wheelbuilding with arup

The 3–cross pre–cross method

This page will take you through the pre-cross method. Please see the disclaimer on the right.

Disclaimer:
I cannot be held responsible for wheels that you build using this method. If you are new to building wheels, then please have your finished wheel checked by someone who is experienced e.g. at your local bike shop.

This is quite a long page, so here is a list of contents:

As I mentioned on the home page, experienced wheel builders may have tried this method already and have another name for it. I must say I haven't come across it before, but I'm not involved in the bike mechanics world.

The easiest place to start for a beginner I think is with a finished wheel and work backwards. If you have a spare wheel knocking about in your shed then great, or you may find one dumped in a skip. You can also use the ones from your bike, but only for the first few stages.

Remove the tyre, tube and rim tape. Then just inspect. How many spokes are there? Are the spokes all in the centre of the rim or off to one side (offset)? Are the spokes longer on one side than the other? Look at the hub and look at how each spoke alternates - one in one out. Are the spokes thicker at either end? Can you see any thread by the nipple? Does the rim have eyelets? And the important points for the build - where is the valve hole? Where do the spokes cross over? Over two spokes and under the third or is it the fourth?

At this point I should mention that I'm going to gloss over some really basic terminology and techniques, so if you are a complete novice, then I would suggest having a look at Sheldon Brown's wheel building pages for a more comprehensive overview of the whole process.

Backwards – taking a wheel apart

Now that you have inspected your wheel let's take it apart. If you are doing this with a wheel from your bike, you do so at your own risk. If it's a rusty one, then it won't work either, unless you have loads of WD40. You won't have the wheel for reference either so make some notes, or better yet take some photos. You're going to need a few drops of oil and a spoke key/wrench, oh and a wheel truing stand. And some wire bag ties.

Make a note of where the position of the valve hole relative to the spokes. Do the spokes cross directly under the hole? If the rim is offset, then to which side of the hub is the spoke attached? Or take photos with your digital camera so you have a reference on screen. Now with the bag ties, wrap the wire around the spokes at each crossing point. At least a couple of times around so that they won't undo when you remove the nipples. But not so securely that they take ages to remove when you have put the wheel back together. So that's what we are going to do, a rebuild. It's also handy to have a coffee jar lid or small saucer to store your nipples. Dead easy to lose they are.

Put a drop of oil on each spoke/nipple junction and give it a couple of minutes to soak in. Wipe off any excess. And with the spoke wrench, loosen each nipple a few turns. Loosen one, then the next and so on, rather than one the whole way, then the next. Keep going until the nipples are almost off. Now check those bag ties - will they hold?

With the wheel positioned in the truing stand gradually remove each nipple and carefully remove the rim. We're going to put it back together in a bit, so you don't need to take the rim out from between the stand and the hub. Have a look, this is basically the three-cross method backwards, and that was how I discovered it, by doing a rebuild. If you take a new hub and new spokes of the correct length and then put them alternately into the hub, in and out on either side, followed by crossing them and tying them, you should end up with what you have before you now. Then it's just a case of tensioning and truing.

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Putting the wheel back together – wheel rebuild

Now put the wheel back together. Can you remember which spoke went into which hole? Was there a crossing of the spokes under the valve hole? Have a go.

You have 2 things to think about, tensioning and truing. In an ideal world each spoke is exactly the same thickness and has the same elasticity and the rim is perfectly round. But we can't assume that. Which means that each spoke won't be at the same tension. The idea is to get the spokes as tight as possible without stripping the threads. So alternate between tensioning and truing. So, pop a nipple through the hole and give it a few turns, only a few. Keep going till all the nipples are loosely attached to the spokes.

Did you drop any into the gap between the layers in the rim? Yup, it happened to me too. Ok, now concentrate, because this next bit needs it. If you're in a restless mood, leave it for another time.

Go around and tighten each nipple just one turn. I know, they are still really loose, shouldn't I just give them a few more turns? No. We want to try and get that rim perfectly round by tensioning the spokes. So go a little at a time. If you are not in a focused mood you'll make a mess of this part. Keep going, just one turn at a time until the wheel just starts to firm up. Then you need to work on truing.

Truing comprises of three variables: concentric, lateral and dishing. Again, I'm not going to going into that here, but you can find detailed instruction on Sheldon Brown's page, or do a google search for wheel truing. Once you have trued the wheel, then tension again. Just go around each spoke and make each one turn tighter. Check truing, then tension again. Then you go round and squeeze each pair of spokes with your hand or twist them with a screwdriver or something. Again more details on the other page. True the wheel again. That's about it. If you had used your existing bike wheel, then you have rebuilt it and it should be truer and stronger now. A bit like having a new wheel.

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Building a new wheel, 3–cross pre–cross in detail

Well, that was backwards, to give you an idea of the method. Beginners need to read up a bit first, but you'll learn more by just having a go. Experienced builders will have got the idea by now. Ok, some pics. Click any picture to view an enlarged version.

wheelbuilding parts (left)

wheelbuilding tools (right)

So this is what we are starting with. The parts comprise of the hub, the spokes, the nipples and the rim tape (not shown). And the tools as labelled in the picture above. The wheel truing stand is also required which you will see in later pictures. The spoke lengths have to be of the correct size depending on your crossing pattern. You need to calculate this accurately before you order your spokes. The best one is a spreadsheet by Damon Rinard.

As for the tools the nipple clamp is handy so that you don't drop your nipples in between the layers in the rim. The kitchen paper is to wipe off the excess oil that you put on the nipples and the screwdriver is so that you can tighten the spokes through the hole in the rim, which is quicker than using the spoke key. You also need a wheel truing stand. Don't get an entry level quality one. Get a mid-priced one. If you are only going to build a few wheels, get one second hand on ebay and then sell it again. You'll get your money back. Beginners keep your "backwards" test wheel handy for comparison.

every other hole threaded (left)

all holes threaded (right)

This part is dead easy. Drop a spoke through every other hole as shown above left. Then pop all the other ones through. One in, one out. Check it. Check it again. If this part is wrong, you'll have to take it all apart and start again. Yes, it has happened to me, because I didn't check.

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a few spokes crossed and tied (left)

all spokes crossed and tied (right)

In this example the wheel is going to be three cross. So it's three-cross, pre-cross. Have a look at the left picture. Can you see that it goes over two and then under one? And the spokes on the inside are all pointing to the right and the on the outside to the left? I've put the hub in the stand for easy access. Keep going all the way along one side of the hub. Over two and under one. Then the same one the other side. All the spokes on the inside should be almost parallel with the spokes on the inside of the hub on the other side. Can you see that in the second picture? Remember, tie them tight enough to hold, but not so tight that they are difficult to remove later.

Check it. You need to check, so you don't have to take it all apart later on. Look at it from a distance - are all the tips of the spokes the same distance from the hub? Does it look like a circle? Now you are where you left off in the backwards exercise, if you did that. Now before you put the rim in position, oil them tips.

a drop of oil at the end of each spoke (left)

all nipples attached (right)

So what's the deal with the oil? When the wheel starts to reach higher tensions it makes it easier to turn and also makes truing easier at a later date. And why have I attached all the nipples and I'll have to take them off again later? So I don't need to reach around and find them, but you can have them in that coffee jar lid if you want. It also means that the oil stays on and coats the inside of the nipple as well. Put them on only a few turns, just so they stay on, but will come off fairly easily. A quick twist and they are off. Pop the spoke through the rim and a few turns back on.

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attaching the nipples (left)

all the nipples attached (right)

Now before you go popping the spokes through the holes in the rim, 2 things to check - the position of the valve hole and the rim offset.

If it's three cross, then the spokes don't cross under the valve hole. Have a look at the other wheel if you're not sure. And the spokes on one side of the hub attach to the hole that is nearer.

If you have a rim with offset holes you may notice that the holes slightly angled for better entry. Remember, only a few turns, just so they stay on. If you find that it's really loose, then go about halfway along each spoke thread. Use the nipple clamp if you are worried about using your nipple in the gap between the layers. It's tricky to get it out again. I'm using a Mavic MA3 rim here, where you can lose your nipple in the gap. Mavic Open Pro are a good choice because the gap is sealed.

tensioning (left)

truing the new wheel (right)

Well, we're almost done. Not quite actually, because this part takes the longest. In the tensioning picture you can see that I'm using the screwdriver because it's much easier than the spoke wrench for more than one turn. Go for 2 whole turns per spoke all the way round. If it's firm, then start truing, otherwise go round again. When is it firm? When you have to use the slightest force to turn them.

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So, now alternate between tensioning and truing, until the wheel is perfectly round and the nipples are as tight as you can get them but without any danger of stripping the threads. Then you squeeze pairs of spokes in order to pre-stress them. This will put it out of true, but true it again until squeezing doesn't put it out of true. Beginners, does it look anything like the reference wheel?

And there you have it really. Stick on the rim tape, add the tyre and tube. Now you're ready to ride. Scared? Just go for a ride around the block if you are. If you hear "tinkling" noises that's where the spokes are untwisting. Jump on and off a few kerbs just to stress that wheel a bit more. It should be fine if you have followed the instructions as outlined. If you are worried, take it off and check the truing again, otherwise take it to your bike shop and have a mechanic look at it. Happy riding!

Checklist

During the building of my last wheel in July 2006 I made a list of all the steps that I took. Which I think will serve as a summary.

  1. Spoke lengths 1mm less for 3x or 2mm less for 4x
  2. Thread all the spokes
  3. Cross and tie
  4. Bend at hub, inwards
  5. Find correct valve hole position (3x only) and check offset of eyeholes
  6. Tiny drop of oil and 5 turns of each nipple
  7. Give each nipple 2 full turns
  8. Remove ties
  9. Give each nipple one turn and continue until firm
  10. Concentric truing (rough)
  11. Tensioning, one turn each
  12. Lateral truing (rough)
  13. Dishing
  14. Stressing, hands only, squeeze pairs of spokes
  15. Lateral truing
  16. Tensioning, one turn each
  17. Concentric truing
  18. Tensioning, one turn each
  19. Lateral truing, fine, using ¼ turns or less
  20. Stressing with screwdriver or dishing tool
  21. Tension again if loose and true
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