When our surprise package showed up, we quickly weighed and photo’d Specialized’s new Ground Control mountain bike tires and mounted them up.
I’ve run them on our local trails, which consist of loose gravel over hardpack (as seen above), firm dirt and plenty of roots and log piles. I also raced them at the BURN 24 Hour in May, which started off a bit damp, dried out, then had some slick roots come morning, giving me a wide range of surface textures for the test.
How’d they perform? Jump past the break to see if they live up to their heritage…
The test pair we received was labeled 29×1.9. They measured in at just a hair over 1-7/8″ or 1.875″, so pretty close. This is mounted to a Stan’s NoTubes Crest rim, ridden on a Niner Jet 9.
Personally, I would have chosen a wider tire, but these things surprised me. The tread is fairly low-profile. Judging from the pic above, I’d peg the knobs about about 1/8″ tall.
The edge knobs have bolstered sides, which keep them firm all the way until you come off them. So, lean into a wide sweeping corner and they maintain a consistent grip until the angle gets too severe. Then they don’t. The knobs don’t carry far enough around the casing for aggressive leans. Once you bring the angle back up, they pick up traction again instantaneously.
They rolled fast in a straight line with no perceptible drag. Acceleration is as quick as you can put it out, and braking performance in a straight line is more than adequate. Braking in a hard corner is pretty good, they’ll hold for longer than some low profile tires before breaking loose.
The only issue I had was keeping air in them without a fair amount of sealant. Of course, my idea of a “fair amount” is the recommended two scoops. I usually skimp and do about one scoop’s worth to save weight, but this led to rather quick air loss. I had to add air on longer rides a couple of times. Once I added more sealant, they held air much better.
Speaking of air, because these were narrower, I ran them a few PSI higher than normal to keep them from feeling too squishy. On a couple of really hard, fast corners, they squirmed a bit too much for my liking, but that was usually when they had spilt some air (see above paragraph).
The new Ground Control tires should appeal to racers and weight weenies that don’t mind sacrificing a little on-the-edge cornering performance for an overall very fast, capable XC tire. They grabbed well on a wide variety of surfaces, wet and dry, and what little mud I did run through shed very, very quickly. I think a wider (2.1) version would work better for me and improve the squirm and cornering concerns I had with the 1.9.
