Inside or Outside the Flange

[Diesel6]

I have built a few of my own wheels according to Lennard Zinn's instructions. He says the trailing spokes should run outside the flange.

I've recently read some web instructions of Sheldon Browns. He says the trailing spokes should run inside the flange.

Both are pretty well respected mechanics. Any thoughts on who is more correct (i.e. whether inside or outside the flange is more correct). I am talking mainly about the drive side on the rear wheel.

 

[bobbyOCR]

Outside the flange will create a stiffer wheel due to a greater bracing angle. That 1mm makes a big difference when it comes to stiffness.

 

[Retro Grouch]

Outside the flange will create a stiffer wheel due to a greater bracing angle. That 1mm makes a big difference when it comes to stiffness.

Of course, that means that the leading spokes will be inside the flange and have a lesser bracing angle. On average, the spoke bracing angle going to be equal whichever way you lace them.

 

[Diesel6]

Thanks guys for your input. The more I've read the more I'm convinced the leading spokes need to go outside the flange. The only reason they would run inside would be if you need the clearance I imagine.

Anyway, I think I'll continue to build with them running on the outside.

Thanks.

 

[Retro Grouch]

Thanks guys for your input. The more I've read the more I'm convinced the leading spokes need to go outside the flange.

I've always built mine with the pulling spokes inside the hub flange. Originally my reasoning was because that's the most direct route from the hub to the rim. Today, after reading enough conflicting engineering theories to make me dizzy, I still build them that way but I don't have a strong opinion that either way is superior to the other. The truth, as you have already noted, is that some pretty smart people do it each way.

 

[Phill P]

The "pulling spokes" going anti clockwise should be on the outside. This decreases the static tension required in those spokes to counter the non drive side spokes. Additionally the clockwise spokes need higher tension static tension to do the same job. Both of those factors are important.

When you stomp on the pedals, the "pulling" spokes will gain a little tension, the "pusher" will loose a little.

Wheels will fail in two ways, fatigue of a spoke, or tension loss in a spoke.

The lower average tension in the pulling spokes means it is less likely to fatigue with the fluctuating driving loads. Additionally the higher average tension in the "pushing spoke" means it is less likely to go completely slack if it loosens over time.

Hub shells of Al are fairly flexable, so non driveside spokes do very little to rotate the rim compared to 3x drive side spokes. Hence so many high end wheels use radial non drive side. I don't know how Shimano and Mavic get away with radial drive side and crossed non drive to transmit torque.

 

[Diesel6]

While I'm at it, I have another couple of questions...

Is there a general rule with crossing spokes such as - the spoke goes over the top of the first spokes (1 in the case of 2X and 2 in the case of 3X) and then always under the last cross? Is there ever a case where the spoke goes under a crossing spoke prior to the last one it crosses?

And..

I'm really keen to build a 36 spoke crows foot. The spoke length for the radials is straight forward obviously, but are the crossing spokes calculated with the normal 3X formula?

 

[Retro Grouch]

The "pulling spokes" going anti clockwise should be on the outside. This decreases the static tension required in those spokes to counter the non drive side spokes. Additionally the clockwise spokes need higher tension static tension to do the same job. Both of those factors are important.

That sounds goofy to me. The beauty of a tension wheel is opposing pairs of spokes pulling against each other. Every spoke affects the tension of every other spoke. So how can you have all of the clockwise spokes tensioned more than all of the counter-clockwise spokes? Wouldn't it just pull the hub around until the tensions were equal?

 

[jmocallaghan]

Trailing = outside. The spokes are going to stretch and tension placed on them in a pulling fashion will result in compensating for that stretch via winding up. This gets to be important if you're using a thick guage spoke (14 or so) with a 10 speed drive chain because of the clearace from the cassette.

Pushing = outside. Tension is more static on a pushing spoke. Your tension between pulling and pushing should be w/in 5lbs of each other.

 

[Phill P]

That sounds goofy to me. The beauty of a tension wheel is opposing pairs of spokes pulling against each other. Every spoke affects the tension of every other spoke. So how can you have all of the clockwise spokes tensioned more than all of the counter-clockwise spokes? Wouldn't it just pull the hub around until the tensions were equal?

Thats a very good point, perhapes there is a bracing effect from the other side of the hub.