From Nose to Tail: Factor OSTRO Gets Comprehensive Aero Upgrade

The OSTRO is the bike that encompasses Issue and its presence worldwide. It’s probably the most recognizable (IMO) and interesting of its choices and helped form the mould for highly effective highway machines with a slippery silhouette. The brand new OSTRO doesn’t transfer removed from the unique start line however goes all in on minute aero updates for bigger features.

(All photographs: Issue Bikes)

When it got here time to revamp the bike, the Issue design crew seemed to stability stiffness/consolation, real-life aerodynamics, and wonder. The crew added some cool further bits like distinctive aero bottle cages and a brand new set of ultra-fast (and really handsome) Black Ink 48/58 Wheels.

Issue OSTRO – Aero Makeover from Nostril to Tail

Growing the 2024 OSTRO, Issue checked out each tube and targeted on understanding how the bike’s form may strategically information air across the rider. They began at the forefront and labored backward.

Whereas presenting the brand new OSTRO, the Issue design/aero crew defined that Enhancements on the entrance impression parts on the rear, making a snowball impact of features and losses. The Issue design crew divided this aero-challenge into 5 ‘zones’ to attain probably the most aerodynamic edge whereas sustaining the bike’s total trip integrity.

Zone 1 — Fork and Headtube

The fork impacts the aerodynamics of your entire bike because the central a part of the bike’s vanguard. The CDA (drag coefficient) was lowered by minimizing the frontal space and rising form effectivity. The newly lowered fork crown peak improves the brand new OSTRO’s stiffness and really feel. The trip really feel and responsiveness are an indicator of the OSTRO, and the crew didn’t wish to lose that feeling amid aero features.

Issue then gave the brand new OSTRO’s headtube a extra hourglass form, lowering the frontal space. Including a nostril on the headtube allowed the crew to maneuver the forefront of the fork ahead, making a smoother transition for the nostril with the headtube.

Aero Fork on the within: Small floor particulars have been added on the within of the fork leg that work with the rotating wheel to advertise higher circulate. The dropout and brake mount surfaces are modeled to maneuver the air from the axle. All these small particulars add as much as create a pleasant chunk of aero-gains.

Zone 3 — Headtube to Toptube

The up to date head tube made approach for a have a look at the general airflow coming to the highest tube. The crew targeted on smoother circulate from the headtube to the bike’s rear. A streamlined headtube-to-top-tube transition enhances circulate attachment and creates a extra slippery design. This slimmer prime tube paves the best way for an total discount in seat tube measurement for a streamlined profile.

Zone 4 — Seat Tube

Now that the UCI has eliminated the three:1 rule (about two years in the past) for parts and lowered the minimal tube thickness required, the design crew at Issue may develop a slim seat tube that labored nicely with the aggressive tapering on the highest tube.

The crew’s goal was to take care of stiffness whereas lowering frontal space. Consequently, the decrease sections of the seat tube stay as huge because the OSTRO body. It tapers into the underside bracket zone (zone 5) and requires further carbon layup magic to fight the dreaded torsional flex.

Zone 5 — Backside Bracket

The business development is to make the underside bracket wider, taller, and barely boxy (just like the Trek Madone). Issue added their spin on this with the brand new OSTRO, making a clean but boxy backside bracket junction. The crew began, “Balancing form effectivity and sustaining quantity and rigidity is vital to energy switch. Right here, we needed to handle the pedaling forces in a single aircraft whereas selling airflow retention within the different.”

As for the peak, the design crew meticulously fine-tuned the amount above the underside bracket, balancing airflow whereas conserving it tucked away from the riders’ legs. As soon as once more, the Issue crew discovered a slight acquire in aerodynamic effectivity, including one other tick within the quicker route.

Black Ink 48/58 Wheels:

When Issue drops a brand new bike, it normally means one other cool wheelset, and the BLK Inc 48/58 isn’t any exception. The latest BLK Inc. wheels characteristic a high-flange carbon spoke hub and weigh in at a brilliant gentle (for this deep) 1270g. The wheelset is aero-designed and examined for maximal efficiency with 28mm tires.

The elevated modern radius improves circulate attachment at bigger yaw angles, and the high-flange hub will increase trip really feel and lateral stiffness.

Issue design crew explains: “The elevated radius creates a extra gradual charge of curvature change, selling circulate attachment at bigger yaw angles. As well as, the rounder profile and extra gradual change in curvature implies that the aerodynamic stall onset is gentler, giving the rider a greater feeling of management in gusts and powerful crosswind conditions.”

Aero and Tube Particular Water Bottle Cages

Not solely are these new Issue/BLK Inc cages aero, however they’re tube-specific. In contrast to different aero cages, they don’t require a particular bottle or an attachment.

Black Ink–Tube Particular Bottle Cage: The BLK Inc OSTRO downtube cage bridges the hole between the downtube and the water bottle. It promotes longer circulate attachment and reduces localized drag — plus, it holds a water bottle!

Ostro Dash Cage: The Issue design crew selected a unique aerodynamic strategy for the Dash Cage. It acts as a high-speed circulate administration machine. It’s most aerodynamically useful when a rider ejects their bottle earlier than the ultimate dash. The foil profiles and exact spacing with the seat tube funnel air tightly throughout the tube and transition it to the rear wheel. Making you quicker for the instances when it’s completely wanted — like a tour stage or a city line dash.

The Full Image — Issue OSTRO 2024

So, how a lot quicker is the brand new Issue OSTRO in comparison with the earlier era? The brand new design saves 7 watts. Now I do know what you’re considering: “All that for 7 watts?!” However that’s quite a bit relating to an already super-aero bike.

The Issue design crew explains: “As for aerodynamics, the online acquire is roughly a ten% enchancment in aerodynamic effectivity with all variables managed and normalized in a wind tunnel. That is, on common, a 70-gram discount in drag vs. the unique OSTRO. That is about 7 watts at 48km/h, which converges with our simulation knowledge. As well as, the aerodynamic profit will increase as yaw angles develop into nearer to real-world expectations (5-10 levels).”