EXT Aria Review

The Aria is EXT’s first mountain bike air shock. In the bike and moto scenes, EXT are renowned for their coil shocks, but this isn’t the brand’s first rodeo, because EXT have worked with air shocks in Formula 1 as part of the Williams Active Suspension project.

The Aria (Italian for “air”) is positioned very much at the high-performance end of the shock market and with it, EXT have created something that’s genuinely unique, innovative and differentiated.

In order to create a shock that is highly sensitive to small bumps and yet avoid the rapidly rising spring rate that air shocks are subject to, EXT have adapted the twin positive air chambers used on their Era fork for the Aria.

AS3 Twin Chamber

Unlike most air shocks on the market, the Aria does not use volume spacers to help tune the shock. This brings a number of immediate benefits. Firstly it allows for greater control over the shock’s spring rate, allowing for tuning through the full stroke, rather than solely at the end of the stroke as a spacer would.

When you add a volume spacer to a shock’s air chamber it reduces its volume which means the air inside is compressed more rapidly and sooner in the stroke of the shock. Consequently, the spring becomes more progressive near the end of its travel. This can be very useful, but the volume change will also affect the entire stroke of the shock. Adding spacers to try and increase mid-stroke support will result in a more rapid rise in spring rate at the end of the stroke. Similarly, removing spacers to reduce that ramp-up will reduce mid-stroke support.

The twin chamber approach is also much more convenient for tuning as the shock doesn’t have to be removed from the bike to add or remove spacers, nor does the air can have to be removed. Considering that you may have to remove the shock multiple times before you get your spacer/spring set up the way you like it, this is very handy.

Each of the Aria’s two positive chambers has its own valve. The + chamber, provides the primary support for the system and controls the sensitivity of the top and mid stroke. Meanwhile, the second, ++ chamber controls the sensitivity of the middle and end of the shock’s stroke.

It’s a more nuanced and precise approach that means the user doesn’t have to compromise small bump sensitivity for mid-stroke support or conversely sacrifice the shock’s ability to deal with big hits at higher speeds.

The pressure in the + chamber sets the sag position and affects the overall feeling of the shock. The higher the pressure in this chamber, the stronger the spring throughout the stroke of the shock, as per a regular air shock.  The shock’s performance can then be further tuned by adding or reducing the pressure in the ++ chamber, enabling the user to create a  more linear or progressive air spring curve.

More pressure in the ++ chamber gives you greater mid and end stroke support without compromising sensitivity off the top. The combination of the two chambers allows for the creation of a more linear rate throughout the stroke. EXT talk about it offering a “pure coil feeling”.

“Unlike most air shocks on the market, the Aria does not use volume spacers to help tune the shock. This brings a number of immediate benefits.”

Adjustable Hydraulic Bottom-out Circuit (HBC)

As with EXT’s coil shocks, the Aria incorporates a hydraulic bottom-out control to prevent harsh bottom-outs. The HBC system engages in the last 15% of the stroke and is externally adjustable to match your weight, riding preferences and style.

LOK 2.0

The Aria also features EXT’s LOK 2.0 system that allows you to firm up the shock for pedalling if required.  When closed, LOK pushes oil through a preloaded shimmed valve increasing compression force. This still allows for some sensitivity and traction on rough surfaces without being a “lockout”. LOK can also be custom tuned, based on rider preferences.

Adjustments

As you’d expect with a high-end shock that’s as tunable as this one, The Aria also features rebound, high and low speed compression adjustments. Changing these makes as noticeable difference to the feel of the shock and there’s a good range to experiment with, although incessant knob-twiddlers will need to keep tools handy as there a no dials to play with on the compression adjusters.

What makes the EXT purchase experience different?

EXT is distributed in New Zealand by Queenstown-based suspension tuners EXT New Zealand, which means that each shock purchaser’s experience can be absolutely bespoke. When you purchase an EXT shock, you don’t simply walk out of the store and bolt it to your bike, pump it up and turn the dials until it feels right. Each shock is set up by the team at EXT New Zealand for the specific customer’s bike, weight and riding style. Yes all the parts are off the shelf, but your shock will be unique to you and your bike.

Once you’ve decided to purchase an EXT, you’re asked to fill out a web-based form that details everything EXT New Zealand need to know to build your shock, which is then  tested on their dyno to ensure it will deliver what you need it to do on your bike.

The shock is then shipped to you with all the appropriate hardware accompanied by a certificate from the builder and all of the recommend settings for the shock. The package also includes a shock pump capable of up to 600psi in order to deal with the higher pressures needed in the ++ chamber.

How does it feel on the bike?

Once bolted to our 25kg e-bike test rig, we found the recommended settings to be very effective. Root gardens and braking bumps are easily dealt with and yet without the classic mid-stroke wallow that air shocks can suffer from. That support helped the bike from sinking too deep in high speed berms and working through the travel too quickly in rockier terrain. Big hits were comfortably despatched and the hydraulic bottom out does seem to be very effective. Moving into rockier terrain we ended up adding a little extra pressure to both chambers and an extra click of rebound. That “propped up” feeling in the mid-stroke was very welcome in situations where we’d of previously  encountered pedal strikes or scraped through on the skidplate.

The compression adjustments are easily accessed but the HSC requires a ring spanner and the LSC an allen key to make changes. Perhaps that’s a good thing given how effective the shock seemed to be in EXT’s recommended (and dyno tested) settings. But if you do make adjustments, you’ll find a useful range of noticeable adjustment is possible. After some experimentation, we’ve found ourselves back at the very satisfactory original recommendations, which says a lot about the benefits of a bespoke build like this.

“Coil like” is a common refrain we hear when people talk about what they’re looking for from an air shock and it’s repeated in the promotional material from EXT. Is it really “pure coil” in feel?  From our experience, it’s still definitely an air shock in character – the “pop” that air shocks have is very much alive, but the Aria with its large negative chamber breaks away very easily and is supple and compliant over small bumps. The linear feel the two chambers are intended to deliver is also apparent in that there’s definitely less impression of a rapid ramping up of the spring rate on big hits and the HBC definitely plays its part. Sure you can feel those hits, but they’re managed extremely well.

“Root gardens and braking bumps are easily dealt with and yet without the classic mid-stroke wallow that air shocks can suffer from.”

Overall Opinion

This is a pricey piece of kit, but it’s definitely one that enhanced the bike’s performance whilst we’ve had it. That price point is however more or less the same as purchasing any other top-end shock off the shelf and getting it appropriately tuned to your requirements.

How much of the enhanced performance is a factor of the shock technology versus having the shock set up appropriately and dyno tested is a question it would be interesting to get to the bottom of but so far our experience with the Aria has been excellent. It’s highly tunable, impressively smooth and offers excellent support. It’s not quite as supple as the E-Storia coil shock we tested last year, but it’s certainly closest to a coil feel of any air shock we’ve ridden to date. We expected that those two air chambers might require double the monitoring of pressure, but during the test period, we’ve not found air loss to be a problem at all.

One issue that has arisen is that the hose connection on the shock pump provided broke whilst we were adjusting the pressure in the ++ chamber. As regular shock pumps can’t achieve the required pressures, this proved to be a problem until EXT New Zealand were able to replace the pump.

Who is it for?

The kind of rider who will get the most out of this shock is either someone looking to know that their set-up is totally dialled through the custom rider/bike tuning that EXT offers through EXT New Zealand or someone who loves to experiment and is keen to explore the effect of altering pressure in the twin chambers. Either way, neither customer type will regret fitting this shock to their frame.

Some people won’t like the lack of tool-free compression dials, but in our case, it actively discouraged us from messing up a shock that had been effectively tuned and worked just great!

EXT Aria review