Myosmith

I noticed something I think is odd about a set of wheels I acquired. On all of the other wheelsets I have, the spokes from one side to the other are mirror images, ie the pulling spokes come from the inside of the flanges and the trailing spokes from the outside. On this particular set, the pulling spokes are on the outside of one flange and the inside of the other. Is there a reason to spoke a wheel this way? Advantage/disadvantage?

Retro Grouch 

Faster for machines to lace them.

Myosmith

These were hand built and all of the machine built ones I own have the spokes in the mirror image pattern. Since these were hand built and vary from the machine built ones, I was wondering if there was a benefit to lacing them this way.

FBinNY 

It's not so much a machine vs hand building issue, since all "machine built" wheels are still laced by hand.

It's a question of builder (lacer) training and habit. Most production builders (humans) develop a preference for lacing in one direction, and are much faster if they can do both flanges the same way. The fastest way is to (with the wheel horizontal) lace the lower flange first, then the upper. If doing it all the same way, you end up with a wheel like yours.

OTOH, you can lace the upper flange first, Then flip the wheel and do the other flange. The work is identical, so the only added step is flipping the wheel. In larger companies the lacers are paid on piecework (some make good money this way) so they don't like to lose the 5 seconds or so that flipping the wheel involves.

This is why OEM wheels tend to be like yours, and better wheels are mirrored --- 5 seconds/wheel x 100,000 wheels.

noglider 

I don't think there are any advantages or disadvantages to the different approaches, except that some find one approach or another easier to lace. I do them in mirror image.

fietsbob

Dis advantage of Inside* head in spoke radiating CCW comes when you over shift the chain
and the spoke pattern firmly pulls the chain hard into it .
Almost guaranteeing a tight jam behind the low gear cog.
and Immediately cutting through a few spokes to failure. as chain is pulled in tightly..

it's then 'Dork Discs' dont seem so Un Welcome..

* fixed my dyslexic fingers typing the wrong in/out .. hands went into error mode..

FBinNY 

The disadvantage of non-mirrored comes into play with stronger riders. When the wheel is torqued, the spokes from either flange both transfer tension from pulling to non-pulling in such a way as to deflect the rim in the same direction. With mirrored lacing, the spokes cancel each other out.

While the total change isn't big either way, and won't noticeably affect function, it does mean increased total deflection with each torque cycle, and would tend to shorten fatigue life. This among many subtle factors is why OEM wheels usually have shorter service lives than hand built wheels.

I agree, except that Fietsbob has it exactly backwards. With outside spokes (elbow out, head in) radiating counter-clockwise, namely "pulling" spokes, the spinning wheel would have the spokes act as ramps lifting the chain away form the hub. If these spokes radiate froward, the wheels motion would have them slip over the chain and wedge it lower jamming it tightly between the cassette and flange.

I might add that this is one of a number of fine points where I disagree with J. Brandt whose book The Bicycle Wheel is considered the bible by many wheelbuilders. JB recommends building wheels with pulling spokes elbow in, so they cross outside the non pulling spokes. His rational is that under load, such as climbing in low gear, the stress would deflect the point of cross inward, away from the chain and derailleur, and lessen the chance of snagging the RD cage.

OTOH, I (and most European builders) build pulling spokes elbows out, to avoid jamming an overshifted chain. IMO, there's enough clearance between the RD and spokes so the deflection factor can be discounted, but simple overshifting is more common.

This is a very niggling point, and you can agonize over it, or toss a coin. I just offer it so if you hear a strong advocate of one way or the other, you'll know both sides of the issue.

davidad

Call them spoke protectors. That's what they are and they do a great job for the few times that a chain dump happens. Don't ask me how I know that.

davidad

Years ago Mavic built wheels with the different lacing patterns and determined that the most reliable were the ones with the "pulling" spokes laced with the heads inside the flanges. I use Schraner's method of spoking a wheel and that is how they come out.

tomacropod

Building a wheel symmetrically also aids in gaining even spoke tension during hand building. Because the "heads in" spokes cross to the outside of the flange, they actually travel further from the rim than the "heads out" spokes. If both sides of the wheel are laced this way, you can simply count turns (or use a velocity/problem solvers nipple driver) and gain even tension rather than alternating tension, with the rim being very marginally forward or backward from the midpoint between the spoke holes in the hub. This speeds up hand building.

- Joel

Kimmo

Hah, I knew it wasn't just aesthetic, but all I've had until now on this score was my intuition.

Still, I guess it only applies to rear and hub-braked wheels, since it's based on torsion.

noglider 

FB, would you please stop being so reasonable?

FBinNY 

Yes, it only makes a difference with hub torque.

cyccommute 

Not all of them. This video shows a machine lacing


And I've seen others. Oddly enough, this is a symmetrical wheel lacing (mirror image).

FBinNY 

Yes, times change. I haven't been to a factory in a few years, and missed a number of overseas trade shows.

But as you point out, mirror or non-mirror lacing aren't an indicator of whether a wheel was laced by hand or not.

Another example of why we should never say never again.

cycle_maven

Having overshifted on wheels built both ways, the fact is that the act of overshifting into the spokes isn't what damages the wheel worst. With the head-in spokes radiating clockwise, you overshift, but then you coast when you realize something is wrong. This immediately sucks the chain right down between the cassette and spokes, destroying the wheel, derailleur and hanger. The other way, you have a chance to stop with just a few dinged spokes unless you continue to grind away. I only have personal experience of two, so YMMV. Clockwise- dead bike. Counter-clockwise- a few dinged spokes.

Kimmo

Wow, imagine designing and building that puppy.