TOOT Engineering’s MARASSHA3 Brings Unique Aero Approach To UCI Handlebar Regs

With the UCI’s upcoming change in regulations to handlebar dimensions, the reality is that brands need to work within the new guidelines. This means they need to become more creative and not just rely on a “narrow is aero” approach. Italy’s TOOT Engineering has a novel approach to bars that focuses on stability at speed, which also happens to put you in an aero position.

The MARASSHA³ (M3) is a collaboration with Bianca Advanced Innovations, COMPMECH University of Pavia, and Polytechnic of Bari to create a new road handlebar that blends riding stability with an aerodynamic approach. The bars use a riser design that sees them rise up from the stem clamp before flattening out to create a bit of a cradle for your forearms and transitioning to the lever clamps and down to the drops. They also have a bit of a forward sweep on the tops and a small amount of flare in the drops.

The “cubed” part of the M3 name comes the concept of integrating width (w – outside to outside of the drops), reach (r – from the center of the stem clamp to the farthest point forward on the drops), and stack (s – center of the stem clamp to the highest point of the tops) to create multiple geometries based on a rider’s physiology and intended use. The concept is what they call the Stability and Agility Factor, or StabFactor. TOOT Engineering defines it as (RxS) / (W/2) where W represents the effective width of the hand rests, not the total external width. The goal of the study was to prove this design concept maximizes a greater resistance to oscillations (shimmy/speed wobble), faster damping of bumps, better steering control at high speed through leaning, and a balance of passive stability and active control from the rider.

In the study, they compared three handlebar geometries, and found the optimized configurations can be up to 3.8 times more stable than traditional handlebars. Testing included a Digital Twin for testing how the handlebars would behave in various conditions and riding forces, testing on LITEM machines for physical validation of stiffness, FEM Analysis for structural optimization, and real world field testing by pros in training and races.

The stability study has shown that the geometry of the handlebar profoundly influences the human-bike system,” explains COMPMECH UniPv Research Team. “The StabFactor parameter we validated isn’t abstract theory, it’s applied physics that translates into measurable performance in the field.”

While the concept of wide bars make for better control is true at lower speeds, it is actually the opposite the faster you go. As speed increases, it acts like a sail that captures more of the external forces, like gusts of wind, bumps, etc, and can amplify them and cause speed wobble or shimmy.

Many brands focus on rider position in CFD and wind tunnel testing, but there is more to aerodynamic drag than just the rider’s position. In fact, CFD and wind tunnel testing ignores parasitic turbulences that come from the instability in movement. This includes oscillations (shimmy) that can come from the bike itself, and sway that comes from the cyclist when pedaling and steering. TOOT Engineering looks at all of these areas (rider position, bike and rider stabilization) to create a double aerodynamic advantage.

“In motorsport, we’ve learned that if you don’t control the vehicle, you’re not racing, you’re surviving,” explains the TOOT Engineering Team. “When we entered cycling, we found a world that chased watts and CdA, but ignored dynamic stability. M3 puts control back at the heart of performance.”

This led to three versions of the M3 being created. They all share the same width of 280mm center-to-center for the levers, and 399mm at the ends of the drops outside-to-outside (bar tape covers the 1mm needed to reach the UCI limit of 400mm). They have an effective support width of 325mm used for the StabFactor calculation, which essentially outside to outside of the tops. The difference from model to model is in the stack, reach, drop, and weight.

M3 COMP

• Stack – 48mm
• Reach – 123mm
• Drop – 72mm
• StabFactor – 36.33
• Weight – 295g
• Ideal for: Road, Mixed Surfaces, Gran Fondo

M3 RACE

• Stack – 53mm
• Reach – 138mm
• Drop – 67mm
• StabFactor – 45.01
• Weight – 325g
• Ideal for: Road Racing, Short Course Triathlon, Stage Races, Sprinters

M3 AERO

• Stack – 68mm
• Reach – 153mm
• Drop – 52mm
• StabFactor – 73.44
• Weight – 350g
• Ideal for: Time Trial, Long Course Triathlon, All Out Speed

If you look at the stem clamp as the static point, each model sees the top get higher and further forward as you go from the COMP to the PRO to the AERO.

While the looks might be different from traditional handlebars, the M3 can handle fully internal or external cable routing and is on target with the stiffness of their current production bar, the MARASSHA 4 3D CARBON.

Beyond the three models, you have the option for full carbon or 3D printed titanium. 3D printing also provides the option for a fully custom version, the M3 Custom, where you can tweak the dimensions as needed for your physiology and riding style.

So, back to that double aerodynamic advantage.

The M3 provides Position Optimization (aero-static) and Stability Efficiency (aerodynamic) advantages. By offering three versions, each with their own geometry (and the fully custom version), riders can pick the option that best suits their physiology and riding style, along with stem length, height and angle to find the right stack and reach numbers to find the best performance comfort zone. The design also helps to minimize the frontal area to match their riding style. For Stability Efficiency, the high dynamic stability of the M3 helps to suppress micro-oscillations and sway, which reduces the parasitic turbulence from movement. Basically, riders will be more stable, reducing movement coming from instability, and help them ride smoother. This helps to lower overall drag for the athlete/bike system.

If you want to dig deeper into the study, check out this link.

While it doesn’t matter for many of us, TOOT Engineering had to make sure that the M3 will be on the right side of the upcoming regulation changes for 2026. To be honest, the changes took many manufacturers by surprise as there was very little notice and left maybe 6 months of lead time before they go into effect. TOOT Engineering was able to incorporate the new regulations into the design process and quickly adapt. The minimum width of 400mm at the drops are achieved by a 399mm width, and the last millimeter being covered by tape.

The M3 will be available in January 2026, and come in at 539EUR, or about $625USD. If you are going the full custom route, they take about 2-3 weeks to make from the time you place your order and the cost is determined during the discussions with the client on their perimeters.

We are working with TOOT Engineering to secure a review sample for 2026, so check back for more about the brand, their current lineup of products, and maybe more about their track projects ahead of the 2028 Olympic cycle.

www.tootengineering.com