Giro Selector TT helmet

'The fastest production TT helmet available' is how distributor Madison describes the new Giro Selector. The front is more dome-like than many aero helmets and the tail is truncated. What's unusual about it, however, is that you can select (geddit?) the depth of the lower section of the lid, from the ear covers to the helmet tip.

Why would you want to choose the depth of the helmet? Because it lets you customise the fit, so that you can minimise or eliminate the gap between the underside of the helmet and your skinsuited back, thus making yourself more aerodynamic.

If your head position is really low relative to your shoulders, you'll want the section that's 10mm deep so that you can still look forward easily rather than getting your head tipped down by the tail. Most riders - including me - will want the 40mm section. Both are provided in the box and they just clip on and off.

Each lower section is covered on the underside rather than open, similar to the tail of a Spiuk Kronos. The underside of even an open-ended aero helmet is hardly a parachute, but closing this off can't hurt.

The front of the Selector has a visor, which clips off if you'd rather ride without. As stock, you get a smoke-tinted lens. A clear version is available separately (for £19.99) if you'd prefer that. Normally I would, but this smoke one is only lightly tinted. I had no problem seeing clearly through it during a cloudy, end-of-season TT where passing drivers were turning on their sidelights.

The visor didn't fog up with damp or sweat either. There are vents in the top, where it clips to the helmet, as well as small gaps between the visor edge and the ear covers. Any air getting in can escape via a couple of exhaust ports at the back of the helmet. It gets hotter than my old, open-faced Bell Meteor, but not so hot that you broil your head on a warm day. And let's face it: you're going to get hot anyway, aren't you? It's a time trial, not a country lane tootle.

The lower section of the helmet sits close around your ears. It's flexible here and has a soft lining, so your ears don't get completely squashed, but it's snug. At high speeds you get quite a bit of wind roar. You can still hear traffic.

There are two sizes: S/M, for head circumferences of 51-57cm, and M/L for 55-61cm. On paper, I would fit either. I tested the S/M, but in hindsight would want to try the larger one. Fit, as I said, is pretty snug, and there's less adjustability with this helmet than your traditional road lid. The chin strap is adjustable only for length, and there's no inner cradle as such - just a rear section, buttressed against the back of your head by a flexible plastic strut with three settings. I set it as far back as it would go. Despite the internal padding, I'd still get slowly fading vertical red lines on my forehead after each race, showing where my head pressed hard against the helmet ribs.

It's certified to EN 1078, so should offer more protection than a head fairing if you hit the deck. Giro supplies a lightly padded drawstring bag to prevent scrapes to the helmet in the boot of a car.

The real question with a helmet like this is: how fast is it? Not having access to a wind tunnel, I just did late season time trials wearing this instead of the Bell Meteor I'd normally use. There are lots of variables in a time trial - weather, traffic, how you're feeling, what you had for breakfast. Nevertheless, I got a 10-mile course PB and an overall 5-mile PB while testing the Selector. I was consistently faster, not just in relation to my own times but also to those of my peers. I don't think that's a coincidence.

How much time will it save you? Hard to say. If you've got a great aero helmet already, which sits right against your back, then not much; maybe even nothing. If you've got an entry-level aero helmet that doesn't fit snug to your back, maybe a second or two a mile, judging by my results. Is that worth the £240 price tag? Only you can answer. Yes, it's twice the price of some aero helmets. But you're still probably getting more bang for your buck than if you bought an expensive aero frame (assuming the same riding position is achievable on a less aero frame). And who doesn't do that after a few seasons of TTing?

The ultimate question is whether it'll suit the head/back position that you have when you're time trialling. I think that with the 40mm deep lower, it'll suit most riders. The only way to be sure is to take your TT bike, your turbo and a camera to the shop when you try on the Selector!

It's available in black, red/black, blue/black, and white/silver.

Verdict

An expensive pro-level aero helmet that's properly fast - if it suits your head/back position