Riding a bike down a rough mountain hillside can be pretty sketchy. Even modern full-squish bikes with disc brakes still don't remove all the various trail features that threaten your general well-being and intactness. Knobby tires were a game changer over the balloon tires the boys back in Marin, CA were rocking on their clunkers. We reckon there's still a big contingent of people out there who like to throw down and get rowdy.One way of doing that is mixing in a little new school with the old school. The Rock Razor blends the advantages of stout side cornering knobs with a shaved-down minimal center tread. This design puts a premium on fast, allowing riders to carry heaps of speed when bombing fall line down the hill, flick their way through tight corners, and carve around berms like a banking fighter jet. You'd better bring your A-game with this tire because if things go wrong, it's probably too late to do anything about it. Braking is not this tire's strong suit. But if your victory speeches contain lines like "Go for broke" (speaking of which, this tire isn't cheap) and "Let it all hang out," then this tire might warrant some consideration.
Schwalbe Rock Razor 2.35 PaceStar EVO Review
Compare prices at 2 resellers Pros: Rails corners, FAST, low rolling resistance
Cons: Expensive, wear quickly, scary for intermediates
Our Analysis and Test Results
Familiarity can help a rider's confidence. It's fun to ride a local trail you've lapped hundreds of times. You know every corner and rock. You know when you can ease up on the brakes and carry speed and when you need to pull things back in a little. On familiar ground, we loved the Rock Razor. The small center tread made us feel like we could go just a little faster. The big side knobs allowed us to lean into corners just a little further than usual. When the scenery changed and we found ourselves on unfamiliar ground, we were a little overwhelmed at first.
Like many semi-slick designs, this tire simply doesn't have the chops to take a big, bike stopping bite when things get going a little to fast on unfamiliar trails. When a corner came up faster than we anticipated, we couldn't fully commit. Staying upright made the tire feel a bit skatey as the big shoulder knobs never had a chance to dig deep. This tire can punish the technique of a timid rider. If you're racing, we recommend pre-riding the course to minimize surprises. When your synapses are firing and your reflexes are lightning fast, this tire is the one that can keep up.
Conventional wisdom might lead one to take extra caution when dealing with sharp objects. The Rock Razor defies convention and rewards those that are unafraid to press harder and dig deeper. An aggressive approach may not necessarily be easy to commit to if you're new to this breed of semi-slick tire. Visually, the low-profile center tread consisting of small, evenly-spaced knobs might not instill much confidence in the rider used to seeing big, tall knobs in the rearview, but holding back is not the answer and doing so you're bound to get cut. Being based in Lake Tahoe, as much as we love biking, we love skiing just as much.
This tire acts just like a ski, whereby it runs fast and smooth in a straight line and then WHAM! Roll it on edge and it hooks up to slice a turn. Much like an intermediate skier will never fully optimize a ski by skidding turns instead of carving them, a timid biker may never reap the benefits of the Razor's giant side knobs by remaining more upright in favor of laying the bike over into a turn. To reap the benefits of this tire, you've got to commit. Commit to the turn and tip the bike over like you mean it. Don't be afraid. As soon as those DH-sized shoulder lugs grab some dirt you'll be carving berms like Lindsey Vonn carves gates. Love this tire but can't afford the $92 price tag? Check out the Specialized Slaughter that is a fraction of the price, but equally adept at cornering.
What sets this tire apart from other semi-slick designs is that there is no question as to when those shoulder lugs are engaged. Compared to the competition, the difference in tread is much more defined.
Pedal traction was a bit of a mixed bag for the Rock Razor as it is highly condition dependent. Climbing in what we describe as loose-over-hard is not the tire's strong suit and the small center tread of this tire make it easy to spin-out when putting lots of force through the pedals such as during a steep climb. This is especially evident with hard efforts out of the saddle. Granted, spinning the rear tire using a standing climbing position is nothing unusual, and grip certainly increased when seated. However, sometimes standing is just necessary on super steep ascents and when it hasn't rained in quite some time, you may feel a bit of slippage instead of grippage. Expect the same from the Specialized Slaughter and to a lesser degree, with the WTB Trail Boss. Aside from durability issues, the Continental Trail King is a billygoat.
Extremely dry and sandy conditions allow the shoulder lugs to sink deep enough to provide sufficient traction. Basically, anytime those big side knobs are engaged it has good traction. The first few pedal strokes after coming around a corner when the bike still has a bit of a lean to it are impressive.
It almost goes without saying that anytime you get this tire on rock it has good traction. The small center tread is especially adept at taking rocks straight on and squeezing every last ounce of traction from them. Even if taken at an angle, the side knobs conform to the face of rocks rather than fold or slip.
Like the other semi-slick rear tires we selected for this review, braking performance probably won't seem overly impressive to those riders used to running bigger knobs in the rear. Alternating row height on the small crown tread knobs are used in the same way as on a dirt bike tire tread. This gives a little more bite that is especially noticeable when braking on very firm riding surfaces. By contrast, when testing in the deep loose pumice at Mammoth Mountain, we felt the monstrous side knobs probably aided in braking to a greater degree than the crown tread. Quite often at Mammoth our tires were nearly sunken to the rims in this unusual substrate and nothing short of big knobs could slow our descent with much efficacy. For this type of riding, the Michelin Wild Grip'r, WTB Convict, and Maxxis Assegai are well suited.
The Rock Razor needs a confident and precise pilot and it certainly benefits from being paired with an aggressive front tire like the Schwalbe Hans Dampf to increase overall braking traction. Less experienced or more cautious riders may feel a lack of braking control with this tire.
There's not much holding this tire back from picking up speed on a straight trajectory when you tip the bike downhill. The medium hardness of the tightly spaced, small center knobs allows the tire to turn over at a furious pace. This tire was a favorite among testers when ride days had a large uphill component on mostly hard packed surfaces like dirt roads or short pavement climbs. On these firmer surfaces, we could arrive at the top with enough gas in the tank for the fun part of riding downhill. The tread on the Michelin Wild Grip'r Advanced and Continental Trail King will hold them back by comparison. The Specialized Slaughter could keep pace, but the Rock Razor is also a rocketship; probably the fastest in our test.
We were pleasantly surprised at the lifespan of this tire. Our previous experience with Schwalbe tires had been that they're great performers but unfortunately weren't long for this world. Typically costing a premium, we usually saved these for race days. Training with them and riding on pavement seemed to severely limit their lifespan. After 100 miles, our tires showed minimal signs of wear. We chose the firmer PaceStar MTB race, all-mountain compound which we theorize increased the lifespan of this tire. Had we chosen the softer TrailStar compound like we did for the Schwalbe Hans Dampf that we ran up front, perhaps our experience would have been different.
The outside knobs held their shape well with little in the way of shearing off and slicing. Perhaps one benefit to this tire is that it doesn't perform much differently after it's slightly used than it does from the day you first install it on your bike. The sheer size of the side knobs will take a while to wear down, but we still wouldn't make a habit of skidding with the bike leaned over.
The Snakeskin sidewalls offered adequate protection from abrasion and survived the duration of our test without slicing or tearing. We did suffer a greater amount of flats with this tire on especially rough terrain, however, which left us feeling a bit unsupported by the tire's casing. If you desire a longer wearing tire, we recommend the Maxxis Aggressor, an Editors' Choice winner for rear tire. The Aggressor might not be as fast per se, but more rubber means more miles and the increased control you'll experience might actually translate to quicker times.
This tire has a very pliable feel and slipped onto our rims easily by hand. The Tubeless Easy Snakeskin sidewalls snapped into place on our rims the first try. We got plenty of practice with field-installation of this tire as we flatted more often than when running other tires.
If you love that feeling of leaning a bike waaaay over in a berm and rocketing out the exit then this tire will leave you whooping with joy as you pedal into the next one. You'd better be confident in your ability to carry serious speed into a turn because slowing down quickly isn't where this tire shines. Pick your apex right, drop that outside crank, and give in to gravity as the massive edge knobs achieve maximum bite. Try to fight the G-forces and stay upright through the turn and you'll be punished with an uneasy, unpredictable ride.
Though you can typically find this tire cheaper than sticker price, Schwalbe tires come at a premium. This $92 tire was the most expensive rear tire in our test by about 10 bucks. The PaceStar version we tested will likely wear a little longer than the softer TrailStar compound and at least in the rear, this compound seemed like a pretty good choice. Trailstar will also cost you a few extra bucks, closing in on the $100 mark. Despite the fact that longevity with this semi-slick exceeded our expectations, it's low-profile tread doesn't take much to become even lower-profile as the miles pile up.
If you've got the coin to spare, this tire rips in dry and fast conditions and would make an excellent enduro race day pick. If the course winds down the hillside with tons of turns and fast pedaling sections, this tire might just get you to the bottom ahead of the competition. Get off the brakes and let it roll. Loose dirt and mud will leave you wishing for a tire with a bit more bite down the center tread. We're reluctant to recommend this tire for exceptionally rough and rocky descents as we flatted in this type of terrain more with the Rock Razor than any other tire. The Super Gravity casing option (not tested) may be a better choice if this is the type of terrain you ride most often.
— Sean Cronin and Jeremy Benson