Test: With a width of 2.1″ and a slightly rolling profile, the WTB Nano 2,1 tire is somewhere in the border area between cross-country and oversized gravel tires. We put the border crosser to the test.
The WTB Nano tire should certainly be known to one or the other reader - but probably more as a 40mm wide gravel tire. As the Nano 40c, it enjoys great popularity because it strikes a successful balance between rolling resistance, off-road suitability and weight. With the WTB Nano 2.1, however, we tested the 2,1″ wide version for 650b wheels. It is officially classified as an XC tire by WTB, but with the characteristics inherited from its 40mm brother and the moderate width, it also does very well on a Road-Plus or Gravel-Plus bike.
The WTB Nano 2.1 is available for 29″ and 27,5″ wheels and in three different versions. In addition to the inexpensive Comp version, there is also a special tubeless version for WTB's own TCS tubeless technology and a light race version. In our test, we took a pair of 650b tires as a race version and mounted them on a Rondo Ruut gravel bike, which belongs to the new ranks of Gravel+ bikes.
WTB Nano 2.1 – Light weight and easy assembly
Our two test tires weighed in at 578g and 586g respectively, which is about mid-range for tires in this class. In our case, they were mounted tubeless on a light Industry9 Trail 24h wheelset. Even if the Nanos are not explicitly tubeless tires, it worked without any problems: Although both tires could be pulled onto the rim very easily, the fit was nice and tight and the system was sealed immediately using a simple floor pump and approx. 50ml of sealant each . It couldn't be easier with a hose!
The structure of the WTB Nano is quite interesting: The profile is of course rather reserved overall in order not to increase the rolling resistance unnecessarily, which would probably be a knockout criterion for the vast majority of potential buyers. The center of the tread is slightly raised - this reduces the contact area with a corresponding tire pressure. Sure, that costs grip, but it rolls along quite smoothly despite the width and the differences to the classic 40mm gravel tire are small. If you then go off-road, you can increase the contact area by releasing the tire pressure. On the 23mm (internal width) I9 rim of our test system, the Nano 2.1 is almost exactly 54mm wide and thus corresponds to the factory specifications.
WTB Nano 2.1 – The right air pressure is crucial
As with any new tyre, it is important to get a feel for the first few meters and to find the sweet spot for the air pressure. On asphalt and gravel, this was between 2,4 and 2,5 bar for our taste, as soon as we went off-road, we lowered it to 2 bar at the front and 2,2 bar at the rear. The rolling resistance on forest highways and on the road is, as we expected, very good for a tire in this class. Yes, it can't quite keep up with a gravel tire and it's noticeably harder to move forward - but for an XC tire the Nano does extremely well. In damp, wet and greasy conditions on the road, the rubber compound knew how to convince: It hardly hardened even at low temperatures around freezing point and always offered us reliable grip.
But of course, for fast laps on asphalt, WTB has other tires in its range - the Nano 2,1 is at home off-road and that's where it had to prove itself in our case, of course. Here it was noticeable that the right air pressure is absolutely crucial for the performance of the tire, more so than with most other tires. If you are under too much pressure here, the Nano tends to slip away, especially in wet conditions, and gives little security, as it often suddenly loses its grip.
However, the WTB tire shows a completely different face when you let off some air: This allows it to exploit its width advantages and claws into the ground much better. Not only does the level of grip increase overall, the tire is above all much more forgiving. At the limit in damp and wet conditions, it announces the loss of grip quite early on and with a little sensitivity you quickly know where the limit is. Trail excursions are also great fun.
During our testing period, we had no issues with air loss, burping, or even flat feet.
