Boyd Eternity Hubs

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mdeth1313
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by mdeth1313

Anyone have thoughts on these? My first was the price is too high. You can get a set of extralite hubs for the same cost or less (580 usd).

http://www.boydcycling.com/eternity-hub-set/
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sugarkane
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by sugarkane

So a SET of extralites is lighter than the rear one by 40g and extralites have wider flange spacing ( 42.5mm ctf for the front and 42/19mm for the rear.. ) and cheaper

mimason
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by mimason

What are the flange diameters on the Extralights? Seems like we would need to do some math to determine which hubs build up stiffer. The Boyd's 'appear' well built and some of the design features are very cool...super wide bearings, drag reduction, nice weather sealing etc... I've never seen or ridden either but maybe they are much better just not lighter. No skin in the game though.

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F45
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by F45

Super wide front flange spacing isn't that important to me for a carbon rim build. The wheel is already stiff with 16 spokes and the usual flange spacing so why do I need 20 spokes with super wide spacing?

I haven't held these hubs but I do know the rear looks weenie with that thin center section. Wish he would have put a phat center in there, would have looked boss.

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WMW
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by WMW

mdeth1313 wrote:Anyone have thoughts on these?


They were supposed to be available last spring, but then they weren't. Don't know if anything has changed, but the old design didn't make sense to me.

Specifically the only thing supporting the right side of the hub is the freehub. Primarily the little inboard freehub bearing. This seems like a poor design for stiffness and bearing longevity. But like I said, it might have changed (this is from last March).

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coachboyd
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by coachboyd

Hey guys,

Thanks for the mentions.
The primary focus of the hub was for stiffness, stability, and lowering the rolling resistance. Weight obviously was somewhat of a concern, but not the primary focus.

That is why we did one piece, end to end axles (your fork and rear dropouts actually mount on the axles, not on end caps) and why there is two axles in the rear hub. This allows us to spread the load bearings out as far as possible, and also gives a system where only two of the four bearings spin when you are pedaling.

We did go through a design revision from when we announced the hubs last March. The outer axle (the green one in the picture posted) was aluminum, but we now have a carbon fiber tube press fit into the hub shell. Going to the carbon made a good difference in stiffness and strength. The freehub body is held securely in place by the hub shell instead of butting up against it. . .and so the load bearings are spaced at 105mm apart vs traditional hubs where there are 50-65mm apart.

We did test the strength of this on the road and in a lab environment. We took multiple wheels and put them on a testing jig. The jig loads the wheel with 85kg of weight and a drum spins underneath with a bump hitting the wheel every revolution of the drum. The wheel will spin both straight up and rocking back and forth. This basically simulates riding and then sprinting over cobbles. The tests last for 3,000km (which is just over 3 days of continuous running). We had multiple wheels go through this testing, and each wheel went through two rounds (for a total of 6,000km on the jig).

In terms of bearing longevity, the two left bearings in the freehub body (the blue bearings in the picture) only spin when you are coasting (maybe 5-8% of time spent riding depending on where you live). The two red bearings are supported as far out as we can, so you don't have an axle rocking back and forth inside the bearing. Most of the time when a bearing goes bad in a hub, it's the bearing inside the hub shell on the right side of the hub. That is because that bearing sits right in the middle of the axle, and there can be a lot of torsional forces on the axle. We aimed to eliminate that with this design.

Thanks again for the discussion, and let me know if there's any other questions.
http://www.boydcycling.com The Handcrafted Revolution

coachboyd
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by coachboyd

sugarkane wrote:So a SET of extralites is lighter than the rear one by 40g and extralites have wider flange spacing ( 42.5mm ctf for the front and 42/19mm for the rear.. ) and cheaper


I do want to point out that in regards to flange spacing, the Extralites are measuring from the center of the hub to the outside of the flange. We are measure from the center of the hub to the center of the flange.

I don't want to take anything away from their hubs, as they are very sweet!. . .but the flange measurement is measured in different manners.
http://www.boydcycling.com The Handcrafted Revolution

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WMW
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by WMW

coachboyd wrote:We did go through a design revision from when we announced the hubs last March. The outer axle (the green one in the picture posted) was aluminum, but we now have a carbon fiber tube press fit into the hub shell. Going to the carbon made a good difference in stiffness and strength. The freehub body is held securely in place by the hub shell instead of butting up against it. . .and so the load bearings are spaced at 105mm apart vs traditional hubs where there are 50-65mm apart.


Thanks for chiming in Boyd! Good to hear that you did a lot of testing.

How is the freehub held securely in place by the hubshell? Do you mean that there is a press fit on the carbon extension, or something else?

Also, if the arrangement is the same as in the diagram above, the hubshell is still supported by the freehub. The large outer bearing supports the freehub but not the hubshell directly. And the fact that the freehub bearings only turn while coasting is good for reducing drag, but static load capacities of bearings are lower than dynamic.

If you've thoroughly tested though and found no issues, that is what matters the most.
formerly rruff...

coachboyd
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by coachboyd

Yes, the carbon axle is press fit into the hub shell. It's a pretty hard press fit, but would be removable if you tapped it from the other side.

The freehub is supported by this carbon axle/tube If you didn't have the main axle, bearings, and end caps in place there is no play between the freehub and the hub shell. The hub does rely on load being placed to the freehub body, but because the freehub body is mounted and held securely by the hub shell, the freehub body essentially becomes an extension of the hub shell.

A good way to look at it would be you could remove the freehub body from most other hubs out there and still ride the back wheel (not pedaling, but it'd still be a rideable system). With this, we rely on the freehub body to extend the hub shell and spread the load. There would be no way to ride the rear wheel with the freehub body removed.

The testing that was done was to make sure the wheel held up to any type of riding that somebody could do. Bearing life gets tested the good old fashioned way. . .ride lots and in all weather conditions. I'd be lying if I said we haven't burned through any bearings, but a lot of it has to do when we were dialing in tolerances on axle length and supporting the bearings. It's amazing how fast you can destroy a bearing if it's side loaded!! However, in all of the testing on all the hubs. . .the two in the freehub that mount on the carbon tube have never gone bad. Not saying that it never could, just we have had really good results with them.
http://www.boydcycling.com The Handcrafted Revolution

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