Fox Speedframe RS helmet review: a well-vented lid that tops the rankings for safety, if not comfort

We all know a helmet's primary job is to protect your head in the event of a crash.

It’s impressive, then, that Fox's new Speedrame RS tops the table in Virginia Tech’s independent helmet-safety rankings.

In fact, all three of the new Speedframe helmets get a full five-star rating, with the £224.99 RS and £164.99 Pro topping the table in first and second respectively, which is impressive stuff, considering they're up against some stiff competition out of the 258 lids that have been tested.

The Speedframe RS delivers on the trail, justifying the high asking price.

Airflow through the helmet is impressive, as are the rider-friendly features, including the moveable visor and magnetic Fidlock buckle.

The level of comfort is decent, too, but on longer rides I could start to feel the wire used on the retention system pressing into the sides of my head.

I’ve worn the Speedframe RS on and off for a good few months and will continue to wear now testing is complete, which says a lot. However, there are a couple of things that could be improved.

Fox Speedframe RS specifications

At the heart of the range-topping Speedframe RS lid is the MIPS Integra Split system.

This nifty safety system features two foam shells of different densities, connected with elastomers, with a low-friction layer between the two.

The idea here is that enabling the outer shell to move over the inner will reduce the rotational forces your head is likely to encounter if you hit the dirt at a funny angle (think a ball and socket joint).

While the outer foam is of a higher density (to deal with high-speed impacts), the inner shell – which is split into two sections – is made from lower-density foam (better for slower-speed knocks).

The different-density foams, coupled with the small amount of movement between the two shells, should help to reduce impact forces reaching the brain.

The Speedframe RS helmet uses a Fidlock magnetic buckle, along with an adjustable cradle, to help clamp it in place.

Fox now uses a Boa system to lock this in place, complete with an indexed Boa dial. The cradle itself wraps the entire circumference of the head, which should help in producing a nice, even tension once it's fitted. There’s also the option to tweak the vertical position of the cradle.

Other features include channels and rubber grippers for storing MTB glasses when not in use, as well as an adjustable visor with three distinct positions to choose from. This should make life easier when wearing MTB goggles.

The Ionic+ padding is removable, so you can wash it before it gets smelly. There are numerous vents, coupled with some internal channelling that should help keep your head cool when you’re working hard.

There are three sizes to choose from (S-L) and plenty of colour options.

My medium sample weighed in at 404g.

Fox Speedframe RS performance

Because my head measures 56cm, I opted for the medium helmet, which is designed to fit head sizes of 55-59cm.

Slipping the Speedframe RS onto my head, the helmet felt instantly comfortable.

The padding is just the right side of plush, adding a nice cushion between you and the lid, yet it's not so thick that the connection between the two ever feels vague.

It’s worth remembering that helmet fit will always be subjective. My head tends to fit Giro and Bell helmets well because it’s more of an oval shape.

Because of this, while I felt the Speedframe RS fitted perfectly at the front and back, I had to ratchet up the Boa dial on the retention system so it hugged my head securely.

Surprisingly, this didn’t cause any discomfort or hotspots initially. However, if I rode for hours on end without removing the helmet, I found the wire around the circumference of the helmet could be felt either side of my head, applying just enough pressure to cause irritation rather than outright discomfort.

Weirdly, I only picked up on this after I’d had my hair cut, reducing the natural padding over my head.

Switching to a deeper band-style retention system might alleviate this entirely. However, I’d recommend trying before buying, as I would with any helmet.

I like the quick and easy-to-use Fidlock buckle, as well as the adjustable visor.

While I never had any major issues with the Speedframe’s predecessor, I’d have liked to be able to shift the visor up a bit, especially on the rare occasions I’ve opted to wear goggles with a trail helmet.

With the new RS version, that’s not a problem, and moving it up and out of the way is easy.

While the glasses storage is great to have, locating the slots to stash your specs takes a bit of practice and can be a little fiddly, especially when wearing thicker winter gloves.

Once you manage to slot the arms into the designated slots, the little rubber bumpers do a great job of gripping the glasses so they’re secure enough.

Thanks to the massive ports across the brow and around the front of the Speedframe RS, ventilation here is superb.

Even at slower speeds, you can feel the cool air trickling in and drying the sweat on your brow as it's whisked past and then continues over your head via the internal channels.

In this regard, it’s certainly one of the best mountain bike helmets.

Finally, over rough ground, where you find yourself bouncing about, there’s no noise from the Split System. Early Giro lids with the brand's ‘Spherical’ technology, which uses a similar design to this, could get a little creaky at times. So far, the Speedframe RS has stayed silent.

Fox Speedframe RS bottom line

Dropping this sort of cash on an open-face trail helmet may seem hard to fathom for some. But when it comes to peace of mind – in fact, when it comes to your mind – it seems a small price to pay considering this lid tops Virginia Tech’s safety rankings.

While the Speedframe RS is not the outright comfiest helmet, due to the wire on the retention cradle, it is comfortable none the less, and airy too, thanks to the impressive ventilation.

There are a number of great features that make a lot of sense, too.

In short, if you have the cash, it's worth considering the Speedframe RS – but try before you buy to ensure you get the fit and sizing right.