Verdict
Head-to-head · Best Bike Helmets

Giro Aries Spherical vs Trek Velocis Mips

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

Trek Velocis Mips comes out ahead by a narrow margin (4.6 vs 4.4). The gap is mostly about riders seeking maximum breathability and low weight for performance road cycling — read the strengths below before deciding.

Giro Aries Spherical
Ranked #5 in Best Bike Helmets
Giro Aries Spherical
8 sources1 derived$21.95as of Oct 2

The Giro Aries Spherical achieves Virginia Tech’s highest safety ranking across all categories, utilizing a dual-shell ball-and-socket design to mitigate rotational impact forces more effectively than standard liners. GearJunkie found the helmet offers best-in-class ventilation through twenty-four vents that manage heat efficiently during high-temperature rides, while Cyclist magazine noted its DryCore system channels sweat away from the eyes with an internal silicone bead in the brow pad. However, Cyclist magazine measured a weight of 282 grams for a size medium, making it heavier than some direct competitors despite its premium price point. The product fits riders prioritizing maximum safety and cooling performance who can accommodate the extra mass and higher cost, but those seeking ultralight options or flawless build quality should look elsewhere.

Strengths
  • — Virginia Tech independent safety lab ranked the Giro Aries as its #1 rated helmet across road, mountain bike, and urban categories.
  • — Spherical MIPS technology uses a dual-shell ball-and-socket design to mitigate rotational impact forces rather than relying on a standard plastic liner.
  • — GearJunkie found the helmet offers best-in-class ventilation with 24 vents that effectively manage heat during high-temperature rides.
Watch-outs
  • — Cyclist magazine noted a measured weight of 282 grams, making it heavier than some direct competitors despite its premium price point.
  • — The helmet is expensive.
Trek Velocis Mips
Higher ratedRanked #1 in Best Bike Helmets
Trek Velocis Mips
8 sources

The Trek Velocis Mips is an ultra-lightweight helmet that weighs as little as 240 grams in small size and earned a five-star safety rating from Virginia Tech Impact Lab. BikeRadar found the BOA fit system precise, though Engearment noted the rear dial mechanism feels delicate when folded away for storage. The design prioritizes ventilation with sixteen vents claimed to be thirty-eight percent cooler than its predecessor, but In The Know Cycling reported that sunglass storage is inconsistent and straps are long enough to twist awkwardly around the ears. This helmet fits riders seeking maximum breathability and low weight who can accommodate specific fit adjustments, while those needing universal eyewear compatibility or a simple strap setup should look elsewhere.

Strengths
  • — Weighs as little as 240 grams in small size, making it one of the lightest road helmets available.
  • — Features a single-lace BOA fit system with multiple adjustment points for precise and secure comfort.
  • — Delivers exceptional ventilation, claimed to be 38% cooler than its predecessor due to optimized channeling.
Watch-outs
  • — The rear BOA dial mechanism folds away when stored and feels delicate or prone to getting out of place.
  • — Sunglass storage is inconsistent, with only flexible eyewear holding securely in the rubberized vents.
  • — Straps are long and can twist awkwardly around the ears, requiring careful adjustment.

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

How they stack up

Giro Aries Spherical

The Giro Aries Spherical offers superior ventilation with 24 vents compared to the Bell Formula's 19 and the Met Downtown's 17, making it cooler for hot rides. Its Spherical MIPS dual-shell design provides a different rotational impact mitigation approach than the standard MIPS liners found in the Smith Signal and Trek Velocis Mips.

Trek Velocis Mips

It utilizes a single-lace BOA fit system, which differs from the dial systems of the Giro Aries and Met Downtown, though reviewers note the rear dial can feel delicate.

Specs side-by-side

SpecGiro Aries SphericalTrek Velocis Mips
Weight265g - 282g240 g (Size S)
Ventilation2416
Safety TechnologySpherical MIPSMIPS Air
Safety CertificationCE EN 1078Virginia Tech 5-Star
Fit SystemRoc Loc 5+ AirSingle-lace BOA
SizeS, M, L—
VisorIntegrated visor—
MaterialPlastic—
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