Radial lacing on a back wheel

[Chris S]

I've heard that you can't have radial lacing on a back wheel because it can't transmit torque. What exactly does this mean? I can't see a radially laced back wheel just spinning on the spot.

 

[mickle]

On a wheel with crossed spokes the spokes are aligned to transmit drive forced at close to 90 degrees to the direction of rotation. Opposing spokes counter these forces. So the chain pulls the hub around and the spokes are pulled directly by the hub flange. The heads of spokes in a radial wheel can, under pedalling forces, move fractionally in the flange and this movement will eventually damage the holes. Also, as torque is applied to a radial wheel the spokes all wind up and the overall tension of the wheel increases sharply. A crossed spoke pulls through lots of material (the distance from the hole to the edge of the flange) whereas a radial spoke pulls through a thin band of material. It's the flange that gives way in a radial wheel failure and it ain't pretty.

I don't think i explained that very well but I just woke up so.

You don't see radially spoked hub or disk brake wheels for the same reason.

 

[fossyant]

It's quite a bad idea. What Mickle says. On the front you can get away with it if the hub is robust enough with custom built. Many factory wheels have used it.

It's not mechanically good, simple. Trend or not.

 

[GilesM]

What Mickle writes is correct, in very simple terms, the hub will twist within the wheel, initial result, not so much of the force you put into the pedals will be transferred to making you go forwards, and after a short while, the wheel will collapse. I used to use a radially spoked wheel on the front for racing on the track, and I sometimes used the same wheel for hill climbs, but not much use for normal riding, very rigid, and not really designed for your average road surface.

 

[Globalti]

Good explanation there from MIckle. But a really stiff radial front wheel helps a bike to handle positively, as long as there's a decent tyre, not pumped up too hard. Both my road bikes have radial fronts and they don't punish me.

 

[raleighnut]

The Roval rear wheel on my TT bike is half radial half 2 cross (on the drive side)

 

[User33236]

So the Campagnolo G3 spoke arrangement... how does that work, or not as the case may be?

 

[Smokin Joe]

The hub

So the Campagnolo G3 spoke arrangement... how does that work, or not as the case may be?

Torque transfer, if the crossed spokes are on the non drive side.

 

[mickle]

Don't get me wrong, I love a radial front wheel, but only on a rim brake equipped bike.