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NAHBS 2015: New Boyd Cycling hubs take stiffness, smoothness to Eternity and beyond!

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The new Boyd Cycling Eternity hubs push bearings and flanges wider than ever to create a super stiff wheel, and the unique stacked axle system helps it roll smoother by effectively disengaging two of the four bearings when pedaling.

Founder Boyd Johnson says the hubs offer the widest flange spacing out there, especially at the front, where there’s 80mm from center to center of the flanges. Out back, he says most hubs have between 50mm and 55mm between rear flanges, but the Eternity hub pushes that to 56.1mm from flange center to center. The driveside flange is pushed to 18.1mm from hub centerline to flange center, which Boyd says is the widest that can be used on a modern 11-speed drivetrain. And it’s all optimized for both stiffness and tension with a traditional lacing pattern.

Those wider flanges create a wider base, improving triangulation. That means a stiffer “pyramid” peaking at the rim, which translates to less rim deflection under cornering loads. But that’s just part of what makes a stiffer wheel, so let’s have a look inside and see what else makes them special…

BOYD ETERNITY FRONT HUB AXLE COMPARISON

On both front and rear, the hubs use what’s essentially a thru-axle design, but it still clamps with a skewer. On both wheels, the dropouts are resting on the axle…there are no end caps. This makes the axle as wide as possible, running from end to end, and the bearings are pressed on top and set very wide to make the system a lot stiffer. Shown above is the Boyd Eternity axle on the top compared to a traditional front wheel axle.

BOYD ETERNITY FRONT HUB AXLE NEXT TO SHELL

“Another benefit to that is when we do the preload over the axle, it makes it harder for water to penetrate the system,” Boyd said. “Which prolongs the life of the bearings and the hubs.”

The image above shows the axle with preload caps snugged up to the bearings. They thread into place to adjust the preload, then a set screw locks them into position. Bearing width on the front hub is 74mm center to center.

Boyd: “The rear hub has 49% of the tension on the non-drive side, making it virtually even from side to side. That’s with traditional, double cross 24 spokes putting 12 on each side of the wheel. Once you get above 59kg of force per side, it’s enough to keep the spoke nipples from loosening, and going much above that doesn’t do much to increase overall wheel stiffness.

“If a wheel builder wants to do “triplet” lacing (8 on non-drive, 16 on drive side), we could make a new shell with an even wider flange spacing that’s optimized for that lacing pattern, but I’d caution that with just eight spokes on the outside, if one broke for some reason, it could ruin the ride home.”

BOYD ETERNITY HUB REAR AXLE SCHEMATIC

The rear hub gets even more creative with its axle system. There’s still a single axle (yellow) that runs all the way through the hub into the dropouts, just like the front, except this one’s a leggy 143.75mm. And the main bearings (red) sit on that axle, pushes as far out as possible.

“On the rear, the bearing placement we have is by far the widest in the industry,” says Boyd. “And when we talk about bearings, there are two types in the rear: the freehub bearings, which just make the freehub body spin, and the hub bearings that actually support the wheel on the axle. We made it so the freehub body sits on the hub shell rather than on the axle. So when you’re pedaling, both the freehub body and hub shell spin at exactly the same rate, so the freehub bearings (blue) are not spinning, which cuts bearing drag in half when pedaling. The freehub body becomes an extension of the hub shell, and so the load is spread 105mm apart.”

BOYD ETERNITY HUB FREEHUB BODY SUB-AXLE

The Outer Axle (green) threads into the hub shell, and the freehub body rests on that. Boyd says the design allows for quick, easy freehub body removal for cleaning and greasing -about 30 seconds- as all driveside bearings are pressed into the FH body and pull off as a unit.

They use a titanium freehub body, which isn’t a new concept, but the way these are made is. Instead of machining the part from raw billet, these are injection molded, which yields a FH body that’s about 99% done when it pops out of the mold, requiring minimal post-production finishing before tapping in the bearings and installing it. Basically, they inject a liquid 6/4 titanium slurry into the mold, cool it through a proprietary process that the supplier won’t even fully divulge to Boyd, then pop it out and put everything together.

FREEHUB PAWL PATTERN

Inside the freehub is an A/B, two-step pawl mechanism that engages four pawls at a time, but only one notch on each pawl. A second notch is clocked to engage at the next half step, effectively doubling the number of engagement points. The result is a 5.6º engagement thanks the A-B, two-step pawl.

The pawls and driver ring are made of hardened, heat-treated A2 steel, which is very hard and very durable. Those parts are then electroplated to reduce friction by creating a super smooth, durable coating on both surfaces, then they’re lubricated with a special grease from NixFrixShun (one of our favorite chain lubes).

The front hub is a claimed 100g, rear is 224g. The complete hubs shown above are preproduction with an temporary alloy freehub body, but weights are with a titanium one.

There’s not a single washer or spacer anywhere in the hub…only the parts that actually serve a purpose, which means easier servicing, but more importantly, fewer things to be loose, out of tolerance or otherwise diminish performance. They’re 100% made, designed, engineered and manufactured in the U.S. He found a CNC manufacturing partner in Pennsylvania, and Boyd Cycling is based in Greenville, SC.

Retail is $580 for the hubset, available aftermarket and as complete wheels, starting to ship end of March.

Disc brake models are in development, and will be available with either these QR axles or a different, thru-axle specific design.

And the rear’s bracing angle and flange spacing will actually improve a bit with the move to disc brakes because, as Boyd explains, they have room to put disc brake mounts on this design already, but when you go to a 135mm rear spacing for disc brakes, there’s even more room to push the non-drive flange out. Look for the disc brake versions just before Eurobike in August.

BoydCycling.com

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Graham
9 years ago

This looks great and the design is solid but building a front wheel 2x or obviously 3x provides increased stiffness over radial.

Timbo
Timbo
9 years ago

“So when you’re pedaling, both the freehub body and hub shell spin at exactly the same rate, so the freehub bearings (blue) are not spinning”

Huh? Don’t they always spin at the same rate under load? Otherwise aren’t we talking about internal gearing? The picture makes sense and shows a cool design, but that sentence is a bit confusing.

Derek
Derek
9 years ago

With most conventional hubs, the bearings connect the axle to the freehub body. The axle is always stationary, so when you’re pedaling there is relative motion between the axle and the freehub body so they bearings are rotating.

In this design, the freehub bearings are between the hubshell and the freehub. When you’re pedaling, there is no relative motion between the two so the bearings are not rotating. Well the whole bearing is spinning but the inner and outer races are just spinning together.

diggy
diggy
9 years ago

Not sure I understand the design on the drive side. The main loads bearings are pressed into the freehub, which means the loadpath is through the freehub??

My inner mechanical engineers is telling me that is a bad idea, having structural load path through a rotating ratcheting joint.

Mike
Mike
9 years ago

@Timbo-the freehub body and the hub shell are always spinning at the same rate under load but most hubs have the freehub bearings ride on the axle not the hub shell. Seeing as the axle is fixed to the frame the freehub bearings are spinning along with the hub shell bearings.

Mike
Mike
9 years ago

Looks like Derek beat me to it, should have refreshed the page before typing!

Souleur
Souleur
9 years ago

interesting…for sure

overall, i like the concepts, I am careful about everything with new stuff tho

tongue in cheek: next, they will narrow it all back down again for more aerodynamic profile

the physics definitely make sense, and flanges do as well, as well as the bearings load…not sure its $580 better, but that is the price for new goodies

I will say, the engagement system looks a bit iffy to me, i can see after time that little notch being loaded heavily with time

Francisco
Francisco
9 years ago

@diggy, I thought the same too at first, but looking closer, the load passes staight from DS ‘red’ bearing to its neighbouring ‘blue’ bearing. The freehub, being supported on both ends, effectively becomes an extension of the hub shell and the ‘red’ axis. I cannot foretell if the design will be durable in practice, but the concept seems sound.

rememberswhen
rememberswhen
9 years ago

works somewhat like what we use to call a freewheel. before most of you had your first strider 😉

Ced G.
Ced G.
9 years ago

interesting! These may wind up at the heart of my next build…

Kurtis
Kurtis
9 years ago

18.1mm center-to-flange is decent for a rear DS, however with straight pull you can go way wider – I’ve even seen them out past 19mm for Shimano 11s.

bikermark
bikermark
9 years ago

“not sure its $580 better, but that is the price for new goodies”

That MSRP is competitive if people are cross shopping with White Industries, Chris King, DT Swiss, and Dura Ace 9000. Glad to see they aren’t taking the shortcut to low weight for the rear hub (an aluminum freehub body).

Mike T.
Mike T.
9 years ago

That all looks & sounds interesting. I’m going to have to re-read and digest.

pfs
pfs
9 years ago

Pretty sure they just copied the sram X0 hubs for that engagement system. Been in place for a few years now. Cool idea though.

larsv
larsv
9 years ago

Nice design. 🙂

Looks a bit like the Easton Echo hubs http://brimages.bikeboardmedia.netdna-cdn.com/wp-content/uploads/2013/07/Echo-Hub.jpg, but taking it one step further:

Boyd has managed to put the right side wheel bearing outside of the free hub bearings. Cool

shafty
shafty
9 years ago

That green axle/sleeve thing looks to be a potential point of failure as it’s only possible to support it on one end. I’d be interested to see what the clearance between that sleeve and the axle is on the far end. There’s also nothing locating the hubshell side of the freehub. The only thing holding it in position is the pressfit of the most outboard bearing.

Relying on tolerances to solve a design can work, and in this case the price certainly reflects that mindset, but that means you’ve got to take great care of these. While not all that similar in design, these remind me a lot of Gokiso hubs. Those are in another league entirely though.

Bolivia
Bolivia
9 years ago

those poor frame builders… the only news coming from their show is about new products.

tom
tom
9 years ago

I too am interested to see if these design works over the long term. Alchemy had problems with their cantilevered hub shell extension, which is basically what what the green sleeve looks like. The join between it and the hubshell is going to be under a lot of stress, and the threads will tend to focus the stress in one spot.

Novakki
Novakki
9 years ago

So…tall flanges? Doesn’t look that way. Google e-thirteen-TRS+-Hubs

Boyd Johnson
9 years ago

Hey guys!

Great discussion here. I do want to say that with the hub shell extention, its not just an extension out of the hub shell. It’s a full on axle that has a telescoping end and threads into the hub shell. This creates the strongest possible design as any possible fatigue point is in the middle part of the axle (which sees the least amount of stress). For any possible failure an axle would have to break in the middle, and that doesn’t happen.

thesteve4761
thesteve4761
9 years ago

If this is true: “They’re 100% made, designed, engineered and manufactured in the U.S.”, their $580 price is not terribly bad, provided the quality is there, but it sure is more than you’d expect from Boyd.

Robert W
Robert W
9 years ago

The design looks good, but the aesthetic quality is not there for $600 hubs.

18spokes
18spokes
9 years ago

Injection molded titanium. In other words, pot metal. Maybe that’s strong enough tho, time will tell.

Cheese
Cheese
9 years ago

Not pot metal, 18, not die cast, they’re metal injection molded. This means that they require several steps between popping them out of the mold and tapping in the bearings, though, and they don’t achieve 100% density.

http://www.protolabs.com/metal-injection-molding/

MM
MM
9 years ago

$600 for these, or $600 for White Industries. I know where my money is going.

clive de sousa
9 years ago

Got a see them up close and I think Boyd is really onto something here. I am all in on the design, I feel like there is good reason to pick these hubs over anything else on the market if you are looking for performance.

PS
PS
9 years ago

Very cool. Glad to see another US product. Time will tell how they work.
I am not interested enough for a purchase. COMPETITIVE or COMPARABLE Pricing? VERY DIFFERENT words… for 20.00 more you have options of very reputable hub sets US made that have been in the game a LONG time..Not sure that is competition yet.I hope they do well and totally understand the pricing, glad to see another US bike part. Now how about some frame builders from the show and not new bike parts!

Darryl
Darryl
9 years ago

Shimano’s original freehub is exactly this.
That’s why they called it a free hub. The freehub body screws into the hub shell and effectively becomes part of it allowing the wheel bearing to be pushed all the way to the outside.

This was done to prevent the then common rear axle breakage when cassette bodies went wider to accommodate 7 and then 8 speeds.

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