Do-It-All Tires
By James Sharp

Tires are like shoes for your bike. Go to your closet, how many shoes do you have? If I asked you why so many, you would probably tell me that different shoes are for different circumstances. In my closet I have a pair of lightweight hikers, some running shoes, my winter cycling shoes, my summer cycling shoes, some sandals, a pair of slip-on Jungle Mocs, and a couple pair of dress shoes. Why? Well, the running shoes are for running, the hiking shoes are for day hikes and backpacking and when it is wet out. The Jungle Mocs are for day–in-day-out wear. The rest are pretty self-explanatory. What about tires? How many tires are in your collection? I’ve got semi-slicks, fat knobbies, road tires, and more. These are all different “shoes” for my bike. If the terrain is going to be smooth road, skinny slick tires are the order of the day. If rocky, rooty trail is on the menu, then a mountain bike shod with wide knobbies fit the bill. No matter the terrain, there are tires that work well on it. Likewise, no matter the tire, there is a terrain where it will work perfectly. The hard part is making a tire that works well in a variety of terrain. Today’s trail bike is the mutation of the original go anywhere mountain bike. It isn’t meant for racing or freeriding, but something in between. This type of bike requires tires that are as versatile as the bike is, nothing “race only”, but not too heavy, either. I recently spent some time on the Continental Vertical Pro and the Geax Sturdy. Both are wide tires full of knobs and both are the tubeless versions.

Vertical UST
Sturdy UST

Continental Vertical UST
At 2.3 inches wide, the Vertical is the widest tire that Continental makes in a UST version, making it an ideal candidate for the above-mentioned trail bike. The tire consists of pentagonal shaped knobs, utilizing Continentals EndlessEdge knob design and pattern. The idea behind EndlessEdge is based on three things, knob shape, knob placement and knob height. All three of these vary with the Vertical. The side knobs are shaped and placed to give good bite and consistent transition as the tire leans into a corner. Knobs are placed in clumps such that straight line traction is optimized regardless of the angle of attack. This means that even if you are climbing an off camber rooty trail, you will have an edge to dig and grab hold of the trail so you can move forward. The center lugs are arranged in such a way as to minimize the rolling resistance of the tire.

How well does all that translate into good, go-anywhere traction? As a friend of mine would say, "they’re sick, they hook up". These tires really don’t care if it is muddy or dry they sink their knobs into the dirt and don’t let go. They don’t seem to pack up with mud too bad, due to the taper that the lugs have. I found them to be a great mud tire, just be sure that you have enough clearance for what mud they do pick up.

Now I’m sure that you are asking yourself; "Is there anything wrong with these, they seem great!" They are great, with one caveat...weight. Continental claims that the UST version weighs 750g. Ours came in at 800.7g. In two tires, that is almost a quarter pound of rotating weight, and that’s just the discrepancy. They aren’t light, though the non-UST versions are claimed at 590-698g, depending on the casing and whether it has a Kevlar or steel bead. This means that you probably won’t be using it as a race tire, though.

Summary: The Continental Vertical UST is a tough-as nails tire that will see you through just about any terrain. It is kind of narrow for a 2.3, but that can be good news if you are planning on using it on a bike without much clearance, or in the mud.

Geax Sturdy UST
I’m just going to come right out and say it... the Sturdy is a HUGE tire. It is much taller than the Continental and, though listed at 2.25 inches, wider as well. This is a tire for bikes that are skirting the edge between the aforementioned trail bike and the longer travel free-ride bike. It has big square knobs that are arrainged in a direction specific orientation. However, rather than the usual front/rear directionality these are traction/speed directional, more on that later. Geax has given the Sturdy an Aramid 3D Compound casing, this means that they put chopped Aramid fibers into the rubber, making the stronger and longer lasting than a plain rubber tire would. They also claim that it makes the tires lighter. If so, I’d hate to see the weight without the Aramid! Claimed weight for the UST version is 850g. Ouch, you say? Ours weighed in at a whapping 925.4g! That’s a hair over 2 pounds per tire. Tube versions of the tires are claimed to weigh between 630 and 730g, depending on size and bead.

Originally we mounted the tires in the ‘speed’ direction. This worked out great for the front, but, contrary to all appearances, it made the Sturdy a horrible rear tire regardless of the pressure. Run the ‘traction’ direction, however, made the tire pretty good. I wouldn’t go so far as great, but definitely pretty good, that is, on trails here in Western Oregon. On a trip to various places in Utah, this tire came into it’s own. It loves rocky terrain. It loves going fast on rocky terrain. Basically, the rockier, the better, as far the Sturdy is concerned. It’s big volume and big knobs latch onto the rock where a more fragile tire would fail.

Summary: The Geax Sturdy is one of the biggest, toughest, longest lasting tubeless tires on the market. As such it could be a good choice for more aggressive, or heavier, riders. However, I started this article by talking about a go-anywhere-do-anything type of riding. As a front tire, this is a good one, but there are better choices out there for a rear tire.

A word on UST: You’ll notice that both of the tires reviewed here are UST-compatible tires. This is done for a couple of reasons, first, often times tires advertised aren’t available in tubeless form so it is nice to highlight those that are. Second, tubeless tires have the same tread pattern as their tubed counterparts, so from a behavioral standpoint the two will ride similar in similar terrains, i.e. if a tubeless tire excels in loam, the tubed version of the same tire will, more often than not, excel in loam, provided that the two tires are the same size. Finally, from a reviewers perspective it makes sense in that there are fewer flats and the tires are just as easy to swap out, if not easier. Every tire reviewed here went on without tire levers and inflated with a floor pump. Personally, I see their popularity rising as more and more tread designs and sizes are available as tubeless tires.

James Sharp is a contributing editor for GearReview.com specializing in mountain biking.

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