Bicycle Mechanics - Emergency wheelbuilding problem - leading spokes too short? Pic.

Hey all,

I just started lacing up a Miche 36h rear track hub (fixed/fixed, no dish) to a 36h Mavic Open Pro. Gene Spicer from Spicer Cycles and myself both independently calculated that the spokes should be 288mm long for 3x lacing (I used spocalc, he used shop software).

So I've been following Sheldon's guide, and installed all of the trailing spokes on each side without a hitch - when I was done, the hub was nicely centered in the wheel, and even the dish seemed right (yes, the spokes were still pretty loose - I still have about half of the threads showing). I could even hold the hub in my hand at this point and spin the wheel straight.

However - as soon as I tried to lace the first of the leading spokes, they don't seem to reach anywhere near where they should go! If I lace the spoke to cross three other (trailing) spokes on the same side of the flange, the leading spoke is short by a good 2 or 3cm. It's not b/c some of the nipples aren't seated in the rim all of the way.

It does seem as though it would fit in a 2x pattern, and that would be a disappointing mistake, b/c I want this to be 3x. But I don't think both of us made the same calculation error (I just checked again).

I've read and re-read the instructions a million times, and they make perfect sense to me - I just don't see why the hell this is happening.

Advice is very appreciated.

http://i35.tinypic.com/120jdck.jpg

In this next image you can see that it is crossing three spokes, as Retro Grouch suggested:
http://i34.tinypic.com/30stw0m.jpg

Are you sure that you're counting the crosses right? On a 3 cross wheel the forst cross is at the hub flange.

Note: I'm submitting this thread and then going to take / upload the pics. They should be up soon.

Hey all,

I just started lacing up a Miche 36h rear track hub (fixed/fixed, no dish) to a 36h Mavic Open Pro. Gene Spicer from Spicer Cycles and myself both independently calculated that the spokes should be 288mm long for 3x lacing (I used spocalc, he used shop software).

So I've been following Sheldon's guide, and installed all of the trailing spokes on each side without a hitch - when I was done, the hub was nicely centered in the wheel, and even the dish seemed right (yes, the spokes were still pretty loose - I still have about half of the threads showing). I could even hold the hub in my hand at this point and spin the wheel straight.

However - as soon as I tried to lace the first of the leading spokes, they don't seem to reach anywhere near where they should go! If I lace the spoke to cross three other (trailing) spokes on the same side of the flange, the leading spoke is short by a good 2 or 3cm.

It does seem as though it would fit in a 2x pattern, and that would be a disappointing mistake, b/c I want this to be 3x. But I don't think both of us made the same calculation error (I just checked again).

I've read and re-read the instructions a million times, and they make perfect sense to me - I just don't see why the hell this is happening.

Advice is very appreciated.


The only way I got close to useful wheels (My wheels are still works in progress) is I got a copy of Jobst Brandt's book, 'The Bicycle Wheel' and between it, Sheldon's Essay, and Wheelbuilding Videos on You Tube I was able to figure it out. I also started with a front wheel to work out the basics.

Thanks, but again I've read a few how-to's and I understand the concepts, I've just never heard of this happening. (Note that I did not ask 'How do I learn how to build a wheel' - this is a specific problem.) Also, as I mentioned, this is a fixed/fixed rear hub with symmetric dish on both sides (no dish), therefore is no more difficult than a front wheel.

Now that I've had a chance to see the photos, it looks to me like your spokes are too short. Your trailing spokes look too perpendicular to the hub for a 3 cross wheel. I'm thinking they should be leaving at more of a tandent.

How did you determine the ERD?

I hope you're wrong. If I was holding the wheel for those pics, I could twist the hub more counterclockwise to make the spokes cross at more of a tangent.

Looks to me like the already laced spokes are off. If you take the three spokes that you're crossing, there are three holes between the 1st and second, and two between the second and third.
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Scratch that. The lighting was playing tricks on my eyes.

Looks like the spokes are too short for a 3-cross.

Did both you and the LBS make independent measurements and calculations? Or just independent calculations off of the same set of measurements?

Loosen the spokes more and give the hub a big damn twist.

And since it's a Mavic rim, did you notice in the notes on Spocalc next to the Mavic rims that the program uses conventional ERD which is = to Mavic's NSD + 3mm. So I hope you didn't use Mavic's numbers

That's not right. Leading/trailing should be symmetrical, and they very obviously are not.

http://www.terminalvelocity.demon.co.uk/WheelBuild/4by2l.gif

svtmike: I'm not going to lie, the shop and myself both used the same set of measurements.

Bob: I did notice the notes in Spocalc next to the Mavic rims, however, I read many threads on the matter and not one person knew what that was about. Can you explain?

So yes, I ultimately did use Mavic's number. However, even if I calculate with the extra 3mm, I only get spokes that are 1.5mm longer, which rounded = 2mm. It doesn't look like that 2mm would give me extra length I need.

Or would it, since that 2mm would change the amount I could twist the hub, etc.?

Damnit.

svtmike: I'm not going to lie, the shop and myself both used the same set of measurements.

Bob: I did notice the notes in Spocalc next to the Mavic rims, however, I read many threads on the matter and not one person knew what that was about. Can you explain?

So yes, I ultimately did use Mavic's number. However, even if I calculate with the extra 3mm, I only get spokes that are 1.5mm longer, which rounded = 2mm. It doesn't look like that 2mm would give me extra length I need.

Or would it, since that 2mm would change the amount I could twist the hub, etc.?

Damnit.

I'm guessing here, but NippleSeatDiameter to me means the nipple/rim interface diameter measurement (the "bottom" of the head of the nipple). Unless I'm remembering wrong, ERD is measured to the "top" of the nipples. The assumed nipple head is 1.5mm in thickness.

I haven't done a wheel in ages, but...All the spokes are the same length, right? If so, the ones already laced should be the same distance from their spots on the rim as the one that is "too short" in the picture. I.e. if one is too short, all are too short - if you have the hub twisted the right amount and they are crossing in the appropriate pattern. No?

Yep, your spokes appear to be too short. The only thing I would suggest is to rethread each nipple only 1 turn and see if this gives you enough slack to twist the hub and get the cross spoke to reach. I kinda doubt it, but it's worth a try. Everything you've done so far looks right anyway.

Nope, you laced up the "leading" spokes first, not the "trailing" spokes. Sheldon calls them the ones on the inside of the hub-flange. I prefer to lace up all these heads-out spokes first because it's a lot easier to manipulate the heads-in leading spokes to do the crossing later. No messy bending and weaving needed.

Looks like spokes are too short as all the nipples on the laced-up spokes are fully seated. Try it again with 2x and I bet it'll be right on. Also helps to tighten each nipple only about 2-turns at first; just enough to hold, but will give you enough length to fully twist the hub. Makes it easier to get that 1st crossed spoke in.

Nope, you laced up the "leading" spokes first, not the "trailing" spokes. Sheldon calls them the ones on the inside of the hub-flange. I prefer to lace up all these heads-out spokes first because it's a lot easier to manipulate the heads-in leading spokes to do the crossing later. No messy bending and weaving needed.

You're a bit confused - those are in fact trailing spokes, not 'leading' spokes, as leading spokes face forward towards the direction of rotation (like my leading spoke that is too short).

However - you are right in saying that Sheldon generally laces the trailing spokes on the inside of the flange (opposite of my wheel), but this is a fixed-gear wheel, about which he says: "In the case of fixed-gear or coaster-brake wheels, it is better to lace the opposite way, because a derailed chain is more likely to get jammed by backpedaling in these cases."

He also says, "Note: This is not an important issue! There is a sizable minority of good wheelbuilders who prefer to go the other way around, and good wheels can be built either way." There is also this thread (http://www.bikeforums.net/showthread.php?t=397738) on BF with various opinions regarding this issue.

The more I look at it the more it looks like a 3X/2X mix-up. Try moving the heads-out spoke in the pic to the next vacant hole clockwise and see how it fits.

I might be able to make 2x work, but I recalculated the spoke lengths (3 cross) using an ERD of 605 (instead of 602) and a flange diameter of 59mm (instead of 60mm) and I end up with spokes that are 2 or 3mm longer than what I bought.


Do you think 2 or 3mm longer spokes would be enough to make these spokes reach?

.. I recalculated the spoke lengths ..and I end up with spokes that are 2 or 3mm longer than what I bought.

Do you think 2 or 3mm longer spokes would be enough to make these spokes reach?

Offhand, no. But it's a tough call to make based on your pic. If you look at your lower pic you can see how much you'd need to rotate the hub clockwise before the heads-out spoke head will be aligned with its corresponding heads-in spoke that's already in place.

I might be able to make 2x work, but I recalculated the spoke lengths (3 cross) using an ERD of 605 (instead of 602) and a flange diameter of 59mm (instead of 60mm) and I end up with spokes that are 2 or 3mm longer than what I bought.


Do you think 2 or 3mm longer spokes would be enough to make these spokes reach?

I coubt it. It looks like you have already twisted the hub enough to almost seat the nipples and you have about 10 or 15 mm left (guessing). If I were you I would try a 2 cross pattern and see what happens. It is only a front wheel, after all.

dabac, thanks for the reply. Which spoke is the corresponding heads-in spoke, the one 180 degrees away on the same flange?

LarDasse - it's a rear wheel, on a fixed/fixed hub.

Which spoke is the corresponding heads-in spoke,

If you look at a cross-laced wheel you'll notice that (on each side) you'll have pairs of spokes that run almost parallell to each other. For a 3X there should be 6 holes at the hub between these paired parallell spokes, so simply count off 6 holes counter-clockwise to see which heads-in spoke your heads-out spoke in the pic should run "parallell" to.

For 2X you should have 4 empty holes between the spokes in the "parallell" pair.

You're a bit confused - those are in fact trailing spokes, not 'leading' spokes, as leading spokes face forward towards the direction of rotation (like my leading spoke that is too short).I don't like using the term 'leading' or 'trailing" just because of this confusion. The real issue here is one of heads-in versus heads-out on the spokes. When you install the heads-in spoke first, it gets really difficult later when you install the heads-out spokes. You end up having to thread the spoke through already-crossed spokes on the opposite side and have to bend the spokes severely in order to thread them through the opposite site. It's better to install the heads-out spokes first, then do the heads-in ones later.

+1

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

That would be a 2-cross. He's trying to do a 3-cross.

Sorry. I thought he was going for the 3X on the finished wheel.

Alright.

I've checked everything, and the spokes are definitely too short for 3x lacing.

So here's the rub:

Mavic gives an ERD of 602mm for this rim. Spocalc and others (i.e. Bob Barker earlier) say to use 605mm for the Open pro.

However, I've also recalculated the lengths, and had even another person do it, and the difference between 605 and 602 is, at the most, 2mm.

I'm not sure 2mm longer spokes would be enough to get the spoke all the way to the nipple.

But am I right in thinking that 2mm longer spokes will actually get the spoke ~3/4mm closer to the nipple? Reasoning: if the trailing spokes are 2mm longer, I can rotate the hub further counterclockwise, bringing the spoke a few mm closer. Then my 'short' leading spoke will also have 2mm more length itself, for a total of 3/4mm. Make sense?

So how will I determine how much more length I need? I guess my first step would be to measure the ERD myself, and the hub, as per Damon Rinard's instructions (http://www.sheldonbrown.com/rinard/spocalc.htm#MeasureHubAndRim) on Sheldon's site.

Here's what you do. Get 4 spokes of the longer length. Lace in 3 trailing spokes on one side equally spaced (since there are 18 holes per side, put in a spoke every 6 holes. Twist the hub. Put in your leading spoke and see if it is long enough. You'll probably want to use the picture you took previously for reference so you can locate an appropriate rim hole for the leading spoke. I know that this doesn't take dish into account, but that is a very minor factor and can be ignored.

If it fits, take out the leading spoke, buy the rest of the spokes and finish building the wheel as you normally would. I would also consider having your leading spokes head-in as that will be much easier to build. Thinking about it, I think if you want to have the leading spokes head-out, you need to build the wheel "backwards," e.g. leading spokes first, trailing spokes second.

Good idea - will do.

Regardless, it still doesn't make any/much damn sense that these #&*@%*! spokes are too short. The calculations can't be that wrong.

Good idea - will do.

Regardless, it still doesn't make any/much damn sense that these #&*@%*! spokes are too short. The calculations can't be that wrong.Post the caculator you used and the measurements you entered into it. I've found that online forms can have cache issues where they store previous entries while showing something different on the screen.

Thanks, but again I've read a few how-to's and I understand the concepts, I've just never heard of this happening. (Note that I did not ask 'How do I learn how to build a wheel' - this is a specific problem.) Also, as I mentioned, this is a fixed/fixed rear hub with symmetric dish on both sides (no dish), therefore is no more difficult than a front wheel.

Uh.. You can put your faith in Sheldon's article; but a picture is a worth a thousand words. His illustrations are just not clear enough without supplementary material.:rolleyes:

Could it be possible that the database measurements for your hub are wrong? Measure up the hub and make sure you are ballpark. I would disassemble and pull all the measurements myself. But that's just me. If it turns out your spokes are too short sell them on eBay.

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

+1

I know you did not "ask 'How do I learn how to build a wheel'" but peep this a sec: http://sheldonbrown.com/wheelbuild.html#leading

Do yourself a favor and buy the best darn wheelbuiling book out there by Roger Musson: http://www.wheelpro.co.uk/wheelbuilding/book.php. It covers every topic and his lacing instructions are SIMPLE and EFFECTIVE.

Good luck!

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

Actually, that's not correct. What has happened is that he has laced the trailing spokes on the opposite (left) side of the hub behind (ccw) the trailing spokes on the near side. This is opposite from Sheldon's diagram. As has been pointed out before, the trailing spokes are also laced head-out instead of head-in.

OP, when you get your longer spokes, don't be fancy, follow Sheldon's directions exactly so that you can easily reference his diagrams. Head-in, head-out, the only difference you'll ever notice is that one way is a lot easier to build than the other.

You're trying to connect to the wrong spoke hole. In the upper picture, rotate the short spoke either 4 or 5 holes counterclockwise. (I think 5, but hard to see from the pic)

Correct. What the OP actually has, in the second picture, is a *5*-cross. You count all the spokes that are crossed, when all the spokes are in. You don't have all the spokes in yet, so you're currently only crossing three with that spoke which you think is too short. If all spokes were shown in that photo, that spoke would be crossing 5.

The lacing mistake could explain the whole problem here.

[Edit: I think I'm wrong...]

Actually, that's not correct. What has happened is that he has laced the trailing spokes on the opposite (left) side of the hub behind (ccw) the trailing spokes on the near side. This is opposite from Sheldon's diagram. As has been pointed out before, the trailing spokes are also laced head-out instead of head-in.


Sorry, nope. Whether the "trailing" spokes are head-in or head-out, makes no difference at all in spoke length (there are other reasons for choosing one over the other, and much disagreement about what is best--but none of those reasons relates to spoke length). The spokes in the pictured wheel so far are fine, except for the first crossing spoke. The OP is simply trying to put the first crossed spoke into the wrong hole, as I-bRAD said.

Sorry, nope. Whether the "trailing" spokes are head-in or head-out, makes no difference at all in spoke length (there are other reasons for choosing one over the other, and much disagreement about what is best--but none of those reasons relates to spoke length). The spokes in the pictured wheel so far are fine, except for the first crossing spoke. The OP is simply trying to put the first crossed spoke into the wrong hole, as I-bRAD said.

Sorry, nope. My point was that the OP did not lace his wheel consistent with Sheldon's diagram. In fact, the nipple in his picture is in the correct position for a 3x wheel according to his lacing pattern, and is in a position that alternates with the spokes on the other side of the hub. Take a look. The difference is that his trailing spoke positions on the left vs. right side of the hub are swapped vs. Sheldon. In addition, he has also chosen a different head-in/head-out order which does NOT affect spoke length (I didn't say it did), but which is ALSO different from Sheldon's diagram, and which WILL make it more difficult to lace the wheel.

He needs to start over, and most likely use longer spokes. But in any case, it is a good idea to follow directions exactly. Once he has built up a successful wheel (or two or more), then he can get fancy and build them trailing head out, etc. if it makes him happy. Right now, he's just frustrating himself and confusing the rest of us.

Correct. What the OP actually has, in the second picture, is a *5*-cross. You count all the spokes that are crossed, when all the spokes are in. You don't have all the spokes in yet, so you're currently only crossing three with that spoke which you think is too short. If all spokes were shown in that photo, that spoke would be crossing 5.

The lacing mistake could explain the whole problem here.

Not correct - you only count the spokes crossed on the same side of the hub. He is only crossing 3 on the same side in his picture.

Not correct - you only count the spokes crossed on the same side of the hub. He is only crossing 3 on the same side in his picture.

No, that's not true. You count the crosses of all spokes on the same *flange* of the hub, not on the same *side* of the flange (if that's what you meant). Count all the spokes crossed on the same flange of the hub. The very first cross will be the spoke which comes out of the very next hole on that same flange of the hub (regardless of head-in or head-out orientation).

EDIT--please disgregard this comment. I misunderstood...

Sorry, nope. My point was that the OP did not lace his wheel consistent with Sheldon's diagram. In fact, the nipple in his picture is in the correct position for a 3x wheel according to his lacing pattern, and is in a position that alternates with the spokes on the other side of the hub. Take a look. The difference is that his trailing spoke positions on the left vs. right side of the hub are swapped vs. Sheldon. In addition, he has also chosen a different head-in/head-out order which does NOT affect spoke length (I didn't say it did), but which is ALSO different from Sheldon's diagram, and which WILL make it more difficult to lace the wheel.

He needs to start over, and most likely use longer spokes. But in any case, it is a good idea to follow directions exactly. Once he has built up a successful wheel (or two or more), then he can get fancy and build them trailing head out, etc. if it makes him happy. Right now, he's just frustrating himself and confusing the rest of us.

Doug, I see what you're saying, but there is a lot to be gained by understanding the basic principles of wheelbuilding, and that's what I'm getting at. How to count the crosses is very basic, and extremely important. Understanding what does and doesn't cause problems of spoke length, that's also important knowledge. It's a very useful exercise to puzzle this out and try things. There is a time to bail, and this is not it. There are very fundamental errors being made here.

[Edit--including errors being made by ME. :o]

As for orientation of the "trailing" spoke heads, not all experts agree on that.

You are missing my point. I don't have an opinion on which spoke head orientation is better, I'm just pointing out that it is easier to lace the cross spokes when they are threaded from inside to outside (e.g. head-in), because then your first two crosses are outside, you only have to bend the spoke for the third lace, and you don't have to mess with the spokes on the other side of the hub. If you've ever had to replace a broken "head-out" spoke, you'll know what I mean. If you want to reverse the head orentation, that's fine, but then you'll want to build the wheel in a different order (leading spokes first). It's all about ease of building.

As to "How to build a 3X wheel," I can think of at least 4 different approaches and it doesn't really matter (to me, anyway) which one is used. Since we BFers are using Sheldon's build as our reference, I'm just pointing out that the OP did NOT build his wheel consistent with Sheldon's directions (not that he was following them at the time). Because of this, we can't make direct comparisons to Sheldon's diagrams. Specifically, the nipple location APPEARS to be offset by one hole from Sheldon's diagram. However, if you delete all of the trailing spokes on the opposite side of the hub and just look at the spokes on the near side, you will see that the OP has chosen the correct hole in the rim. It is the spokes on the opposite side of his wheel that are located differently from Sheldon's diagram (OP's are offset CCW by 1 hub hole and/or 2 rim holes from Sheldon)

Bottom line, I'd suggest that the OP start over following Sheldon's directions exactly and see what happens. (I still think he needs longer spokes). Once he has successfully laced his first wheel, he can try doing variations, but it would be a good idea to get the first one out of the way using a clear and proven set of directions.

You are missing my point. I don't have an opinion on which spoke head orientation is better, I'm just pointing out that it is easier to lace the cross spokes when they are threaded from inside to outside (e.g. head-in) ...It's all about ease of building.


We have to agree to disagree on this. This has nothing whatsoever to do with the issues that the OP is having. It may be comforting for some people to build only a certain way, but it has nothing at all to do with the issue at hand.



... if you delete all of the trailing spokes on the opposite side of the hub and just look at the spokes on the near side, you will see that the OP has chosen the correct hole in the rim.


No, this is not correct. I'm sorry, but NO, it's not correct. I am looking at just the near side. If you still think that his crossing spoke is only crossing three, you are being confused by the fact that some of the spokes on the near flange have not been placed in their holes yet. Try to imagine them there.

[EDIT--I'm wrong, my mistake--those missing spokes would all be going the same direction as the crossing spoke, so they wouldn't be crossed by it.]

As for saying that BF'ers use Sheldon's method exclusively, I don't think that's true--at least it wasn't when I posted regularly a couple years ago. We used to discuss all the methods, and learned a LOT that way. Sheldon was a great great man, and I have nothing but admiration and respect for all that he gave us in his lifetime. But his spoking method is so exhaustively detailed, that it can displace the mechanic's responsibility to think about and understand what he or she is doing. It's fine for someone wanting to just build a wheel once or twice for the experience, without having to learn much about the principles involved. But I digress.

How many bf members does it take to lace a wheel?

Please provide your ERD and hub specs..

Oh *****. Am I right? Wait, maybe not! I'm wrong. Looking at the blowup provided by urban_assault, suddenly I think I'm going to be apologizing. Those missing spokes are all going to be going the same direction as the crossing spoke, therefore the crossing spoke would not cross them. It should indeed only cross the ones that are already in on this flange. I was wrong. Sorry Doug, sorry everyone. sorry sorry sorry.

The angles are too steep on the spokes that are in (as someone pointed out on the first page), and maybe that *is* because the spokes are too short. I am hereby disqualifying myself from any further discussion. Did I mention that I'm sorry? :(

lawkd is right. Count the spoke holes on the flange. The OP is crossing 5 spokes.

Pretty obviousPretty obvious also that spokes 2 & 4 are going in the same direction as that 1st crossed spoke and will NEVER cross that spoke. The picture shows correct orientation for 3x, the spokes are too short.

If the OP would just give us the numbers he used, we can figure out what went wrong and where:

hub-flange = 38-42mm?
flange-width = 50-65mm?
ERD = ???
cross = ?

Most of the time when I'm off by this large of an amount, it's because I had the wrong cross# in the calculator, usually off by about 10-15mm. ERD variations are typically less than 5mm.