Where the standard Aerohead MIPS is aimed for more mainstream time trial and triathlon use with a conventional polycarbonate shell and four external vents, the Aerohead Ultimate MIPS goes for all-out speed with a TeXtreme carbon fiber shell and no external venting whatsoever. Giro says the decision to use carbon fiber wasn’t driven by weight, however — and indeed, the Aerohead Ultimate MIPS has the exact same 450g claimed weight as the standard Aerohead despite costing more than twice as much. The Giant is fairly tight over the ears, likely a good thing in terms of aerodynamics, but can be a bit uncomfortable on longer rides. Personally, the Rivet TT would be great for short, hot time-trials or triathlon. active vents in the helmet's shell with exhaust channels inside the helmet that thrust fresh, cool air over and By using a polycarbonate shell, Wind Tunnel ventilation and internal channeling, this helmet is proven to boost Despite the minimal venting, Giro says the standard Aerohead MIPS is slightly better ventilated than the Selector, too. Unsurprisingly, the absence of external vents means the sleeker Aerohead Ultimate MIPS will be a fair bit warmer. Giro claims the new Aerohead MIPS and Aerohead Ultimate MIPS are measurably faster than its current Selector model. Photo: Giro. The ventilated Aerohead MIPS is slightly cooler than the current Selector while the non-ventilated Aerohead Ultimate MIPS is a fair bit warmer, according to company-supplied data. Photo: Giro

The Specialized comes with a pair of great visors: one tinted for bright conditions, the other clear. The optics are crystal clear with no appreciable distortion. Faster helmets are going to be warmer. That’s just the deal,” said Giro’s Dain Zaffke. “It’s always a game of compromise and trying to find the right balance.” The helmets on test were worn for at least 200km each, as well as being subject to aerodynamic testing using a Notio aero unit to measure the CdA changes vs a baseline road helmet.The two-piece shell combines a tough outer hard shell with a polycarbonate lower shell permanently fused to the liner

Like the POC and Giro, the Specialized comes with a zip closure, and semi-rigid storage case to keep your helmet and visors from getting dinged during transit. helmets. By creating helmet molds in up to 4 adult sizes to match the human body's form, our Super Fit sizes Giro helmets are developed utilizing our proprietary Wind Tunnel ventilation system. This elaborate design combinesWith that, it's worth considering not only the tint but also the quality of the optics and if spares are readily available for when you drop one.