Tour tech: world's lightest helmet debuts on stage 7

If the likes of Armstrong, Contador and Menchov aren't in the mix at the end of today's monster climb up to Andorre Arcalis, it won't be because their headgear was weighing them down. Giro's new Prolight lid debuts today and, at just 175g, lays claim to being the world's lightest.

The astute (and older) among you will remember the Prolight name: it's the moniker given to the first ever all EPS-foam lid created by Giro founder Jim Gentes back in 1986. That helmet adorned the head of the great Greg Lemond among others, and Giro claim the new Prolight is "just as froundbreaking and revolutionary". It's not, but it certainly is light.

How have Giro shaved precious grams from the new Prolight? The actual construction is similar to other top-end Giro lids, with in-mold construction that fuses the helmet layers together. Giro appear to have ditched the composite subframe used in the Ionos, though, in favour of a second shell inside the helmet - presumably to save a bit of weight. There's more vent than helmet, of course, with 25 big holes to get the airflow going on those hot Pyrenean climbs.

It's the fitting system where most of the changes are made. There's special new superlight webbing straps for a start, and the RocLoc system has been pared down to an elasticated strap and a three-position fore/aft adjustment which you should only need to adjust once. The whole of the adjustment system apparently weighs only five grams... even the buckle's had the lightweight treatment.

While it'll be adorning the heads of pros from now onwards you'll have to wait for a bit before taking your wedge down to the local bike shop. The Prolight is slated for release in early 2010.