Accessories specialist ENVE has announced an all-new addition to the Smart ENVE System (SES) component line. The company notes that its new SES Aero Road Stem is designed to make riders faster and does so in three ways: by enabling riders to achieve their optimum position, by reducing drag through aero shaping, and by preserving handlebar options.
It follows the philosophy of ENVE’s SES Aero Road Handlebar, which was first launched in 2013 and introduced this multi-faceted approach to boosting speed. The SES Aero Road Stem was developed with input from ENVE’s partners Team Dimension Data. ‘Sprinting legend Mark Cavendish and lead-out man Mark Renshaw were the first to ride the new stem and gave valuable feedback.’
ENVE notes that, while professional racers often use a more aggressive position, their objective is always to achieve the most efficient position ergonomically, biomechanically, and aerodynamically, and this applies equally to all riders. By making the stem adjustable, ENVE is ‘enabling every athlete to hone their position to perfection’.
Like every ENVE SES product, the Aero Road Stem is designed to reduce drag, with an aerodynamic shape, a low-profile clamp, and the option to set it flat for minimal frontal area. However, its adjustability is potentially of even greater benefit, allowing riders to achieve an aero position that is sustainable for hours. It does this using two steerer clamp shims, each of which can be positioned two ways; use one to tune the bar height by switching the angle between -7 ̊ and -17 ̊, with a fixed length, or use the other shim to tune the length by +/-2.5mm with a fixed -12.5 ̊ angle.
The standard 31.8mm clamp means riders maintain a free choice of handlebar model and position. To ensure that these gains aren’t negated by a bike computer, an integrated mount has been developed in partnership with experts K-Edge.
Jake Pantone, ENVE’s VP of Product and Consumer Experience, said “SES component development is built on the concept of ‘Fit is Fast’, meaning a rider is only as fast as their body position on the bike allows them to be. While each SES product is aerodynamic by design, it is what the product, in this case the stem, allows the rider to do with their position that ultimately helps the rider go faster.”
The aerodynamic design for the stem was carried out in CFD (computational fluid dynamics software) by Smart Aero Technology and then honed at the Mercedes AMG Petronas F1 wind tunnel in Brackley, UK. Wind tunnel testing of the stem revealed a small but valuable 0.6W average gain through a full sweep of wind angles at 40kph compared to the classic Road Stem.
The SES Aero Road Handlebar saves a further claimed 5W. ENVE adds that by far the biggest gains come when the rider is included in the testing and the position is optimized using the shims – while drag savings will vary between riders, gains of 15-30W are said to be common.
ENVE’s Chief Design Engineer, Kevin Nelson, explained “The primary goal here is to get your optimal position on the bike. The purpose of the shim is to achieve that as aerodynamically as possible by reducing the need for headset spacers. Round spacers are aerodynamically inefficient, so being able to adjust the position of the stem without adding them is beneficial.
“Additionally, reducing the aerodynamic footprint of the bolts and mounts further minimizes drag.”
Consultant aerodynamicist Simon Smart, of Smart Aero Technology added “Because the rider causes around 80% of the total aerodynamic drag, it’s essential to find the optimal position that combines aerodynamics with comfort and efficiency. My experience of positioning many of the world’s top riders has taught me that even a good position can be refined to produce significant gains.
“The adjustability of the SES Aero Road Stem enables precisely such refinements. In addition, its shape reduces drag compared to a classic road stem.”
The SES Aero Road Stem is available now, in lengths from 100-140mm, priced at US$300.