well, perhaps I can see what you're getting at conceptually, but I certainly haven't given in to any thoughts of trying to actually calculate the math/physics... I just noticed the problem when I rode it, and then futzing around in the work stand afterwards I could simply pinch/squeeze one side of the wheel rim against the opposite fork leg with my fingers and deflect the shit out of it.
I've had other wheels where it was obviously a case of play in the hub/axle that allowed the wheel to flop off-axis, but this definitely appeared to be flex in the spoke/rim assembly. Whatever it was, I get much less of the same deflection using the same fork with my 808 (which, ironically, does have a little play in the hub, but overall the wheel resists flexing out of plane as much). It just seemed pretty intuitive to me that if you visualize the Hed without the fairing, you're left with an 18-spoke wheel on a relatively shallow rim... which would surprise nobody if you said that was flexy. The fairing just gives the appearance of a deep rim so 18 spokes doesn't seem like so few. Additional spokes like the stallion build would've obviously helped, how much I don't know.
And besides the number of spokes and stiffness of the rim itself, if you look at the Zipp vs Hed construction the other factor at play is the triangulation of the spokes in the lateral plane... the Hed has a flangeless hub and of course the spokes are also longer as a function of the shallower rim, so the spokes brace the wheel from a much shallower angle than the Zipps when viewed from the front. Seems like that has to play a role, doesn't it? Maybe it has less to do with the supposed stiffness of the rim itself and is more a function of the length of the spokes?
I've built a couple wheels before so I realize the whole is greater than just the sum of the parts, so maybe I just had one that didn't add up for some odd reason (spoke tension?) and my rationalizations about the design are misplaced, but I swear the difference was pretty obvious holding them in your hands side by side.
I've had other wheels where it was obviously a case of play in the hub/axle that allowed the wheel to flop off-axis, but this definitely appeared to be flex in the spoke/rim assembly. Whatever it was, I get much less of the same deflection using the same fork with my 808 (which, ironically, does have a little play in the hub, but overall the wheel resists flexing out of plane as much). It just seemed pretty intuitive to me that if you visualize the Hed without the fairing, you're left with an 18-spoke wheel on a relatively shallow rim... which would surprise nobody if you said that was flexy. The fairing just gives the appearance of a deep rim so 18 spokes doesn't seem like so few. Additional spokes like the stallion build would've obviously helped, how much I don't know.
And besides the number of spokes and stiffness of the rim itself, if you look at the Zipp vs Hed construction the other factor at play is the triangulation of the spokes in the lateral plane... the Hed has a flangeless hub and of course the spokes are also longer as a function of the shallower rim, so the spokes brace the wheel from a much shallower angle than the Zipps when viewed from the front. Seems like that has to play a role, doesn't it? Maybe it has less to do with the supposed stiffness of the rim itself and is more a function of the length of the spokes?
I've built a couple wheels before so I realize the whole is greater than just the sum of the parts, so maybe I just had one that didn't add up for some odd reason (spoke tension?) and my rationalizations about the design are misplaced, but I swear the difference was pretty obvious holding them in your hands side by side.
Last edited by:
OneGoodLeg: Feb 7, 12 14:30