Schwalbe G-One Ultrabite

The Schwalbe G-One Ultrabite is the most aggressive in Schwalbe's gravel line, and features larger knobbles not only the other G-Ones but most other gravel tyres as well. This results in excellent grip but increased rolling resistance, meaning they're best for those who venture way off the beaten path – not those thrashing dry, hardpack surfaces at speed.

Available with black, tan or these limited-edition olive green sidewalls, the G-One Ultrabite is unapologetically focused on offroad use, blurring the lines between the G-one gravel and X-One cyclocross ranges even further.

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In this 38mm width the G-One Ultrabite has a claimed weight of 530g, but RoadCC's scales of truth say 571g. Compare this to the G-One Bite's measured weight – 455g – and it's apparent the Ultrabite not only gains grip, but also a significant amount of mass.

As with many modern gravel tyres, the Ultrabite is tubeless compatible. This is particularly useful as the terrain gets harsher and lower pressures become preferable, as the last thing you want is a pinch flat in the middle of a ride.

Physically getting them on the wheels in both tubed and tubeless scenarios proves easy, but getting them seated is a different matter. If I had to do it again I'd lubricate the sidewalls first – I hear washing up liquid does the trick.

My unlubed attempts on two different wheelsets left me with the Schwalbe writing still tucked inside the rim and, despite inflating them to 70psi (the maximum rating of both the tyres and my offroad rims), they failed to pop out and seat correctly. In the end I gave up and went on a rather wobbly ride, but even this didn't force the beads into place.

> Fitting tubeless tyres – learn how with this simple guide

On a set of 19mm (internal width) rims the G-One measures up accurately at 38mm. On 21mm rims it came up slightly wider at 39.5mm.

On the road the Ultrabite's high weight does impact performance, and it feels sluggish to accelerate. Its speed isn't helped by the added rolling resistance of that tread pattern, either (see Bicycle Rolling Resistance's test for the sciencey numbers).

Grip on the loose

Despite what seems like a pretty negative review so far, the Ultrabite is a good tyre – at least offroad. The large shoulder tread makes muddy corners easier, and the added rear traction really comes in handy. The Ultrabite is perfect if you take your gravel bike to slippy fields or even muddy singletrack.

The ADDIX Speedgrip compound is borrowed from Schwalbe's mountain bike tyres, and gives excellent grip and good durability. I've covered about 600km on mixed terrain – including rocks, tarmac and of course gravel – with no sign of wear or punctures.     

While the Ultrabite can turn a bog-standard gravel bike into a cyclocross or XC bike rival, the tyre's main undoing for me is just how good the other G-One variants are. The G-One Allround, for example, copes with surprisingly loose and slippy terrain, yet rolls far better on asphalt and hardpack; surfaces often found in even the gnarliest gravel rides.

> 26 of the best gravel bike tyres — get the right go-anywhere rubber

At £41.99, the Ultrabite is well priced. Plenty of gravel tyres will set you back more, and the similarly aggressive Teravail Rutland is £60. There are competitive alternatives, though. Specialized's Rhombus Pro 2Bliss is comparable at £42, and almost exactly the same weight, but then it's wider – 42mm.

Overall, the G-One Ultrabite is a very capable offroad tyre that can take a gravel bike into territory more associated with mountain bikes. It comes at the cost of extra weight and rolling resistance, though, and that's not great for speed across hardpack paths or roads. Therefore, these tyres are best suited for riders who spend most of their time on the slippy stuff and want the maximum grip possible.

Verdict

Super grippy tyres best for those staying off roads and hard paths completely