Apologies, this is bit of a long post. Get yourself a coffee if you're interested 
I've been on bit of a journey with this wheel, but I guess we bump into moments when we're 'ready' to tackle something. I love the bike, I think one of the best I've had, so I am keen to look after it - at least until we told to stop riding altogether, which seems to be out there in the horizon. Don't get me started!
Anyway, I think this is one to share since others of you may consider taking it on too.
This journey started because for the last two years the bike has suffered vibration at around 130kmh. I ride to Italy regularly from London, via various routes to stop by friends. But it has reached a point where I could close my eyes and guess my precise speed based on the 'micro vibes'. I also worried about what this was doing to the suspension! I reached a point where it just had to be fixed. When inspecting the wheel, with the tyre off and on the truing jig, I found: radial run-out around 1.8-2mm across 1/3 of the wheel dia. Axial run-out was wavey and averaged 1.8mm both sides of the centre line. BMW spec states 1.7mm in any direction.
I have finished: 0.5mm radial run-out approx. (No more than 0.8 - the videos will explain why I can't pin it down). Axial run-out 0.6-0.8mm. it looks good on the jig too, spokes have a good tension on the spokes and the rim is central in the hub
I have a long history of cycling and building my own wheels for years (admittedly that was some years back now, but it's all in the lexicon). So taking on this job wasn't outside my interest. Like you, I've read plenty about how 'complicated ' or 'difficult' the BMW cross spoked wheels were, up to the point people were refusing to touch them. For some reason that never put me off
YouTube has of course been invaluable. Lots of (incomplete) information. But perhaps the single most useful thing I bumped into was the Skylar Tools "TruSpoke" tool. There was a little connection for me here because it fitted with a similar idea I had - but there were doubts in my mind with my own ideas, which I will share later as they are poignant. What I viewed was sufficient for me to buy the tool. They ain't cheap. So the job was on.
This text is best read in conjunction with the video. I miss lots here and in the videos. Hopefully between them all it builds a useful picture.
I think I will keep things simple and just list the tools and then the process. Following that, I will add some poignant notes since they will make sense of you've held on that far.
TOOLS
• truing jig - not a balancing jig. There is a difference. They are cheap (under £50 GBP). I printed some stops so the spindle came to a rest on them one side it trundled over to)
• Flat turntable about 500mm dia. It's not totally essential, but it does reduce damage to the disc lugs if you're working on a front wheel. And it's just easier. It will get a lot of use in this work!
• Dial guage(s). I don't recommend digital guages, but it's your pref. Use what you're used to.
• Magnetic guage stand to mount into the truing jig.
• Skylar Tools "TruSpoke Tool". It's not cheap! But it is invaluable. I could see that, hence it was the tool or the gamble of a 'new' when from a breaker...
• A small battery drill and some long reach torx bits (T40 to be precise). It really speeds up loosening the spokes - you will be doing it a few times
. I wouldn't recommend it for removing the grub screws - just be patient and make sure the Allen key is properly seated before turning it.
• Some 0000 wire wool. Great for cleaning the nipples - see below for the reasons - also great for cleaning the spokes at the end of the job when you wash it all down (tpms sensor removed!).
• Various coloured making tapes. Now I wouldn't need to mark the spokes. My head is tuned into what matters and where. But in the beginning, it's super useful to mark the spokes into quadrants along with the valve position as the base datum.
• Patience and being methodical.
THE PROCESS (that I used)
• Remove the tyre and discs.
• Remove all the grub screws from all the nipples.
• Get the wheel, without tyre and discs, onto the jig and video it spinning. Video the sound of the spokes when an Allen key (or something else, just stick with the same tool/thing throughout!).
• Using the TruSpoke tool, very carefully measure all the spokes distances and carefully recorded them all - RH side, inner and outer nipples, LH side, Inner and outer nipples. If you're new to the tool, it's is quite accurate and it's something you quickly learn how to use consistently. ***These measurements you take at the beginning, before adjusting anything, are essential/critical with this method.
• Time to be brave. Get the battery drill with your T40 torx bit, and release all the spokes so the rim is rattling on the spokes.
• One by one, remove every nipple and clean it and its seat. Mine needed cleaning as I had touched a little ACF50 onto each nipple/grub screw the night before (glad I did). This job will help the nipples turn accurately, though I didn't entirely trust even this, so I added a stage at the end.
• Using the numbers taken at the very beginning, get an average of each side - for example, get the average of all the RH inner nipples.
• With the wheel off the jig and on the turntable, methodically tighten all the spokes to within 1mm of their average.
• Next, methodically tighten all the spokes within 0.5mm of their average.
• Next, as above, now tighten all spokes to within 0.2 of their average
• Put the wheel back onto the truing jig and using the dual guage(s) check axial and radial run-out.
• In my case, I had spokes that were obviously too loose, despite following the numbers. Now it is their turn to have their slack taken up and made to sound/ring as per their neighbouring spokes - while doing this, constantly check the run-out.
• By now, things should be close. This next stage is an exercise in listening to the spoke tension. In my case, I tried using a torque gauge but I was doing what I'd heard on YouTube, it went against my gut and...it didn't work. I had to start all over again (you'll get used to that
). So I chose to use sound, because by this point I already know the spokes are very close to their original tension - based on the numbers taken before anything was adjusted!
• The final stage is to listen very carefully to all the spokes while constantly checking the dial guage. A HUGE tip is to tighten/loosen the spoke nipples by only 1/32 - 1/16th - it will seem like nothing, but I promise you, you are actually making a change.
• The last thing I did - this was entirely my own idea - I took the wheel off the jig and when it was on the floor, standing on a cushion, I GENTLY tapped the rim with a rubber mallet, then put it back onto the jig. The intention was to release any sticky rotations/positions of the nipples. Then check again with the guage(s).
• if after all that you are happy. Refit the grub screws to 3Nm.
To some extent, it's taken me longer to write all this. By the last iteration , I could get it all done in under 2hrs, from rattling rim to finished spoke tensioning.
The TruSpoke tool measures the depth/reach of the spoke into the nipple. By meeting them all before you begin, you have a very good ready reckoner on where you should be finishing. My original thinking was, all the spokes must surely be the same length to make this work?! I'm practice it's more about knowing where the average is than trying to become uber precise. The tool gives you a reliable and repeatable way to turn to 'known' positions. Without it, skilled nuisance takes over, but I don't plan to become a wheel builder
. Despite what I say in the videos, I can now see how this tool would work if you re-laced the wheel, but I see numerous attempts needed to firm a baseline for the till to come into it's own.
Having the rim rattling on all the spokes is when you know you're committed to the job
.
My wheel is now finished. It was the 4th iteration - so I loosened of the spokes three times. By that point, you have very definitely begun to get into it
Obviously it takes the right timing, right kind of person and having a space to work in. Patience, being gentle as opposed to hasty and of course, methodical, using ref points, sticking with them and being honest with yourself when it's a pile of crap
Hoping this has been of use. Happy to answer questions. Video link below is this evening. I have more and will post soon. Just need to get on with all the other things I've been neglecting!
- the videos are a little rough and unplanned, but I suspect will be useful to others
Sent from my SM-S908B using Tapatalk

I've been on bit of a journey with this wheel, but I guess we bump into moments when we're 'ready' to tackle something. I love the bike, I think one of the best I've had, so I am keen to look after it - at least until we told to stop riding altogether, which seems to be out there in the horizon. Don't get me started!
Anyway, I think this is one to share since others of you may consider taking it on too.
This journey started because for the last two years the bike has suffered vibration at around 130kmh. I ride to Italy regularly from London, via various routes to stop by friends. But it has reached a point where I could close my eyes and guess my precise speed based on the 'micro vibes'. I also worried about what this was doing to the suspension! I reached a point where it just had to be fixed. When inspecting the wheel, with the tyre off and on the truing jig, I found: radial run-out around 1.8-2mm across 1/3 of the wheel dia. Axial run-out was wavey and averaged 1.8mm both sides of the centre line. BMW spec states 1.7mm in any direction.
I have finished: 0.5mm radial run-out approx. (No more than 0.8 - the videos will explain why I can't pin it down). Axial run-out 0.6-0.8mm. it looks good on the jig too, spokes have a good tension on the spokes and the rim is central in the hub

I have a long history of cycling and building my own wheels for years (admittedly that was some years back now, but it's all in the lexicon). So taking on this job wasn't outside my interest. Like you, I've read plenty about how 'complicated ' or 'difficult' the BMW cross spoked wheels were, up to the point people were refusing to touch them. For some reason that never put me off

YouTube has of course been invaluable. Lots of (incomplete) information. But perhaps the single most useful thing I bumped into was the Skylar Tools "TruSpoke" tool. There was a little connection for me here because it fitted with a similar idea I had - but there were doubts in my mind with my own ideas, which I will share later as they are poignant. What I viewed was sufficient for me to buy the tool. They ain't cheap. So the job was on.
This text is best read in conjunction with the video. I miss lots here and in the videos. Hopefully between them all it builds a useful picture.
I think I will keep things simple and just list the tools and then the process. Following that, I will add some poignant notes since they will make sense of you've held on that far.
TOOLS
• truing jig - not a balancing jig. There is a difference. They are cheap (under £50 GBP). I printed some stops so the spindle came to a rest on them one side it trundled over to)
• Flat turntable about 500mm dia. It's not totally essential, but it does reduce damage to the disc lugs if you're working on a front wheel. And it's just easier. It will get a lot of use in this work!
• Dial guage(s). I don't recommend digital guages, but it's your pref. Use what you're used to.
• Magnetic guage stand to mount into the truing jig.
• Skylar Tools "TruSpoke Tool". It's not cheap! But it is invaluable. I could see that, hence it was the tool or the gamble of a 'new' when from a breaker...
• A small battery drill and some long reach torx bits (T40 to be precise). It really speeds up loosening the spokes - you will be doing it a few times

• Some 0000 wire wool. Great for cleaning the nipples - see below for the reasons - also great for cleaning the spokes at the end of the job when you wash it all down (tpms sensor removed!).
• Various coloured making tapes. Now I wouldn't need to mark the spokes. My head is tuned into what matters and where. But in the beginning, it's super useful to mark the spokes into quadrants along with the valve position as the base datum.
• Patience and being methodical.
THE PROCESS (that I used)
• Remove the tyre and discs.
• Remove all the grub screws from all the nipples.
• Get the wheel, without tyre and discs, onto the jig and video it spinning. Video the sound of the spokes when an Allen key (or something else, just stick with the same tool/thing throughout!).
• Using the TruSpoke tool, very carefully measure all the spokes distances and carefully recorded them all - RH side, inner and outer nipples, LH side, Inner and outer nipples. If you're new to the tool, it's is quite accurate and it's something you quickly learn how to use consistently. ***These measurements you take at the beginning, before adjusting anything, are essential/critical with this method.
• Time to be brave. Get the battery drill with your T40 torx bit, and release all the spokes so the rim is rattling on the spokes.
• One by one, remove every nipple and clean it and its seat. Mine needed cleaning as I had touched a little ACF50 onto each nipple/grub screw the night before (glad I did). This job will help the nipples turn accurately, though I didn't entirely trust even this, so I added a stage at the end.
• Using the numbers taken at the very beginning, get an average of each side - for example, get the average of all the RH inner nipples.
• With the wheel off the jig and on the turntable, methodically tighten all the spokes to within 1mm of their average.
• Next, methodically tighten all the spokes within 0.5mm of their average.
• Next, as above, now tighten all spokes to within 0.2 of their average
• Put the wheel back onto the truing jig and using the dual guage(s) check axial and radial run-out.
• In my case, I had spokes that were obviously too loose, despite following the numbers. Now it is their turn to have their slack taken up and made to sound/ring as per their neighbouring spokes - while doing this, constantly check the run-out.
• By now, things should be close. This next stage is an exercise in listening to the spoke tension. In my case, I tried using a torque gauge but I was doing what I'd heard on YouTube, it went against my gut and...it didn't work. I had to start all over again (you'll get used to that

• The final stage is to listen very carefully to all the spokes while constantly checking the dial guage. A HUGE tip is to tighten/loosen the spoke nipples by only 1/32 - 1/16th - it will seem like nothing, but I promise you, you are actually making a change.
• The last thing I did - this was entirely my own idea - I took the wheel off the jig and when it was on the floor, standing on a cushion, I GENTLY tapped the rim with a rubber mallet, then put it back onto the jig. The intention was to release any sticky rotations/positions of the nipples. Then check again with the guage(s).
• if after all that you are happy. Refit the grub screws to 3Nm.
To some extent, it's taken me longer to write all this. By the last iteration , I could get it all done in under 2hrs, from rattling rim to finished spoke tensioning.
The TruSpoke tool measures the depth/reach of the spoke into the nipple. By meeting them all before you begin, you have a very good ready reckoner on where you should be finishing. My original thinking was, all the spokes must surely be the same length to make this work?! I'm practice it's more about knowing where the average is than trying to become uber precise. The tool gives you a reliable and repeatable way to turn to 'known' positions. Without it, skilled nuisance takes over, but I don't plan to become a wheel builder

Having the rim rattling on all the spokes is when you know you're committed to the job

My wheel is now finished. It was the 4th iteration - so I loosened of the spokes three times. By that point, you have very definitely begun to get into it

Obviously it takes the right timing, right kind of person and having a space to work in. Patience, being gentle as opposed to hasty and of course, methodical, using ref points, sticking with them and being honest with yourself when it's a pile of crap

Hoping this has been of use. Happy to answer questions. Video link below is this evening. I have more and will post soon. Just need to get on with all the other things I've been neglecting!
- the videos are a little rough and unplanned, but I suspect will be useful to others

Sent from my SM-S908B using Tapatalk