Tester: Eric McKeegan
Price: $90 (120 TPI version)
Plus size tires have mostly stuck to the “buncha small knobs” design brief. While this has been surprisingly effective, sometimes terrain and riding styles call for some big, sturdy knobs. The Surly Dirt Wizard answers that call with a mean-looking tread pattern and aggressive cornering knobs.
Looks don’t deceive here. This tire turns, brakes and climbs with authority. With a new rubber compound and tubeless bead, you can run low pressures for extremely effective grip. It’s been a revelation to lean my 29plus Trek Stache over and find abundant cornering grip, something that could be lacking on the stock tires.
The trade-off for all this wonderful wizardness? Weight. Even the not-that-sturdy 120 tpi tire weights 1,080 grams, which is approaching dual-ply DH tire territory. For reference, I haven’t had any problems, personally, but know a few riders who switched to the heavier (1,390 grams), sturdier and cheaper ($80) 60 tpi tires after tearing sidewalls on the 120 tpi. Surly’s other 29plus tire, the Gnard, is also well-known for being not-sturdy in the 120 tpi version.
Tire pressure is important with these tires, even more so than most plus size tires. Between the big cornering knobs, the width and the light casing, low pressures and grippy terrain can cause a ton of squirm if there isn’t enough pressure to support this tire. After dialing in the pressure (somewhere around 13 psi for me), I was happily trying to drag my bars around corners.
For all-around aggressive use, this is the best thing going for 29plus bikes. I’m most happy with one of these as a front tire and something lighter and faster as a rear. Even though the Dirt Wizard is often overkill for the type of riding I do most often on my 29plus bike, I’d rather have some shreddy-ness in reserve. There is also a 27.5×3 tire, currently in 60 tpi only.