Ron Ruff wrote:
> On May 10, 6:36�am, "joseph.santanie...@[EMAIL PROTECTED]
"
> <joseph.santanie...@[EMAIL PROTECTED]
> wrote:
>> If that is the case, it doesn't matter which side the spokes are on.
>> Any "pull" spoke transfers torque to the rim, whichever side it is on.
>> So then it would make sense to have radial on the DS, not the NDS.
>> That way the shorter spoke and resulting angle helps make up for the
>> more inboard placement of the DS flange.
>
> It would help a little... but think about what you've done to the NDS
> spokes. Instead of 19mm and 36mm spacing, you'd get maybe 21mm and
> 36mm (just guessing). If you put 120kg in the DS, then the NDS would
> be 70kg... and these are the only spokes transfering torque. Combine a
> high torque load with the radial and side loads, and it won't take
> much to make the pu****ng spokes go slack.
>
>> This is totally unscientific and anecdotal, but I just took my light
>> wheels (28h, 2x DS, radial NDS, narrow AC hub flanges) for a short
>> test, and did some purposefully agressive side to side sprints. It
>> seems the wheel only have the occasional flop when I lean the bike to
>> the right, and the rims feels like it flexes in toward the NDS.
>
> You are very perceptive! This is the side that will buckle first,
> since the NDS tension is lower and the spokes are at more of an angle.
it's not so much a tension thing as a spoke angle thing. and it's the
angle of the /drive side/ spokes that causes it. basically, the closer
the drive side spoke angle is to perpendicular, the more any applied
load stretches those spokes, hence the non-drive side can slack more
easily.
> You can demonstrate this easily by taking the wheel out and pressing
> on the edges of the rim, while the axle rests on a solid surface. The
> wheel will "boing" with lower force when you press towards the NDS.
indeed. see above.
>
>> The
>> flanges mean there is essentially no dish, so the only real difference
>> between each side is spoke length and thus angle. The rim does not
>> seem to flop toward the DS. That makes sense because the NDS is radial
>> and is in better position to resist.
>
> There is dish. Probably ~19mm DS and 28mm NDS. This is the main
> difference. Oddly, if the spacing (dish) was greater, you'd think the
> lateral stability situation would get worse... but it actually
> improves. A narrow spacing improves the tension balance, but this is
> only an issue if you have spokes going slack from radial loads... for
> all other loads it makes things worse. Narrow flanges reduce the
> lateral stiffness a lot, since this goes up exponentially with bracing
> angle, and they also reduce the load required to make the wheel
> buckle.
|
