The Quintessential BMX Wheelbuilding Guide

I’ve laced up a fair few wheels in my time and always felt tutorial videos always fell a little short in the way that there’s just so much more to our wheels than meets the eye.  So without making too much of a song and dance I’m going to pass on to you, O’ faithful The Merged reader, pretty much everything rattling around my cranial cavity on the subject of building BMX wheels.  Stick the kettle on…

Yep… (pic nicked from Google)

Safety First.

Building wheels is potentially extremely dangerous and life threatening if done without caution.  The amount of tension stored within a single spoke can often exceed 150 kgf- effectively turning every spoke in your wheel into a makeshift crossbow bolt.  If one of those spokes gives way suddenly at the j-bend and there’s nothing to stop it, it will fire out of the rim and through anything in it’s path.  A fired spoke can very easily impale your hand so it can and will do the same to your brain if a spoke fires toward your eyes.  When working on your wheels, you must always have a decent rim strip on at the bare minimum, a tyre left on the rim isn’t a bad thing either.  If you have neither of these or can’t use them because you need to use a nipple driver, wear eye protection (your granddad’s angle grinder googles will do) and never look directly into the rim cavity while tightening spokes.  Now that I’ve scared the living shit out of you, let’s build!

A Yellow Spokey spoke key. The best around for the money (pic nicked from Google)

Tools.

You don’t really need too much to build and maintain a wheel, if you’re on a budget a spoke key of some description, a frame/fork (dependent on whether you’re building a rear of front wheel) with a zip-tie around the chainstay/fork leg and internet access are the bare bones of what’s required.  Spoke keys come in a variety of different types and sizes, while most BMX companies put out some kind of key ring style 3.5mm 3-sided spoke key, these are to be used with care as they’re not always a great fit and can round off nipples if used haphazardly. A classic go-to spoke wrench is a yellow (3.4mm) Spokey as it’s cheap and has 4 sides for decreasing the chances of rounding anything off.  Some people also like to use a flat head screwdriver or a modified phillips head as a nipple driver to access the nipple from inside the rim cavity.  This can save you a bunch of time and keeps those nipples looking a bit fresher on the outside where spoke keys can sometimes take anodising off.  While a Parktool TS2.2 wheel stand will always be my personal weapon of choice for truing wheels, I managed just fine for years with a neatly trimmed zip tie around an old Pantera frame I have laying about, you’ve just gotta make sure you tighten the wheel nuts before starting any work.  Dishing accurately is pretty hard to do in a frame but you can usually line up the rim pretty well by eye if you use the fork crown or stay bridges as a visual guide.  The less clearance you have for your fat tyres within your frame or fork, the more accurate you’ll have to be.  Just note that even if you do dish the wheel to be as central as humanly possible, you may still have clearance issues if you run 2.5″ tyres in a regular non-widened stay/bladed-ed frame or fork.  For example, Cult AK tyres coupled with Odyssey R32 forks will probably have clearance problems due to tyres rarely, if ever, being perfectly round and the R32 forks not being designed for the ridiculously wide tyres found in some company’s catalogues.  You’ll need the internet access for using an online spoke calculator, Waller’s is the most up to date and Pijin’s calculator is good for some older models of hub and rim.  Other than that all you’ll need is a little ‘3-in-1’ style thin oil if you have it, a load of patience and some free time…

A section of an Eclat Tripin rim. Notice the thicker outer walls reinforcing where the nipples put the most tension, and the holes are offset to either the left or right and not central.

Rims.

When going over the specs of rims on offer to them, some might be inclined to go with the most expensive thing on the list, the all-bells-and-whistles internally reinforced 70-something, something-T6 alloy flash welded hoop in the hope it’ll last longer than something 40 quid cheaper.  This assumption is only half correct.  While superior materials and manufacturing techniques do help, the longevity of your wheels relies almost entirely on you and how much (and how effectively) you maintain your wheels.  With that said, what does matter when it comes to rim design?  The main two factors are probably spoke hole offset and spoke hole reinforcement.  Spoke hole reinforcement is important for nipples that endure massive loads from super tight spokes and may otherwise distort or even pull through the rim wall.
Spoke hole offsetting is to decrease leverage on the rim.  If you imagine a model pyramid on your desk with the top cut off and a cup of water placed on top of it, the more that’s cut off the top (increasing the surface area) the harder it is to topple the water off the pyramid.  If the four points of the top of the pyramid represent four spoke holes in a section of the rim and the cup of water is the section of rim itself, it’s easy to see the importance of having a decent amount of spoke offset (more cut off your pyramid) to keep side-loads from putting a rim out of true.  However if you leave your spokes to loosen, or simply periodically tightening spokes indiscriminately without checking how true the rim is, your rim will fail to keep it’s shape (no matter how much you spent on it) and probably turn into something reminiscent of Ben Lewis’s wheels circa 2002 a lot quicker than you’d hope…  So to reilliterate, a hundred quid rim will only last you longer if you look after it properly by keeping the spokes tightened evenly and trued regularly.  At this point I should point out that when I say ‘regularly’ I specifically mean the following;

1. Every 1-2 days for the first fortnight of the wheels life.
2. Every week for the next 2-3 months of the wheels life.
3. Every 2-3 weeks after that until the wheel is retired.

Think of spokes as living muscles that need to be ‘warmed up’, you can’t just whack some spokes in the wheel, wrench them up to the max and be done with it, you have to ease them into their optimal tension evenly and slowly or the rim will buckle faster than you’d expect.  It does happen though, and in that event you need to know about….

What I see on the back of my eyelids when I go to bed at night… (pic nicked from Google)

Truing.

Truing is an easy skill to learn but a hard one to fully master, no amount of reading wheelbuilding guides will ever get you good at truing, only practice will do that so the best way is to have a pop at an old wheel with a buckle in it.  This section should be considered a very basic rough guide to start you off as it would probably take me another 5000 words to fully explain…
Firstly as you rotate the wheel in your stand you need to identify the center line in which your rim should be.  To do this, you simply need to see where most of the rim spends most of it’s rotation before the buckle causes it to briefly veer off to the left or right.  Once you identify where the rim should be, finding the individual buckles will be a lot easier.  Move the caliper (or zip tie) of your stand closer toward your spinning rim until you hear/see a tiny scrape of the buckle hitting it; this is the apex of the buckle and you should keep it’s exact place while you pick up your spoke key.  If the closest spoke to the buckle’s apex is on the opposite side of the hub/rim, you can tighten that spoke to try and pull the rim back to the opposite side, to counteract any extra tension on this section of rim it’s wise to loosen off the two spokes on either side of the spoke you tightened.  For example, if you tightened the spoke by half a turn, you would loosen the two either side by a quarter.  If the spoke closest to the buckle apex is on the same side of the hub/rim, the same principle applies except you would loosen that spoke and tighten the two spokes either side of it.  Once you’ve finished the adjustment, move the calipers in slightly, spin the wheel and look for the next worse buckle (and repeat)
Radial truing is a little harder as BMX wheels are so much more rigid than other bike wheel types. Firstly check your spoke tension by squeezing handfuls of four spokes around the wheel.  Chances are if you don’t get more than a couple of millimeters of movement, you may need to go around de-tensioning each spoke evenly by a turn to make the rim more malleable. Once that is done, instead of using the calipers on your stand (or zip ties on your stays) to find side-to-side (lateral) buckles, you position it below and use it to find up-and-down (radial) buckles; commonly known as an ‘egg’.  When you find the lowest point of the rim, much in the same same way you find the apex of a lateral buckle, tighten the closest four spokes to the lowest point (they will more than likely be much looser that the rest) to ‘pull’ that section toward the center of the hub.  Counteract any unnatural tensioning by loosening the 4 spokes on the opposite side of the wheel (which will be the point of the rim that’s furthest away from the caliper) to ‘push’ that section away from the center of the rim.  Just remember that you may need to go over your work a few times before you start seeing the results you want, even going as far as to go back and forth between radial and lateral truing a few times.  My rule of thumb is ‘fix the worst thing first’… Once everything is nice a true; or at least as true as it will ever be, go around the wheel re-tensioning each spoke an equal amount to lock it all in place.

36 hole flangeless front hub- made for 4 cross lacing patterns.

Hubs.

There’s not much to say on this subject other than covering the different flange set-ups available on BMX hubs which are; even flanged, high drive-side flange and flangeless.  Even flanged hubs (typical of front hubs and some cassette hubs) are easiest to build and tension being that both sides of the hub flange are evenly sized.  High drive-side flanged hubs (typical of most high-end cassette and all freecoaster hubs) take a little more care in being tensioned as one flange is bigger than the other, effectively lengthening the drive side spokes.  This requires a technique called dishing in where the drive-side spokes are tightened more than the non-drive side spokes to compensate and centralise the rim over the hub.  Flangeless hubs are simple to tension much like the even flanged variety of hub but due to their streamline design lacing is slightly more fiddly if you don’t know in what order to lace it up… I’ll get to that shortly.

Diagram showing correct nipple use (pic nicked from Google)

Nipples.

Brass? Aluminium? We could debate this all day as there are pros and cons to both but we both know you’re probably just going to use whatever came in the pack of spokes you ordered from Win-fuckin’-Stanleys anyway you cheap assface.  The only real noteable part of the nipple that I can give any real advice over is this; try and keep the spokes you use as long as humanly possible- but not poking through so you get a hole in your rim strip and a subsequent puncture; just enough that you have to switch from using a nipple driver to a spoke key.  The higher in the nipple the spoke thread is, the more reinforced the head of the nipple is and less likely the nipple will break off under high tensions.  Sometimes this isn’t possible if you buy spokes that are too short, but if you use a spoke calculator it should be easy to get the right length spoke.

Double butted spokes like this are thicker at the ends and thinner in the middle. (pic nicked from Google)

Spokes.

In an ideal world I’d build every wheel with DT Swiss Competition spokes but being the best spokes in the world can make them a right pain in the nutsack to get hold of in certain places as they’re just so popular.  Most spokes on the market will do the given job relatively well but some will argue that stainless spokes will last longer than black or coloured spokes as anodizing changes the surface of the metal (I’m definitely no expert in metallurgy but I have always noticed any anodised spokes on my wheels always seem to break a lot quicker than any stainless) and even more will argue that straight gauge spokes are not stronger than double-butted (Did you ever see a spoke break in the center?  Yeah, me neither…)  So when you think you’ve nailed two birds by buying cheaper non-butted spokes that you assume will be stronger- all you’ve done is save a couple of quid in return for dragging a few more grams of rotational weight for the next couple of years.  Buy better (if you can) and buy butted…
Online spoke calculators are pretty damn useful in buying the correct sized spokes by simply selecting your rim and hub as well as the desired lacing pattern so take full advantage but most 36h-3x lacing patterns will use something between 182-188mm and flangeless 4x patterns will mostly use 190-194mm spokes.
The question on some people’s lips will be ‘what about titanium spokes?’  My answer to that is to stay the fuckedy-fucking-fuck away from titanium spokes!  They are certainly not the ideal material for spokes, especially not for the gargantuan price tag.  Stick to stainless, trust me.

I’m fucking with you, I’d never ride one of these snowflake patterns and neither should you. (pic nicked from Google)

Lacing Patterns

There are a few lacing patterns utilised in BMX over the years, but it’s generally agreed upon that a 36 holed hub with flanges should be laced 3-cross (each spoke overlaps 3 other spokes on the same side of the wheel, interlacing the last spoke) for freestyle.  Some shops and even some companies will occasionally build wheels with flanged 36 hole hubs 4-cross but this is seen on the whole as a faux-pas as the ‘j-bend’ of the spoke ends up resting over the top of the spoke head next to it.  This creates an unnatural and undesirable bend in the j-bend creating a kind of pulling effect on the heads of the spokes often severing it from the rest of the spoke.  Not only this but 4-cross makes it extremely fiddly to replace broken spokes.  If you’re ever getting a shop to build your flanged wheels, insist upon 3-cross before ordering.
Where the 4-cross pattern really excels is on flangeless front hubs like Fiend, Eclat, Primo, Simple etc. The extra triangles formed in the wheel by the extra spoke crosses and the lack of flanges keeping the spokes as straight as possible make this lacing pattern the strongest (yet probably heaviest due to needing longer 192-194mm spokes) pattern for 36h, ideal for anyone who is super abusive with their front wheels.  Kis do/did a cassette hub that has a hybrid flanged drive-side and flangless non-drive-side which would require 4-crossed 190-4mm spokes on one side and 3-crossed 182-8mm spokes on the other.  The Kis hub sounds like a bit of a hassle but it’d make a great lacing pattern for a rear wheel.  48 spoke wheels use 4 cross too but use the same length spokes as a typical 36h wheel- the extra crosses are simply due to there being more spokes… If 48’s are still your thing read GSport George’s wheelbuilding guide for an in depth look at how 48’s should be laced… which isn’t that different to 36’s but it was the first wheelbuilding guide I ever read so I kinda feel like I should plug it a little.  Tree’s straight pull hubs go a step further and go up to 36 hole 5 cross, but they use straight pull spokes and race style flanges to squeeze an extra set of spoke crosses in- but it will lace up much like a flangeless hub does.

Bicycle blood. (pic nicked from Google)

Prep.

Once you’ve acquired all your tools, a rim, a hub, a set of spokes and nipples, take the oil and pop some into an old bottle cap to dip the spoke threads in.  This will make everything a bit smoother and predictable when putting the wheel together and will help combat corrosion inside the nipples as the wheel gets older and exposed to moisture. Speaking of preparation, this would be a good time to make that cup of tea and have a piss as it will be your last opportunity to do so until your wheel is laced.

Valve Hole Vision.

Choose the first spoke carefully if you want the logo to line up with the valve hole.

VHV is an aesthetic step where you lace a wheel with the hub’s logo facing the valve hole.  This has absolutely zero effect on a wheels performance but is used as a visual aide to find the valve hole quicker and simply shows the wheelbuilder pays attention to the smallest of details.  To do this you have to put the first spoke in at a specific hole to line up the logo. The way I tend to do it is with the drive side facing up, put an inward bound spoke (these will be the leading spokes) through the third or fourth spoke hole to the left of the hole that falls adjacent to the center of the logo.  Twist the hub backward- the same direction your driver goes when back pedaling- to simulate the final position and check the valve hole and hub logo line up- if not move the spoke along one flange hole, or even try beginning on the non-drive side as spoke holes are offset to the ones on the opposite flange.  Logos on hubs are not always lined up exactly the same from brand to brand but you can always get a half decent result if you put some time into this step.  Alternatively you can skip this step completely, pop an inward facing spoke into a random hole on the right hand/drive side (I always start on the right side, it’s just easier to remember) and move onto the following guide… Just know that the final position of the hub in relation to the valve hole is determined entirely by the first spoke.

Valve hole vision

36 hole flanged hub with 3-cross lacing

Step 1. Place the rim on your lap with the valve hole opposite you.  The valve hole is your reference point at which you’ll start and finish each ’round’ of adjustments, never stop half way or you will lose your place.  It’s also very important you follow these beginning steps closely otherwise you might find your self with a perfect wheel but with the valve hole inside a section of four spokes with no room for a pump.  It sounds like an easy thing to avoid but I’ve seen plenty of people hashing it up in this exact way.

First right hand inbound spoke laced to left of valve hole

2. Put a spoke through a hole from the outer side of the hub so the spoke is on the inside of the drive-side hub flange with the spoke head facing outward.  This is what is referred to as an ‘inbound spoke’ and you start with these because they are harder to install once the outbound spokes are in place.  Take that first spoke and lace it to the first hole to the left of the valve hole and thread on a nipple, not all the way, just enough that it isn’t going to come loose and roll under the sofa.  You should thread on all the nipples like this initially.

Second inbound spoke laced 4 holes from the first

3. Take another 8 spokes and put them through the hub flange the same way as the first, leaving one empty spoke hole in between each spoke you put into the hub, the remaining holes will be for the ‘outbound spokes’.  The rim holes you lace these up to should be on the corresponding side of the rim to the hub flange due to the rim’s spoke hole offset (unless you have a cross-lacing rim like a G-Sport Ribcage in which they’ll be on the opposite side of the rim- this can be confusing at first so take your time and don’t be afraid to go back or even start over if you get lost)

Right hand inbound spokes in place

4. Lace those spokes to every fourth hole on the rim, leaving three empty spoke holes between each spoke.
5. Turn the wheel over.

Wheel turned over
Hub spoke hole offset illustrated

6. Looking directly down at the hub, at the spoke closest to the valve hole you’ll notice that it’s offset and falls directly in between the two spoke holes adjacent, in the flange closest to you.  Drop a spoke in the right hand hole to the aforementioned spoke and lace that spoke in the rim hole to the immediate right of the spoke closest to the valve hole.  You should now have two spokes to the right of the valve hole.

First left hand inbound spoke laced

7. Same as with the other side, put another 8 inbound spokes into the hub flange, leaving a spoke hole between each.
Lace each of those spokes to the rim hole on the right of each of the already attached spokes.

Inbound spokes laced

You should have what kinda looks like a bit like a really flimsy, radially-laced, fixie wheel so far.

8. Now that all the inward bound spokes are in place, it is now easier to put in the outbound spokes from the opposite side.  Flip over the wheel so the drive-side is facing up towards you again.  Imagining the direction the driver would rotate if you were backpedaling and rotate the hub inside the rim in the same direction so the spokes are now angled in the ‘leading’ position.

Hub twisted to angle inbound spokes in leading position

9. Take a spoke and insert it into the hub flange from below so you have an outward bound spoke; any of the remaining holes on the hub flange will do at this point of the build, then angle that spoke (almost) perpendicularly to the inbound spokes and cross one spoke before it clears the flange, another spoke at about 1 cm out from the flange before interlacing it under a third spoke (you will need to bend the spoke a little to do this without scratching your rims up which is completely normal but try not to kink the spoke at all…) and lacing to the second hole from the interlaced spoke remembering it should be on the same side of the rim to the hub…

First outbound spoke interlaced

10. Repeat with another 8 spokes on the same side, it should all be starting to come together now.

Left side outbound spokes laced

11. Interlace the remaining 9 spokes on the opposite flange, feeding the spokes straight through the smallest triangles in the spokes so you don’t have to bend the spokes or scratch the hub shell.  There are only 9 holes remaining in the rim so the lacing up of these spokes should be pretty self explanatory by now.  Albeit a bit loose and bowed in the spokes, you should have a perfectly laced wheel with the valve hole in between two groups of four spokes with plenty of room for a track pump.

First right hand outbound spoke interlaced
Complete!
Correct valve hole position

Tensioning

1. Next you’ll need to thread all the spoke nipples down to a common point- the end of the exposed thread on the spoke is a good place to set it but you may need to leave a couple of threads showing if your spokes are on the shorter side.  Don’t panic if you spin your wheel and it’s not straight at this point, the important thing at this stage is that you keep the spokes tightened evenly and loosely; everything else will come together in the following stages.

2. When all your nipples are threaded onto your spokes an even amount, you’re ready to start bedding in the spokes.  Grab a handful of 4 spokes with each hand, on opposite sides of the wheel and squeeze them together hard to bend them into something that will better resemble their final shape.  If you ever take a spoke out from a used wheel and compare it to a brand new, unused spoke, the j-bend will have much less of an angle than the new one which is why bedding-in is important.  If you tension a wheel a wheel without seating/ bedding in your spokes, there could be slack in the spoke’s j-bend that has yet to be taken up in the initial building process and may leave you with a buckled rim quicker than you’d hope.

3.  Bounce the hub inside the rim for a few moments while the spokes are still loose to try and even out any friction between the rim and spokes.  This will usually make things less labour intensive when it comes to truing the wheel later on.

4.  Put the wheel into a stand and starting with the valve hole, go around the wheel turning each nipple an even 1 turn, even if one of the spokes feels real loose and one feels real tight, that may just be the nipple threads, so just keep things nice and even, remembering to keep track of the position where the spoke key started it’s rotation.  Once you’ve tightened each of the 36 nipples by a single turn, starting at the valve hole again, do the same again.  I say to do 1 turn (of the nipple) per rotation (of the wheel) instead of 2 because it’s a lot more subtle on the rim than just whacking out 2 turns on one rotation, which puts a lot of strain on parts of the rim where there is a difference of 2 turns worth of tension instead of just 1, more likely to shift it out of true.  Maybe add another round of nipple turns if your spokes are on the longer side.  You should now have a little bit of tension in your spokes, enough that the spokes are straighter than before but still a little loose.

5. Once again grab a couple of hand fulls of 4 spokes on either side of the wheel and squeeze around the wheel, bedding in the spokes further.  Once you’ve gone around the wheel a couple of times, the best thing to do is to find something like an old aluminium crank arm (as shown here by the famous Sheldon Brown) or even a similarly sized piece of scrap wood and using it as a lever, pivot it against an outbound spoke and lever up under an inbound spoke to bed it into the hub flange from the inside of the wheel, repeating the process around the wheel.  Some people also like to tap the j-bends very lightly with a claw hammer but taking a hammer to any part of my bike is like nails on a blackboard to me.  This should take out any remaining slack that the j-bends might be storing within it.  To check, spin the wheel and keep your eye on the j-bends by the flange, they should all follow the same bend as each other.  Your wheel is now primed for tensioning and truing.

6. If you have a rear hub with a drive side flange bigger than the other, you’ll have to dish the wheel otherwise it will be one-sided in your frame.  The difference between two different sized flanges is usually about 3 turns of the nipple so with the wheel in a stand, identify the side the rim has to move to (the drive side) and tighten the spokes on that side of the wheel by 3 turns.  Alternatively you can tighten the larger flanged side by 2 turns and loosen the opposite side by 1 turn; as long as there are 3 turns worth of tension between the two sides.  Check the wheel within the stand and adjust accordingly.

7.  Truing is the penultimate step and if you followed the instructions (and are lucky) it shouldn’t take long at all being a new wheel.  See the Truing paragraph at the top of the article.

8. Finally lock it all into place with the final tensioning.  Go around the wheel, beginning with half turns of the nipples initially, converting to quarter turns after a couple of rotations of the wheel.  The easiest and cheapest way of checking tension at this point is simply by going by the resistance the nipple gives you when trying to tighten it; once the nipple starts to get difficult to turn, it’s about time to stop.  Squeezing a handful of 4 spokes like before should only move them by 1-2mm max.  I personally bought a Parktool TM-1 spoke tension meter to test my own wheels, but despite being worth the money if you build a lot of wheels and a great analytical tool, they are far from essential.  Regardless, I found BMX sized wheels tend to work best when the spokes are tensioned to around the halfway ’25’ mark of the TM-1 tool which equates to about 167 kgf (1670N) for 2mm steel spokes.
Please note; While most MTB or Road rims will have a manufacturer-recommended tension rating this is often not the case for BMX so the above figure of 167kgf is largely an estimate, is entirely dependent on the rim’s structural integrity and should be reduced for any budget rims that might otherwise have the nipples pull through the rim wall.

36 hole flangeless hub 4 cross

Simply trying to apply the above wheel building guide to building a 4 cross flangeless front wheel is a recipe for high blood pressure.  The quickest and easiest way to build a 4 cross is to lace the inward bound and the outward bound on one side of the hub; and in that order, before repeating on the other side of the hub.  That way if an inward bound spoke goes astray (and it will, at least once…) before you can get a perpendicular outward bound spoke in to lock them all in place, you only have to unlace 8 spokes instead of 17 of the little bastards… it really makes a difference, if only to your time keeping.
The slight downside to building one side of the wheel before the other is that the wheel will tend to dish to the side you built first rather than be automatically centered like building a normal flanged front hub using the aforementioned guide.  Remedy this by ‘bouncing’ the hub around inside the rim while the spokes are still loose to free everything up a bit.  If the wheel is still out of dish, you may have to tighten all the spokes on the side you want to pull the rim toward a little more than the opposite side.
Being that the spokes are longer, the first spoke that determines the valve hole vision position will more than likely be slightly further to the left of the hub logo than a 3 cross wheel so you will need to adjust that accordingly. Try a few different holes and rotate the hub inside the rim with the first spoke attached to see what works best if you’re unsure about what hub hole to start with.

I think that’s about it. Three months and over 5000 words later, I hope this guide is as useful to you as it was stressful for me to write.  Get rollin’ people.

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