Surly were one of the original players in the plus-sized world

Surly were one of the original players in the plus-sized world and are still pushing all kinds of fat wheels and tires in their range. The Dirt Wizard is currently the chunkiest, heaviest, and most aggressive 27.5+ tire I have used to date. 

The Dirt Wizard is only available in a 3.0" width for 27.5" and 29", and there's also a 26" version in 2.75" and 3.0". The tubeless compatible, folding bead tire uses a single 48a durometer rubber compound, with a 60tpi casing that has added nylon sidewall protection. All that rubber comes at a price, and for $90 USD / €94.95 EUR the Dirt Wizard better have some tricks up its sleeve.

Design and Performance 

I had given up on plus-bikes for the kind of riding I do; they had some notable advantages, but were always too flimsy, prone to punctures, and I could never find anything that I preferred over swapping to 29" wheels with an aggressive/heavy set of tires. At the beginning of plus, most brands wanted to offset the added weight and rolling resistance of the bigger volume tires by using very low profile tread and lightweight casings to make tires around 800g. 

The theory was this: more volume = lower pressures, lower pressures and more surface area = more grip. But, to counter that, many plus tires had a shallow tread, which equaled less grip, a light carcass that gave more chance of puncturing and less stability, which meant increasing pressures to get the right stability and puncture resistance. This leaves you back at square one, where I always wanted to try the added benefits of the plus size but combined with the existing benefits of the thicker casing and aggressive tread. 

The downside of that combination is added weight, but there are riders who want plus-size grip and value stability and puncture resistance over weight savings, and there's also a whole new breed of plus-sized eMTB's that deserve tougher rubber. 

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