Vitus Nucleus 29 VR

Head over to the Vitus website and you could be forgiven for thinking that you’re seeing double. You’re not, it’s simply that Vitus offers the Nucleus VR with either 27.5in wheels or 29in wheels. Both options are the exact same price and both come with very similar wheel size appropriate build kits, that include different fork travel, different tyre sizes and different gearing. 

• Best hardtail mountain bikes: classic trail-shredding machines

Regardless of your preferred wheel size both options also use bespoke alloy frame designs, where Vitus has sensibly used the wheel size split to offer subtly different size ranges. The 27.5in wheel bikes run from S to XL, the 29ers from M to XL. The idea being shorter riders will benefit most for the smaller wheels, as they need more bum/tyre clearance.

The bigger wheels give this Vitus plenty of flow and roll-over

To keep the test fresh we opted for the Nucleus 29 VR, as we know from experience that bigger wheels roll over bumps better, especially when you have zero rear suspension, so they keep the rider fresher too. 

The lightweight alloy 29er frame has all the features you’d expect on a modern trail hardtail. A tapered headtube, internal routing for a dropper and ISCG tabs on the bottom bracket shell for fitting a chain device. And even though the seat tube has a slight kink in it, to help tuck the bigger 29in rear wheel in nice and tight to keep the chainstays short, there’s still plenty of seat post insertion, so getting the saddle well out of the way for shredding is easy. 

We’d like to see shorter seat tube lengths of the Nucleus 29 VR

Suspension

One of the big differences between the 29in Nucleus VR and the 27.5in bike is that it has 20mm less fork travel, so 100mm vs 120mm. Both bikes get the Suntour XCR 32 LO-R which is air-sprung and easily adapted to different rider weights. The fork also has externally adjustable rebound damping, but that’s not enough to put it level pegged with the fork on the Carrera, as this fork is really sticky. Maybe the bushings were too tight, but even with all of the dials wound wide open the fork was slow to react to impacts and very harsh. 

The Nucleus 29 VR runs a 100mm travel fork but the action was sticky and harsh

And while you could take one look at the 9mm quick release dropouts and assume the fork wouldn’t be stiff enough, Vitus is the only brand in this category to use a tapered steerer tube, so fork stiffness isn’t a problem. 

The bar, stem and lock-on grips are all well chosen and great to see on a bike at this price

Components

With a Nukeproof riser bar and 50mm Vitus stem the cockpit on the Nucleus is totally sorted – the lock-on grips a real bonus in wet conditions. The Maxxis Ardent tyres also offer a good compromise between rolling speed and traction, and will definitely dig in better in loose conditions than the lower profile Ikon tyres on the Polygon. We were impressed by the Clarks brakes too, as they were more powerful than the Tektros and have a light lever action just like the Shimanos.

The hydraulic Clarks disc brakes are powerful with a light action too

In fact, the only question mark over the build kit is the 8-speed Box drivetrain. Yes, you read that right, the Vitus only has 8 gears. The cogs on the SunRace cassette run from 11-42t so the range isn’t shocking, but the jumps between some of the gears is really pronounced. Also the shift action isn’t as light or as precise as that of the Shimano drivetrains found elsewhere in this test. 

• Best mountain bikes under £1000: reviewed and rated by experts

Performance

We had high hopes for the 29in version of the entry-level Nucleus VR but sadly, it did not deliver. The congested action of the 100mm travel Suntour fork meant that the ride was harsher than it really should have been. So while the overall shape of the frame is sound, if not cutting edge, we always felt like we had to hold back, for fear of taking an absolute beating.

With only eight gears on the Vitus there are big jumps between the ratios

And being the lightest bike in class, the Nucleus 29 VR should have made light work of the climbs, but again it was hamstrung by the specification. The larger jumps in the 8-speed Box drivetrain often left us spinning a gear that was too easy or grinding in a gear that was too hard. 

Tubeless-ready WTB rims and Maxxis Ardent tyres make for a great wheelset