Names and faces to bikes

im pretty sure that this is a back wheel using radial spoke pattern
but for some reason unknown to me you cant do it on both sides?
although how does that work with a flip flop hub?
someone explain please...

post was a few pages back, but i didn't come across a good answer so i thought i'd chime in.

in general, when forces are distributed to the rim, through the hub, you are relying on the spokes.

Now imagine twisting a string around a pencil. the string doesn't sick out straight from the center of the pencil (as in the radial wheels), but sticks out at a tangent to the edge of the pencil. this is because that is the most efficient way to move the string. if you radially laced a rear hub, it would attempt to twist with each pedal stroke to position the spokes at a tangent, like the string/pencil. At the first few degrees of this motion, the hub has a huge advantage over the spokes, and so this action would place an enormous amount of force/tension on the hub/spokes.

As you move closer to a tangent, the hub loses a lot of it's advantage, and the spokes need less tension to hold the hub from spinning inside the rim. this is why when you build a drive wheel, you cross the spokes in opposite directions in a pattern such that the spokes are all coming off at a tangent.

Front wheels never experience forces delivered through the hub, so they are ok with radially laced wheels.

you will never see a radially laced wheel which has a disc brake though, and this is for the same reason.

The crossing pattern has an affect on this property as well.