For the past 15 years, True Precision Components’ Stealth hubs have been silently propelling BMX racers to countless victories. The hubs offered a magical combination of both completely silent freewheeling and instant engagement thanks to the use of a one-way bearing. Recently though, it was time for a change. That change was Box Components purchasing the rights to produce their own version of Stealth, now part of the Box One product line.

BOX Components Stealth Hub internals

While the Stealth hubs are no longer produced by True Precision Components, Box claims that “all of the materials, construction, tolerances, and internal construction remains the same.” That means they use the same German-Made one-way bearing to offer silent, instant engagement. How does that differ from something like an Onyx hub? Where Onyx uses a sprag clutch bearing, Box claims that since the one-way bearing has moving rollers inside, it offers less drag, decreased wear, and faster engagement than a sprag clutch bearing.

The internals of the hubs are the same, so what’s changed? On the outside, all of the hub shells have been reshaped with slimmer profiles to drop 15-25g and they have angle flanges for better spoke alignment. The mountain bike hubs gain a lighter axle configuration, and the BMX hubs now have 10mm axles with bolts that use an 8mm allen key.

BOX Components Stealth Hub BMX

More importantly, the BMX hubs now use a driver that accepts a standard Shimano cog and lockring instead of the proprietary cog and driver from the TPC hubs.

BOX Components Stealth Hub MTB

Like seemingly all hubs that use a one-way bearing or sprag clutch, the weight of the rear hub is on the heavy side at 475g for the MTB hub and 315g for the BMX hub. Of course that weight is at the center of the wheel, but it’s still something to consider.

BOX Components Stealth Hub front

BOX Components Stealth Hub MTB rear

To be eventually sold as individual mountain bike hubs, you are only able to “make a reservation” to purchase them. Once the ability to preorder them is open, you’ll be given a notification. The 6 bolt mountain bike hubs will be offered in 28 or 32h options with Boost 148×12/110x15mm spacing and will have options for Shimano or SRAM XD freehubs. Pricing is set at $149.99 for the front and $349.99 for the rear.

The BMX hubs are available for purchase now, for the same price per hub.

stealthhubs.com

13 COMMENTS

  1. If Onyx’s and Box’s hubs both have instant engagement, how can one be faster than the other? I think the answer is that the engagement is instant, but that the instant part of the engagement is not a complete, full, totally solid engagement.

    • @Tim,
      Not sure either although examining the types might give an idea.
      Sprag bearings have a bunch of ‘sprags’ which work basically like pawls in a normal hub except there are no ‘teeth’ – instead the sprag pushes against the outer shell to lock in place.
      Roller clutch bearings use ‘ramps’ to push a roller against the outer shell to lock it into place.

      Couldn’t tell ya which is better or why. Roller clutch seems like it would be cheaper based on having fewer and simpler parts but who knows.

      • One might be better or worse than the other, but for me the soft engagement means I wouldn’t buy either of them without testing it first and comparing it to a more conventional hub. I mean, if rapid engagement is such a benefit, then these silent hubs with “instant” (asterisk soft) engagement are not as beneficial as they seem at first glance.

    • I think you have just hit on the metaphysical “Schrodinger’s hub”: Is the hub engaged? Does observing it engaging alter the nature of the engagement? Can I get fries with that? Sorry, I am such a dork

    • I don’t believe a roller clutch can be “instant”.
      A sprag clutch is as instant as possible, as it often uses a spring to stand the sprags upright ready to lock up immediately. They only move backwards enough to allow the outer ring to slip by, and are therefore have slightly more drag.
      A roller clutch, on the other hand, uses rollers and ramps. So unless there’s a spring holding the rollers forward (ready to lock), there will have to be some displacement of the roller moving up the ramp before it locks. However, because the roller is moving down the ramp, away from the outer ring, it would produce less drag.

  2. On his site, Don Pardo (I assume it’s him) has an overview of the pros and cons of roller and sprag clutch hubs. He mentions both True Precision and Onyx, but only comments on early generation versions of the hubs. Back when True Precision apparently custom made their roller bearings and when Onyx had a fair amount of “elasticity” or windup.

    Both hubs have changed and presumably improved since those initial reviews, but I think his general comments still apply:

    “A roller is a small diameter, leading to a narrow “line” contact between the roller and the inner/outer bores where it runs. A sprag can have a larger/gentler radius and so makes a “wide line” contact, which distributes the load better and so is less likely to, say, dent the inner or outer bores.

    “The number of rollers you can fit is limited by the diameter of the roller. You can fit more sprags in the same space because they are narrower. Using more sprags means the same load is carried by more “lines”, which further increases the load capacity.”

    With rollers and sprags inside the hub body instead of squeezed into the cassette body, rollers can be larger diameter, but sprags can still be made with larger virtual diameters.

    The BOX mtb rear hub is $110 cheaper and more than 60 grams heavier than the Onyx. But the Onyx is available now (mine were shipped pretty much the same day. Yes, I might be biased.) and it is also available in many different sizes: 135 QR, bolt on, and 10 & 12mm thru ; and 142, 148, 150, and 157 12mm thru, compared to the 148-15 (15 or 12? Typo?) of the BOX. Onyx also has Campy, XD-R and Microspline cassette splines available in addition to the regular XD and Hyperglide.

  3. Built up a wheelset with Onyx Vespers this season for my new mtb. Rolled the dice and based my purchase solely on reviews of Onyx, their customer service, and the intrigue of rolling silent. I was coming off a set of DT’s with the 52 star tooth, so have been enjoying pretty rapid engagement already. Well, let me tell you, I rolled the dice and won! Onyx are a game changer. I’m not a hammer and weigh 185lbs and the engagement is absolutely 110% instant. Out of turns, the power is ON. Over rocks and half pedals in gardens, it’s like a crow bar lifting me over everything. AND the JOY of rolling silent is something I look forward to every single ride, especially with my friends with their angry bees stinking up the forest with that annoying sound; it makes me ride faster to get away from it! The silence is real. All I hear is my tires in the dirt, my bike’s suspension and wind. It’s pretty incredible. No friction whatsoever and the rear wheel spins like a front wheel. I feel my bike has a motor when coasting and oh the silence. It’s soulful. 1800 miles this season on my new mtb (custom build Orbea Occam) and not one issue. I’m all for any hub that rolls silent no matter how it’s achieved. You won’t be sorry, but sadly, you won’t be able to stand the sound of pawls anymore – it’s akin to hearing a dentist’s drill.

  4. That’s why I was so excited to see Shimano come out with the Sylence(?) freehub a while back. Shimano quality/availability and silent. Too bad it never made it to market.

  5. Is there any torque limit on these and similar hubs? I seem to remember that was the big problem with roller type clutches, the spreading force inside the cassette body could wreck the mechanical system. At 180lbs, I’ve had a few problems out in the woods (not on the seriously reputable stuff, but on second tier standard pawl type), and getting stuck out there with a whack freehub is a serious drag.

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