I’ve been riding my 29er for almost a year now and one of the things that was frustrating initially was the lack of component variety available. It was kinda like being a Mac guy in a PC world but thankfully it’s getting easier every day to find 29er versions of most MTB components and accessories.
The WTB Vulpine has been around since 2007 but the 29er version I tested didn’t come out until the next year in 2008. WTB claims to have produced the world’s first 29er tire in 1999 and the Vulpine is said to be the first semi-slick 29er tire. I’m not sure why it took 9 years to produce a semi-slick 29er tire but I’m glad the Vulpine is available now – I’ve always been a big fan of low rolling resistance tires like this one!
If you’re not familiar with the concept of a semi-slick bike tire, the idea is that you can remove the deeper knobs at the center of the tread pattern to cut down on resistance while leaving the side knobs to grip in the corners. Semi-slick tires aren’t ideal for all trail conditions, especially wet situations where you need increased traction. But for those who like to ride fast over hardpack, a semi-slick tire like the Vulpine really makes sense. WTB also positions the 26-inch version of the Vulpine as a good choice for the pump track.
The diagram below from WTB shows the anatomy of a tire and is helpful in understanding some of the terms used to describe mountain bike tires. The Vulpine 29er tire features an Aramid bead which is lighter than a conventional wire bead and super durable (point of fact: Kevlar is a para-aramid compound that can stop bullets). Since this is a racing tire (as opposed to a “weekend warrior” or “enthusiast” tire), it uses WTB’s lightweight casing and DNA rubber compound to keep the weight as low as possible (just 650g).
The Vulpine 29er is a 50/52 tire on the GMS scale and to be honest I wasn’t too familiar with this measurement before writing this review. Sheldon Brown’s website has a good explanation of WTB’s tire sizing system but it basically goes like this: the top number is the width (in mm) of the casing while the bottom number is the width of the tread at a specific tire pressure (see diagram above). At 50/52, the Vulpine tread is pretty narrow – just barely wider than the casing itself. All other things being equal, a narrower tire will be faster but may tend to cut into muddy sections rather than floating on top, for example.
The Vulpine 29er is not front/rear specific so you can run the tires front, back, or both. These tires feature a directional tread pattern so be sure to mount them facing forward. Installation was completely standard and I got a nice tight fit on my Easton XC One wheels.
I’ve actually been riding these tires exclusively for a couple months now and I’m surprised at how versatile they are, even in conditions not traditionally recommended for semi-slick tires. Many riders may prefer to run a Vulpine up front and a grippier tire in back (like the WTB Wolverine or Prowler SL) for climbing. I found the Vulpines to be fairly capable climbers front and back but it’s really all about technique. Over slick roots the Vulpines spun out occasionally but no more than usual for me.
The Vulpines are designed for speed and on fast, flowy trails these are the best 29er tires I’ve ever used thanks to in part to aggressive, low profile knobs. One of the biggest complaints you’ll hear about 29ers is that the big wheels take more power starting from a stop so it’s important to select a lightweight tire like the Vulpine. The improvement over my previous tires was actually pretty noticeable when transitioning from braking to mashing the pedals, even though we’re only talking about a few dozen grams weight reduction.
Despite the elongated outside knobs I found the Vulpines weren’t great at cornering on trails with moderate leaf coverage or loose dirt over hardpack. On a recent group ride I found myself leaving other riders behind in the straights, only to have them right on my tail coming out of sharp turns where I nearly lost it. If I were to improve this tire I’d try elongating the side knobs a bit to more deeply penetrate leaves and loose soil. Of course that would add weight to the tire which is clearly a trade-off – glad I’m not a bike tire designer.
For those who ride fast, XC-style trails, the WTB Vulpine 29ers are an awesome choice. They’re lightweight and versatile enough to bring out some of the best a 29er mountain bike has to offer. Get one or two for your machine and you’ll see what I mean!
Thanks to WTB for providing these mountain bike tires for review.