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Thursday, March 21, 2013

MOUNTAIN BIKE WEEK - SPECIALIZED ROVAL WHEELSET REVIEW

The following review came to us via Bicycling News and it is a review of a 29'er Carbon Mountain Bike Wheelset that I highlighted during our wheel sale a couple of weeks ago.

Specialized’s Innovative Roval Control 29 Carbon Wheels, Tested
To make these tubeless wheels stronger, Specialized did the unthinkable—they removed the bead hook.

ByMike Yozell
 
Forgive the cliché, but Specialized has just about re-invented the mountain bike wheel—well, at least one small but critical aspect of it. The lightweight, reasonably priced Roval Control 29 Carbon’s rim has an innovative design that makes it stronger and less susceptible to damage when you smash into rocks on the trail, or land awkwardly off a jump. The design works so well that it might just change the way all wheels are made.

For decades, wheels used a similar profile: A continuous lip—the bead hook—at the upper edge of the rim held the tire’s bead. That connection kept the tire in place, even if the fit was less than perfect. But that hook became less important as tubeless tires came into fashion, and required better-fitting tires: To prevent air from leaking, manufactures use more exact tolerances. The hook still provides surface area onto which sealant can adhere, but it’s no longer needed to keep the tire in place—as long as the tire has a strong bead and properly fits the rim, it should remain in place once it’s snapped on.

And, the bead hook created some problems for wheel designers. Significantly, it created a weak spot on the rim—one that was particularly susceptible on carbon models. The lip, which extends in from the rim wall, acted like a lever when you smacked your wheel against a rock or hard surface. Hit the ground with enough force and the rim’s wall could fold over. When this happened on an aluminum rim, riders or their mechanics could easily straighten the wheel back out; do it to a carbon rim and your $1,000 wheel could crack and splinter, rendering it unrideable and unfixable.

Specialized Roval Carbon Control 29
A wide center channel helps the tire seal against the rim wall, even without a bead hook. (Courtesy)
The solution eventually became obvious to Specialized: Borrow established technologies from automotive and motorcycle tires—which are also tubeless—and ditch the bead hook. By getting rid of it, Specialized removed one potential weakness. Without the hook, the company was also able to thicken the rim wall, making it even stronger.

With the hook gone, engineers set out to tighten the seal between rim and tire, necessary because the sealant had less material to cling to, making it easier for air to escape. The fix was simple but effective: the new wheel has a wider inner shoulder, which gives the tire’s bead more surface area to seal against. There’s also a more robust rim strip that prevents sealant from leaking through the rim’s spoke holes. Together, these improvements keep the tire from blowing off the rim once it’s inflated.

In theory, that makes sense. But what happens when you hammer the wheels on rocky East Coast trails for months? To find out, I spent the winter testing these hoops on my local singletrack—trails so technical and rocky they’ve made a few veteran riders consider giving up the sport. To make sure the wheels were practical for a range of users—not just those content to buy tires from Specialized—I mounted six tire models, both standard and tubeless compatible. While some manufacturers don’t recommend using non-tubeless tires without tubes, I’ve had good luck and for this test chose tires that have worked well on other Roval models.

I expected that the wheels would be good, but I also counted on experiencing a few hiccups. Perhaps certain tires wouldn’t hold air, or seat properly, or maybe some would burp air on hard hits. Remarkably, I experienced zero issues. Even mounting tires was painless—the Roval’s deep rim trough created space to easily slip on a tire, while the ramped shoulder helped direct the tire up against the rim, creating a tight seal when it’s inflated. I injected sealant just as I would with any other tubeless-ready setup.

During the test, several snowstorms blew threw the region. Snow filled in the gaps between some smaller rocks, turning sections that normally require slower speeds and precise handling into wide-open speedways. To maintain traction, I dropped tire pressure down as low as 16 psi on one ride. Even with so little air, the tires remained stuck to the rims and didn’t burp. After the snow melted, the trails bared their teeth again and I continued to run low pressure (about 18-22 psi), but I never flatted and the tires never flinched. After weeks of hard riding, the rims emerged without cracks or dents. I can’t say that for many other carbon rims I’ve tested on our tough trails.

The unique rim profile is just one of many well-executed design elements. These Control 29 Carbon wheels have 32 front and rear spokes—more than on some similar models—which boost stiffness and increase durability. The hubs roll on sealed cartridge bearings and are based on proven internals used in the popular 250-series models from DT Swiss. The wheels come with end caps that work with most standard axle sizes, though you’ll need to purchase a separate adapter to use these wheels on bikes with 20mm front thru-axles. The rear hub even can be converted to accept SRAM’s XX1 rear cassette.

Specialized Roval Carbon Control Axel and Bearings
The wheels come with end caps that fit most axle standards. (Mike Yozell)
Few details escaped the attention of Specialized designers. The wheels themselves are hand built with DT Revolution spokes and Pro-Lock nipples. The robust rim strip never slipped or developed wrinkles, even after repeated tire changes. The Rovals also use valves with removable cores, an upgrade from the previous versions that allows you to add fresh sealant without peeling off the tire.

Although the Control 29 Carbon wheels are targeted at the XC crowd, they’re also suitable for trail riders willing to pony up for a lightweight wheel. We rode these models hard, in unforgiving conditions, and they withstood the abuse. At 1,587 grams per set, they’re only slightly heavier than the company’s premier race model, the Control SL Carbon. With a price of $1,200, these wheels are not cheap, but their low weight and durability make them a great value.
 
If you would like to see these wheelsets for yourself or to pick up a set stop by the shop.  We have them on display and I am contemplating using a set for a build I am pondering.  If you are a serious Mountain Biker who is weight conscience and needs reliability I would think this wheelset would do great things for your ride!
 
Tom's Pro Bike Service
3687 Walden Avenue
Lancaster, New York 14086
F: (716)651-0858

3 comments:

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  2. That's very nice post about bicycle wheelsets it's very informative thanks for sharing.

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  3. Hi this one is great and is really a good post. I think it will help me a lot in the related stuff and is very much useful for me. Very well written I appreciate & must say good job.. carbon fiber bike frame

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