range of standard risers extends from 40 mm to 100 mm, which covers 95% of triathlon peloton needs with absolute aerospace rigidity thanks to our 4-hour heat treatment process.

• Your result is between 40 and 100 mm: Perfect! Select the exact value (or the closest standard size) on your bike's product page.

• Your result is less than 40 mm: Your position is already very low or your extensions are high. Contact the workshop directly; we can design specific ultra-low custom solutions.

• Your result is greater than 100 mm: This is mechanically possible, but for reasons of rigidity under extreme road stresses, we like to validate the project with you. Send us a quick message!

No more excuses for allowing turbulence between your arms. Get out the tape measure, start calculating, and gain the watts that will make a difference in your next goal! 🚀