Unless you have spent the last few years growing a beard like Billy Gibbons and hiding out from “The Man” somewhere on the Appalachian Trail, you can’t fail to have noticed that plus size tyres are flavour du jour. 650b+, 29+, full fat, take your pick. Heck, even road tyres are getting their chubby on and going fat in the name of all road/gravel/gnarmac (delete as your marketing manager dictates). Leading the charge, Surly created something of a minor storm when they introduced the Krampus, a rigid bike designed for simply having fun built around the at time proprietary technology of 50mm rims and 3 inch tyres with tall sidewalls. Mated with their Knard tyres, the new set up offered the advantages of improved traction and increased comfort through being able to run higher volume tyres at a lower pressure. For bike-packers in particular, despite the added weight, the advantages were pretty clear. Pretty soon, even the big manufacturers started to embrace the plus size revolution (or should that be evolution?) The Knard is a great tyre in the right conditions but show it mud and even die hard users will accept that they have limits. What was needed was a tyre that embraced the slop and muck and which didn’t need Zen like skills to stay upright when attacking the trail in typical British conditions. Enter the Dirt Wizard.
The route to market has been something of a long winded affair. Delivery dates came and went, much to the chagrin of eager consumers, as R&D continued until Surly had a product they were truly happy with. When a pair of the 120Tpi Dirt Wizard tyres arrived at my door, I nearly did a double take. Now I knew how Harry Potter felt when he found a Horcrux! Tearing apart the box, I immediately set about fitting them to a pair of 50mm rims. This was a breeze, the tyres seating securely on the bead of the rim. Pumping them up to around 12 psi, I was ready to rock. The tread design is reminiscent of a downhill tyre, the pronounced central blocks coupling with tall side knobs to create an aggressive profile designed for eking out the last sliver of grip that can be the difference between nailing it and being nailed.
To be honest, first ride out, I was a little bit ‘meh!’ Coming from several months of riding on 4.8 inch fat bike tyres, even 3 inch tyres look and feel a little on the slim side. They aren’t what you would call quiet on tarmac. Rolling resistance is more than acceptable for such a burly tyre and while they aren’t quite a match for a Surly Knard or a Maxxis Chronicle in this department they are surprisingly fast rolling for a tyre so chunky. A couple of extra psi in the tyres does make a difference though when riding to and from the trails.
On loose and loamy trails, they gripped tenaciously
Off road, these puppies really come alive and deliver on the promise of a plus size tyre that can handle the mud. Leaning hard into corners on the front wheel, I came to appreciate the extra grip and feeling of security that the Dirt Wizards delivered. On loose and loamy trails, they gripped tenaciously. In mud and slop, they outperformed my go to 29 tyres, Schwalbe Hans Dampfs, finding grip where the Schwalbes would be outgunned. Don’t get me wrong, I very much rate the Schwalbes but for outright grip, you can’t change the laws of physics! On loose, boulder strewn, rocky trails, the tread pattern engenders confidence and have more than once made the difference between going for it and taking the easier option. The additional volume combined with the ability to run the tyres at a lower pressure adds up to creating a genuinely comfortable ride experience, even on a hardtail. There is none of the un-damped bounce that you can experience with fat bike tyres but you definitely experience some of the benefits. If you come from an XC background, you’ll probably balk at the added heft compared to your fag paper thin, semi slick race day tyres, but then you would be missing the point. If you love steep and technical climbs, the extra grip that the Dirt Wizards seem to find can make the difference between cleaning that technical section which you have always struggled with and having to get off and walk. Intuitively, lighter tyres and wheels climb better but if you are struggling for traction, all you will find is that you are pushing a slightly lighter bike. These may not have the out and out speed of a race bike set up but for the majority of users, does it really matter?
Overall: They may not be the lightest or the fastest tyres out there but if you just love riding your bike for fun, these will put a big grin on your face. There’s definitely something to plus size tyres.
For more info have a look at the Ison website