Bicycle Mechanics - Wheel Building Question...rear pulling spoke orientation...

As follow up to my recent post regarding titled "Wheel Building Mistake", I now have a question regarding spoke orientation. In the previous thread, I learned that 1) orientation of the spoke pattern to maximize the space surrounding the valve hold is a cosmetic and convenience matter rather than a structural issue and 2) the "countersinks" of a Campagnolo C-Record hub are not meant to serve as a "pocket" for the spoke head (although a mechanic at a local shop who was building bikes in the 1980s disagrees).

Again, my initial questions and my follow-up question relate to a standard Campagnolo C-Record 32-spoke aluminum hub, aluminum rim and steel spoke set-up (no fancy carbon fiber or modern spoke technology).

My follow-up question is:

In a rear wheel, does it matter what direction the rear drive side "pulling spoke" enters/exits the hub flange. In other words, is it okay for a rear drive side "pulling spoke" to enter from the outside of the hub, travel through the flange, exit the flange on the inside of the hub and then proceed to the rim? This would leave the head of the rear drive side "pulling spoke" facing outwards, towards the freewheel. Consequently, all the rear drive side "pushing spokes" then enter the flange from the inside of the hub, travel through the hub, exit the flange hold on the outside of the hub and then travel to the rim.

IIRC from Sheldon, the main advantage of lacing the leading/trailing spokes in the preferred orientation is that it eases the removal of a chain dropped between the first cog and the hub flange.

There's no right or wrong regarding whether the driving spokes should come from the inside or outside of the flange. There are benefits and drawbacks to either way. Here are some of the considerations.

1- Assuming the spokes are interlaced outer under inner at the last cross, the point of the cross will be pulled either inwards or outwards as the hub is torqued. With driving spokes off the inside, they'll be at the outside at the cross and the point of cross will be inwards, increasing chain and derailleur clearance, and lowering side loads at the rim.

2- With the the pulling spokes off the outside, the turbine will be such that if a chain were to overshift beyond the cassette, the spokes will act as ramps trying to lift it out. If the outer spokes point forward (clockwise) they'll act as ramps driving the chain down towards the hub, making a minor problem worse.

3- I also feel that the outer spokes are better stabilized by the flange and therefore less prone to fatigue. In my experience it seems that inner spokes tend to break more often. But it's still only my opinion, based on my experience.

Therefore, for reasons flange support, and not trapping overshifted chains, I feel that pulling with the outer spokes makes more sense. But that doesn't make the other wrong. Other builders might be more concerned with deflection at the cross, especially with very close clearance between the RD and spokes and conclude that this trumps my considerations. The differences are minor and you can decide which way for yourself.

I follow Sheldon's advice, and lace pull spokes heads out. I just started reading Roger Musson's book and he prefers it the other way. Eventually it comes down to your own preference. There is no right or wrong.

2) the "countersinks" of a Campagnolo C-Record hub are not meant to serve as a "pocket" for the spoke head (although a mechanic at a local shop who was building bikes in the 1980s disagrees).
He's wrong. I've been building Campagnolo hubbed wheels (that had the countersink on one side only) since the early '60s and it was always well known that the countersink was for the spoke bend, not the head.

As for your spoke orientation question - the answer is that it doesn't matter. There are two major hub players (Shimano and Chris King I think) that have opposing views. Many of us have proved that it makes no difference; it's just personal preference based on whatever theory makes most sense to us. Me - I like the final cross of the rear drive side to have the puller on the outside (which makes it a head-out spoke) so that low gear pedaling torque pulls that cross away from the derailer cage. Other than that I don't care.

All pulling in...or all pulling out. Pick one...each has a benefit...but either way...your wheel will be just fine.

And just for your information...the mechanic you mentioned in regards to the Campy counter-sunk hole issue...obviously did not pay attention to EXPLICIT documentation from Campagnolo on the issue. On the few occasions where I built C-Record hubs - paperwork indicating the spoke orientation for countersunk holes was IN THE BOX.

=8-)

Hey...I just noticed I've become a Senior Member. I wonder if that's because I've posted a certain number of times, or because I've now learned the finer points of building wheels using C-Record hubs.

BTW, my near-final conclusion on the subject is that the spoke elbow rests against the C-Record countersink (at this point, too many of you have vehemently posted in favor of this view and virtually nobody has defended the mechanic). Today, during lunch, I'll be traveling the distance to a shop way on the other side of town that's likely more familar with old C-Record hubs. I'm sensing he'll side with you guys...in which case I'll be buying all new spokes and redoing the wheels one last time, regardless of any additional stress that might impart on my precious NOS Campagnolo hubs and rims.

With respect to valve hole positioning, I've put these wheels together enough times now that it's unlikely I'll ever get so disoriented that the valve hole won't be properly positioned in the widest gap in the spoke pattern...although it's good to know that, if it ever happens, it's not a structural concern. Regarding whether drive side pulling spokes get inserted towards the inside or outside of the hub...well, seems like that's a toss-up...so I might try both ways since I'm working on two bikes at the moment.

Looking back, it's amazing that these points are so developed in my mind, as only days ago I had never built a wheel and wouldn't have been able to appreciate any of this discussion. So, it seems I've learned a lot about wheel building...it's unfortunate, however, that a NOS C-Record rear hub and one in very, very good used condition may have been sacrificed in the process.

Thanks again.

Hey...I just noticed I've become a Senior Member. I wonder if that's because I've posted a certain number of times, or because I've now learned the finer points of building wheels using C-Record hubs.

BTW, my near-final conclusion on the subject is that the spoke elbow rests against the C-Record countersink (at this point, too many of you have vehemently posted in favor of this view and virtually nobody has defended the mechanic). Today, during lunch, I'll be traveling the distance to a shop way on the other side of town that's likely more familar with old C-Record hubs. I'm sensing he'll side with you guys...in which case I'll be buying all new spokes and redoing the wheels one last time, regardless of any additional stress that might impart on my precious NOS Campagnolo hubs and rims.

Looking back, it's amazing that these points are so developed in my mind, as only days ago I had never built a wheel and wouldn't have been able to appreciate any of this discussion. So, it seems I've learned a lot about wheel building...it's unfortunate, however, that a NOS C-Record rear hub and one in very, very good used condition may have been sacrificed in the process.

Thanks again.

Why would you rebuile replacing the spokes yet again. Even if you did a poor job the wheel will have some degree of usable life, (until you find a deep enough pothole) so having spent the dough, and put in the effort it would be a wasteful sin to simply trash it. Ride your wheel until it needs a rebuild, following the old adage "if it ain't broken, don't fix it"

If you want more practice, find some friends with dead wheels and rebuild those instead.

BTW- I strongly doubt the hubs are "sacrificed" in any way, and even if the flanges are weakened, they aren't cracked until they crack, which might very well not happen in this century.

Object lessons are fine, but if you can afford to throw dough around needlessly, send some my way.

Mavic built a number of wheels using the various spoking patterns for the rear wheel The ones with the pulling spokes heads inside the hub in a mirror image had the fewest problems with broken spokes.

And don't forget to position the hub so that you can read the logo through the valve hole on the rim!

<Minor thread hijack> Replacing a hub.. can I use the same spokes assuming they are the right length?

<Minor thread hijack> Replacing a hub.. can I use the same spokes assuming they are the right length?

some will say no, some will say yes. It is a largly debated issue. I say sure wont hurt anything.

I don't believe in re-using spokes because they are the stressed parts and usually the first to go short of a crash. Why put the time and effort into building a wheel if what is already the weakest link is pre-weakened some more.

That said, if you do re-use spokes, keep those with heads inside the flange separate form those with the heads outside. Re-use them in the same positions. My reasoning is that the elbows are already set to a slightly different angle, so you don't want to change that.

If you know the history of the previous wheel - i.e., spokes were fine and did not show a recent history of fatique such as periodic broken spokes - and the spokes are DT, Wheelsmith, Union, Alpina, Echelon or of decent quality...it is worthwhile reusing them if you are on a budget.

I reuse DT frequently. Has never been an issue for me. Nor will I toss DT spokes...unless I know they have shown signs of fatique or show obvious damage such as that which occurs with a dropped chain.

=8-)

If you know the history of the previous wheel - i.e., spokes were fine and did not show a recent history of fatique such as periodic broken spokes - and the spokes are DT, Wheelsmith, Union, Alpina, Echelon or of decent quality...it is worthwhile reusing them if you are on a budget.

I reuse DT frequently. Has never been an issue for me. Nor will I toss DT spokes...unless I know they have shown signs of fatique or show obvious damage such as that which occurs with a dropped chain.

=8-)

You can't see fatigue, nor measure spokes for how much of their life expectancy is used up, the way you can measure a chain for stretch.

The fact is that spokes do have a finite life expectancy, which varies with the quality of the original build, and the conditions of use; heavy rider, lots of hard hill climbing, bar roads, etc.

It boils down to the value you assign to your time. You know how much replacing the spokes will cost, and if building for yourself can decide if it's worth your time to save the dough. It also depends on what you're expecting from the new wheel. For instance if you were building a wheel for a planned cross country tour vs. a training wheel for off season use.

When building for your own use, re-using spokes is a personal decision, but I consider re-using spokes when building for sale to be the epitome of unprofessionalism, and if a client asked me to reuse his spokes, I'd decline the work. Re-using hubs is fine and makes sense, since a decent hub is valuable and will easily survive many builds unaffected. But for me, spokes and rims are strictly use once, throw away* items.

*recycle SS spokes and aluminum rims after punching the eyelets out.

Jobst Brandt, author of The Bicycle Wheel, says he reuses spokes repeatedly. That's enough for me. Maintaining adequate tension reduces stress on spokes. I believe -- and I could be wrong -- that spokes are either fatigued or they are not. In other words, they don't gradually lose strength. So if you have reason to believe they are not weakened, then they are as strong as when they were new.

Jobst Brandt, author of The Bicycle Wheel, says he reuses spokes repeatedly. That's enough for me. Maintaining adequate tension reduces stress on spokes. I believe -- and I could be wrong -- that spokes are either fatigued or they are not. In other words, they don't gradually lose strength. So if you have reason to believe they are not weakened, then they are as strong as when they were new.

Fatigue isn't digital, or absolute like being pregnant or not. It's a matter of degree and progresses based on the number and severity of stress/relax cycles. A used spoke is per se more worn than a new spoke, though how far along, and how material it is is variable and unmeasurable.

Jobst Brandt is free to reuse spokes, as is anyone else, making their own calculated cost/benefit decision, but that will never mean that used spokes are in fact as good as new.

I take your word for it that fatigue isn't boolean. Still, most of the time, most used spokes are good enough. If, however, you have ever broken a spoke, I would not reuse any spokes from that wheel to make a new wheel.

All spokes will fail (from fatigue) eventually. It's the speed at which the fatigue happens that matters. A good build prolongues the inevitable. I'll reuse spokes for a rim replacement, but I'd take a closer look if it were a new hub (lot's of angles change and there's no guarantee they will be oriented exactly the same way as before). Brandt's point is you should be able to go through several rims before the original set of spokes go bad.

I take your word for it that fatigue isn't boolean. Still, most of the time, most used spokes are good enough. If, however, you have ever broken a spoke, I would not reuse any spokes from that wheel to make a new wheel.

As I said, it's a personal decision. For some of us, "good enough" just isn't good enough, and for others it is.

I reiterate, there's a critical difference in what one does for personal consumption vs. what is acceptable from a professional.

The problem with reused spokes isn't that they're so much more prone to failure, but that there's no way to know for sure. That uncertainty, means I can't stand behind my work to the same extent I normally would. The first step in any serious quality control program is certifying the quality of the raw material. Starting out with spokes whose provenance is unknown nullifies everything that comes later. GIGO.

Well put, FBinNY, and I agree with that. I have different standards when I'm taking people's money to work on their bikes than I do when working on my own.

I take your word for it that fatigue isn't boolean. Still, most of the time, most used spokes are good enough. If, however, you have ever broken a spoke, I would not reuse any spokes from that wheel to make a new wheel.


Which was my point exactly.

Thank you Choir!

:D