I want to know how big the bearings are. If they are the same as a standard hub the bearings would wear out really quickly and the hub wont be as stiff as it claims.
“Giant flanges give spokes more mechanical advantage on the rim, decreasing spoke tension and wind-up. The ultra-rigid carbon tube transfers driving torque from the drive side flange to the non drive side, reducing peak spoke tension on the drive side by a staggering 70%”
Huh? whoever wrote that hasn’t ever built a wheel.
i wouldn’t have thought the flanges have anything to do with it. drive side of the hub to the non drive side of the hub perhaps. the flanges just pull the spokes around.
Wire spokes work in tension, not compression. The rim is the limiting element for spoke tension, not the hub. Spoke tension should be as high (or close to as high) as the rim can bear (too-high tension will cause a rim to taco). A big diameter flange will reduce the length of spoke needed, but not the tension required to build a wheel that will “stand” (ie doesn’t go out of true). It’s more often than not too-little tension that causes spoke failure, especially at the bend (as the spoke compresses at/around bottom dead centre in rotation, if it’s not under enough tension the spoke will move a tiny bit in the flange hole and fatigue eventually). If a spoke head is set carefully and the spoke under adequate tension that shouldn’t happen for a long, long, long time, if ever. On a dished wheel with conventional lacing spoke tension will need to be somewhat higher on the drive side than the non-drive side. “Reducing spoke tension by a staggering 70% on the drive side” doesn’t make sense - it’s just more marketing bullshit like “ceramic balls are 25 times as round as steel balls” (there was a thread involving some spirited discussion about THAT a year or so ago).
I should switch to decaf. Need a wheel built? PM me.
I would have thought that given a strong enough rim, you could fail the hub flanges (C-Record, radial lacing), as the rim is in compression and only likely to fail by buckling, whereas the flanges are under tension.
That said, it’s probably more of a fatigue failure, rather than static overload.
Larger flanges will result in a larger bracing angle though, which will require less tension to pull the rim across as compared to a smaller flange. Not that this matters for a fixed hub as the flanges are symmetrical!
A larger diameter cylinder will have a higher polar moment of inertia (Jx), which will resist torsion better.
Jx = pi/2 * (Ro^4 - Ri^4)
So if you take a hub with a 20mm barrel vs an 80mm barrel and both have a wall thickness of 1mm, the difference in Jx is a factor of 71.
Yes, the Chub’s better at transmitting torque from the cog to the non driveside spokes without suffering from barrel windup, but I doubt it’s significant when compared to losses from the spokes, the tyre etc, plus the driveside has spokes too…You could take two hubs and lace all the DS spokes leading and all the NDS spokes trailing and compare those, but who’d be stupid enough to ride a wheel built like that?
“I would have thought that given a strong enough rim, you could fail the hub flanges (C-Record, radial lacing), as the rim is in compression and only likely to fail by buckling, whereas the flanges are under tension”
extremely unlikely with any modern hub unless it’s been fucked with in some way, like slotted badly to accommodate bladed spokes, then it’ll more likely be a fatigue failure.
“…Larger flanges will result in a larger bracing angle though…”
Not enough to make a material difference, see Jobst Brandt, Gerd Schraner and other wheelbuilding gurus on this point.
“…which will require less tension to pull the rim across as compared to a smaller flange”
not to any material degree, but that’s not the issue. My point is if you use “70% less tension etc etc” than you ‘normally’ would, the wheel will not stand. It will fail. It will fail quickly.
“Not that this matters for a fixed hub as the flanges are symmetrical!”
So the crap about “an incredible 70% less tension on the drive side” is even more stupid for a symmetrical track hub. (not all track hubs ARE symmetrical by the way, I have some Primatos that definitely aren’t).
I think that is the key point here.
There is no way on earth that you could reduce the standing tension by that much. the the rim would move independently of the hub.