Cube has just two models in its Reaction HPA range of hardtails. The longer travel TM with a 130mm travel fork and this, the Pro, with a more XC-orientated 100mm Rock Shox Judy leading the charge. And it’s not just the fork travel that sets them apart; they have completely different alloy frames.

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As you’d expect, the geometry numbers differ between both bikes, but so does the seat tube diameter, rear brake mount, bottom bracket standard and sizing structure.

Need to know:

• Sorted lock-on grips are best of the bunch
• Full Shimano 12-speed drivetrain performed faultlessly in all conditions
• RockShox PopLoc remote lets you lock out the 100mm travel Judy fork
• Shimano XT brakes provide powerful, consistent stopping power

With that in mind, you could be forgiven for thinking that the Reaction Pro is an out and out, lightweight XC focused aluminium race hardtail filling the same niche – and price point – as Giant’s XTC. But drill down on the details and it quickly becomes apparent that this bike shares the same aluminium frame as the £1,149 Attention SL hardtail that we tested back in the summer of 2022.

To bring you up to speed, we had mixed feelings about that bike. Yes it was well finished and had a stellar build kit, but the sizing and geometry both felt very dated. With the same frame pitched against three hardtails with a definite XC focus, where headline weights and long, fast-paced rides are near the top of the design brief, would the Reaction Pro make more sense? Before we answer that question, let’s take a closer look at the bike.

The Reaction Pro is offered in two colours; the stealthy black finish that we have on test and a sparkling Switchblue ’n’ Black. The frame has a clean, minimalist finish, without the visual bulk of some aluminium frames. Its sleek silhouette accentuated by the slender 27.2mm diameter seatpost – a rare sight now, as are the traditional quick release rear dropouts with 135mm hub spacing. In that respect the frame shows its age, which makes it even more surprising to see that it has a flat mount standard for the rear brake, something that only recently arrived on mountain bikes.

With five frame sizes available, Cube has taken a similar approach to Trek and designed the size small around 27.5in wheels, with the four larger bikes all benefiting from the improved roll over of the bigger 29in wheel. It’s a sound move as the lengthy 447mm chainstays on this XL are replicated on all of the 29in wheel options and would be way too long for smaller riders. And while size-specific chainstay lengths are starting to appear on trail hardtails, they are still a rare sight on hardtails from mainstream brands.

And while the chainstays are long, reach measurements are short. Jump on the Cube straight after riding the Giant and although both are marked as XL frame sizes, the difference in fit is remarkable. With the Giant there’s potential to down size, but with a reach a measurement that’s actually shorter than the chainstay length, you’ll definitely want to upsize on the Cube to try and improve the fit. On the plus side, the Cube has good standover clearance and a nice low BB height.

Suspension

Although cosmetically very similar, the RockShox Judy fork fitted to the Reaction Pro is built around a different chassis to the forks on the Trek and Scott. Cube has mirrored the rear end of the frame in the fork, with quick release dropouts and narrower 100mm hub spacing.

With the slimmer stature, the Judy fork on the Cube had noticeably less tyre clearance around the arch, and we were reminded of this when the rain arrived and we had to squeeze a front fender into the available space.

So for year-round UK riding, the quick release Judy is definitely a compromise.

Cube has equipped the Judy fork with a handlebar mounted remote, this time from RockShox itself. The PopLoc lever is plasticky and takes more effort to activate than Scott’s bespoke RideLoc remote, and as a result we used it much less frequently.

Components

If you’re hunting down a bike that’s packed full of quality hardware, then the Reaction Pro will certainly stand out on the showroom floor. It’s a full house of Shimano, with a mix of  12-speed Deore and XT for the drivetrain, including the stout two-piece Shimano chainset. There’s also a genuine Shimano chain, which is a real plus point as it helps provide slick shifting and a quiet life, even in wet and filthy riding conditions.

The Shimano XT brakes are certainly the standout component here, and although we had zero complaints with the lower tier Shimano brakes on the other three bikes, the XT’s offer easier adjustment and slightly more power. Performance was in fact faultless, with none of the wandering bite point issues that are a common complaint with Shimano’s premium brakes.

In fact, the only fly in the ointment are the cheaper resin-pad-specific rotors – a small compromise on an otherwise well thought through specification.

Performance

There’s a refinement to the alloy tubing of the Reaction Pro that gives it a ride quality that’s every bit as stealthy as its looks. Cables rattling inside the frame seems to be a common complaint on many bikes, including the Trek X-Caliber 8, but it’s simply not the case here.

With the shortest seat tube in test, there’s plenty of that slimline 27.2mm seatpost exposed, promising added compliance, especially when paired with Cube’s well-padded saddle. So the Cube provides a comfortable, resilient and quiet ride, with the only audible distraction coming from the wheezing damper in the Judy fork when pushing on hard through root-infested singletrack.

So the ride quality of the frame is up there with the best of the bunch, but the fit and geometry of the Cube really hold back performance. The long chainstays when combined with the short reach gives a very forward weight bias to the riding position, which is most noticeable when out of the saddle in steep terrain, up and down.

Yes, the 70mm stem certainly sharpens the steering up, but the seated fit is just way too short for an XL which makes it hard to feel efficient and comfortable when on a high mileage ride. A longer stem could help with the overall fit but would further compromise the handling and weight distribution, especially on the descents.

One simple option that would make the Cube better would be to fit a wider handlebar, as the stock 720mm bar simply compounds the cramped fit. The Cube lock-on grips, though, are spot on.

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