Review | Giant’s latest Rail SX MIPS helmet has more coverage and clever goggle compatibility

Giant may be best known for popular mountain bike models such as the Anthem, Trance and Reign, but the Taiwanese manufacturer actually has a pretty huge array of components and accessories too. Alongside carbon fibre wheels, dropper posts and flat pedals, you’ll also find a pretty comprehensive range of off-road riding kit, SPD shoes and even helmets.

The Rail SX MIPS on test here is Giant’s premium open-face lid designed for trail and enduro shredders. It sits above the cheaper Rail and the Roost helmets.

Though it looks very similar to the existing Rail helmet, the Rail SX is structurally unique, with greater coverage, an updated retention system, and a sleeker integrated MIPS liner.

This has been my first head-on experience with a Giant-branded helmet. Having recently ridden with Troy Lee Designs A2, Specialized Ambush, Bontrager Rally and Bell Sixer helmets, I was intrigued to see how Giant’s latest brain bucket would stack up. To get yourself acquainted, here’s the rundown;

Giant Rail SX MIPS Helmet Features

• Open-face helmet designed for trail and enduro
• Fusion in-moulded polycarbonate shell
• Integrated Multi-Impact Protection System (MIPS) liner
• Low-density EPS foam construction
• 20 vents
• Adjustable and removable visor
• Cinch One Pro™ fit system
• TransTextura Plus™ anti-microbial padding
• GoPro™ curved mount compatible for cameras and the new Giant Recon light system
• Claimed weight: 360g
• Sizes: Small (51-55cm), Medium (55-59cm), Large (59-63cm)
• Colours: Matte Black, Matte Orange, Matte Blue
• RRP: £119.99 / $184.95 AUD

Enduro Design

As with the existing Rail, the Rail SX has been designed with input from the Giant Factory Off-Road Team, which includes the likes of Eliot Jackson and Josh Carlson. The priority for the team was to create an open, ventilated helmet design with plenty of coverage for impact protection, while also being fully goggle-compatible.

The Rail SX is a dedicated open-face helmet, so unlike the Bell Super DH and Giro Switchblade, you can’t covert this into a full-face lid. The thick EPS foam shell does have a large degree of coverage though, and compared to the standard Rail, the entire profile is deeper; 3mm lower at the front, 3-5mm lower at the sides, and 8-10mm lower at the back.

The whole lid is wrapped with a two-part polycarbonate in-moulded shell. There’s the top coloured component (matte blue in this case), along with a neat transparent strip that covers the underside of the helmet rim. Although it looks like exposed EPS foam, it’s actually protected by a thick plastic layer.

Our test helmet came in a little over the claimed weight at 376g, but it sits well alongside its MIPS-equipped competitors, which includes the TLD A2 (382g), Bontrager Rally (391g), and Bell Sixer (400g). Only the Specialized Ambush is lighter (297g), though it is also one of the slimmest ‘trail’ lids on the market.

Fit & Adjustability

With a bog-standard cranium circumference of 56cm, I’ve been riding a Medium sized Rail SX. The fit has been spot-on for me, though it’s worth noting that the internal profile is a touch more ovoid than round. Compared to the Bell Sixer, Bontrager Rally and TLD A2, the fit is more snug around the sides, with less hollow space between the shell and the sides of my noggin. The result is a nicely secure fit, with very little interference from the discreet MIPS liner.

However, I have found there to be limited clearance where the helmet rim drops down over my temples, which can cause fit issues with certain sunglasses. With a pair of Smith Attack Max glasses for example, the helmet would push down on the arms, which would result in added pressure and discomfort on the nose pads. As always, we’d recommend trying on a helmet before buying, but I’d also suggest taking in your riding glasses to check compatibility before assuming they’ll fit.

Retention duties are handled via a single rotary dial at the rear, which allows for easy fine-tuning of how tight the helmet wraps around your head. Adjustable anchor points inside the shell mean you can alter the vertical position of the rearward cradle, so it sits in the right spot underneath your wisdom bump.

There’s a single chin buckle for locking everything down, with thin straps that can be easily adjusted around your ear lobes. The straps themselves anchor to the underside of the rim, which I’m not normally a fan of, as I prefer to wear my sunglasses over the straps. It isn’t a huge deal here though, and the Rail SX feels plenty sturdy when on, with very little wobbling – even with the MIPS liner.

Goggles Up

Giant has used a couple of neat tricks to ensure goggle compatibility with the Rail SX. There’s an elastic cord around the back of the helmet, which features a push-button latch to lock down your goggle straps securely. It’s simple, but a really nice feature that’ll reassure those who worry about goggle straps sliding free during a race run.

The adjustable visor also kicks up high enough that you can easily stow the goggles on the front of the helmet, whether you’re on a transition stage, or jumping into the shuttle bus on your way up to another descent.

The Rail SX fits goggles neatly, thanks to a raised section around the forehead, which provides plenty of clearance even for bigger MX-style goggles.

The only downside is that if you’re wearing glasses instead (like I do 95% of the time), you do end up with a bit of a gap between your riding glasses and the helmet rim. I tried to adjust this out by changing the vertical position of the harness, but bringing the helmet further down over the forehead simply compounded the glasses interference. So I’ve learned not to mind the gap.

Speaking of glasses, you’ve got two options for storing them on the Rail SX. You can stick the arms through the frontal vents, and then lock the visor down over the top of the lenses.

Alternatively, you can fold in the arms and attach them onto the helmet via the elastic strap at the back. Either solution worked fine for me.

On The Trail

With its comfy and secure fit, the Rail SX is easily forgettable while riding, and I truly mean that as a complement.

The 20 equally-spaced vents work exceptionally well at bringing in cool air, while also letting sweaty vapour to naturally elevate out of the helmet while climbing at slower speeds. Having ridden this helmet through the peak of a very hot Aussie summer, with numerous 40+ degree days, I’ve been very impressed at how cool it runs given the extensive coverage. That’s not really a big surprise given the influence of Aussie EWS shredder, Josh Carlson, in the design process for the Rail SX.

I’d say the Specialized Ambush is still the segment leader when it comes to ventilation, but the Rail SX isn’t too far behind.

Though I thankfully haven’t had any major stacks in it, I’ve smashed my fair share of low overhanging tree branches, and save for a few scuffs and small dents, the Rail SX is coped fine.

On the note of impact safety, it’s worth paying attention to just how thick the EPS foam is, particularly at the rear, the sides and the forehead of the helmet. It’s also pretty thick on top, and it does give the helmet a fairly bulky look. I’m not too fussed by that though, as I’d always favour an abundant crumple zone over a slimmer-looking helmet.

Stability has been very good, even while wearing a GoPro camera up top. To facilitate easy mounting, Giant has built in a flat surface on the centre-top of the helmet, which is perfectly sized for a stick-on GoPro mount.

From there you can either run a POV camera, or the myriad of helmet lights on the market that are compatible with the same system, including Giant’s own Recon lights.

Overall

With no prior expectations, I was pleasantly surprised by Giant’s Rail SX helmet. It’s got plenty of useful features, like the goggle/glasses stowage, and the low-profile camera mount. It’s also very well ventilated, and I personally got on with the fit really well – it’s a comfy lid no doubt.

I would like to see more clearance around the temples to reduce interference with glasses, but this is something to bear in mind with many of the latest full-coverage trail helmets, which tend to be bulkier around this area. Otherwise the Rail SX is a high quality, top value trail helmet.

Review Info