Wheel building - Is this a dangerous pattern?

[PIGEON]

Right, a while ago I was just screwing around with an old wheel that I wasn't going to use anymore. I took it apart, painted the rim and spokes and when it was time to put it back together I didn't feel like lacing it up the way it was before. I had already built a couple of wheels before but it still takes me more time than I cared to spend on that wheel at that time. So I decided to try something different: all the spokes on the left flange are trailing and all the spokes on the right flange are leading. Didn't give it too much thought at the time because I figured it would be just like radial, only with longer spokes (the wheel was a front one). It looked the biz and it trued ok. I even ran it on a delivery bike one time in an "emergency" (bike + me + groceries about 225lbs I'd say) and it seemed to cope with no problem. One major advantage is that spoke length isn't really that important, as long as they're all the same length. However, I can't seem to find any evidence of people having done this before, might this be because it is a potentially dangerous pattern? Surely people must have thought of this before me but decided against it, why aren't people doing this?

 

[FluffyChicken]

Radial cannot rotate and so push the spokes into the tyre. (they are already at their shortest length)

Yours can and thinking in my head if you turn in one direction it'll loosen tension on ALL the spokes :s

But a picture would be cool

 

[PIGEON]

Hmm I don't think the hub can rotate in relation to the rim, the spokes on one flange could, if it weren't for the spokes on the other flange. They would need to stretch for the hub to rotate. It's a bit difficult to put into words but I hope you catch my drift.
I'll try to do a pic today, the wheel is behind a pile of junk right now

 

[FluffyChicken]

'Twist' should be the word, not 'Rotate' hence the turning force.

Just thinking in my head of course.

Think of rotating one side, see the spokes all shorten, add a twist (as they can now they are shorter and doing nothing). It may also cause the other side to unload, but doesn't need to as it can bend on the spokes.

To grip at the road in relation to the hub could cause the twisting/rotation force.

Someone on here will deal with this sort of stuff.

 

[dbmtb]

You're also putting a lot of opposing pressure on the central sleeve of the hub shell. Only ever saw one wheel built like this and the hub shell snapped due to the twisting forces.

 

[Easy_Rider]

Well you're certainly not the first to build a wheel that way.

Pic taken from another thread.

 

[pete_mcc]

Well you're certainly not the first to build a wheel that way.

All those wheels are radial, the op has a wheel with all leading on one side and all trailing on the other, a very different pattern and not one I'd be willing to try out....

 

[Easy_Rider]

Have a closer look, they looked radial at first to me but if you look at the far side its more obvious they definately look like there is one leading and one trailing. Especially looking at the lower half of the far wheel. Then again the closer wheel does look radial :?

 

[gump]

Its been done before and documented somewhere.
Could be called radial offset I think. Don't think much different to radial for all intents

 

[danson67]

Pigeon,

Three good reasons to use it:

1: As you say, almost any length spoke can be used.
2: Rarer than radial, twisted or crowsfoot patterns.
3: Looks really cool.

Two good reasons not to:

1: The torque exerted on the hubshell by the combined tension of the clockwise/anti-clockwise facing spokes will be huge. Normally this is balanced by the opposing spokes paired on a single flange.
Hubs are not designed to handle this force. If the hub centre failsin torsion, the wheel will instantly lose all tension in all the spokes and collapse.

2: Braking on the rim or disc will tighten the trailing spokes and loosen the leading spokes. This will causes the rim to move off centreline of the wheel towards the trailing spoke side. Brake rub, wobbly steering and possibly wheel collapse & physical injury :cry:

I built a wheel like this a few years ago, using a MAVIC 301 hub 32 hole.
This was on a road bike, it worked reasonably well and didn't fail, but still gave me a few frights before I decided to scrap it.

Don't use any spindly hubs or ones made from 2 flanges and a tube bonded together (TNT, Pace, Nuke Proof, Old Hope, Bullseye etc...).
Build it with huge fat stiff hub, as many spokes as possible, as close to tangential as possible.

IMHO it's just about OK if you use it in a straight line, on a front wheel with no brake.

It might be boring, but the tangentially spoked wheel has ruled the roost for over 100 years for good reason.

Take care out there