Truing a cross spoked front wheel

Slipperyeel

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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




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Interesting,

not sure whether is was the hand held camera, but the LH seemed to show a slight deviation in the Y axis

or it's the tyre on the rim

either way, bloody good work
 
The penultimate video...




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Interesting,

not sure whether is was the hand held camera, but the LH seemed to show a slight deviation in the Y axis

or it's the tyre on the rim

either way, bloody good work
More videos coming which I hope will explain more. I think what you're seeing is a combination of handheld video and yes, perhaps a little of the tyre.

It's so much better than before I started!

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Another, earlier video in the series. Here the rim is all loose on the spokes. This is essentially your starting point.



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Just Read the whole post and watched the videos, excellent stuff and I don't even have a bike with those wheels.

Get ready for plenty of requests for your services :D or to borrow your tools.
 
A small note on balancing.

BMW states in the specs that neither wheel should have more than 80g (each wheel). I didn't know this until I got onto this job.

The pressure sensor (if you have them fitted) weights around 45g. So before the tyre is even fitted, you'll be adding 40-50g.

Before I began this, my wheel had the full 80g - not sure if that's just luck?!
Now, after carefully balancing it (took a little longer than I imagined), it has just 65g, which is interesting. I think this is because I've always used the fitters, who probably don't give it the time it needs - and if they're using the auto balancer, are they calibrated properly?

Either way, less weight the better.

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Wow. This is excellent.
Thanks for taking the time to explain it all.
 
Just Read the whole post and watched the videos, excellent stuff and I don't even have a bike with those wheels.

Get ready for plenty of requests for your services :D or to borrow your tools.
Thanks!

Wish I could edit the auto complete typos



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Wow. This is excellent.
Thanks for taking the time to explain it all.
Thanks er-minio. Bit of a long post and bit rambling, but I'm hoping it proves useful.

I'm still happy to look at yours sometime

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A small note on balancing.

BMW states in the specs that neither wheel should have more than 80g (each wheel). I didn't know this until I got onto this job.

The pressure sensor (if you have them fitted) weights around 45g. So before the tyre is even fitted, you'll be adding 40-50g.

Before I began this, my wheel had the full 80g - not sure if that's just luck?!
Now, after carefully balancing it (took a little longer than I imagined), it has just 65g, which is interesting. I think this is because I've always used the fitters, who probably don't give it the time it needs - and if they're using the auto balancer, are they calibrated properly?

Either way, less weight the better.

Sent from my SM-S908B using Tapatalk
How does the wheel balance with just the sensor fitted? what weight is needed to cancel it out.

And does the tyre balance then start from 0 with the sensor fitted?
 
How does the wheel balance with just the sensor fitted? what weight is needed to cancel it out.

And does the tyre balance then start from 0 with the sensor fitted?
With just the sensor fitted, 100% of the time, it ends up at the bottom - hence weighing the sensor to give me a clue as to how much was needed to cancel it out (around 45g in my case).

My aim was to have the wheel, with sensor fitted, balanced as best as I could get it. Therefore less weights once tyre was on.
So yes, once the WHEEL is balanced, you begin from zero again with the tyre fitted.

My tyre has no yellow spot on the side wall, so it's a little bit of a gamble. I deliberately rotated the tyre approx 90° from where it was originally fitted (I marked it before removal). So this might also account for less weight needed.

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With just the sensor fitted, 100% of the time, it ends up at the bottom - hence weighing the sensor to give me a clue as to how much was needed to cancel it out (around 45g in my case).

My aim was to have the wheel, with sensor fitted, balanced as best as I could get it. Therefore less weights once tyre was on.
So yes, once the WHEEL is balanced, you begin from zero again with the tyre fitted.

My tyre has no yellow spot on the side wall, so it's a little bit of a gamble. I deliberately rotated the tyre approx 90° from where it was originally fitted (I marked it before removal). So this might also account for less weight needed.

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Its funny you should say that, i was under the understanding that cars have a white dot, and it should be opposite the valve , something to do with the join of the tyre bands/ beads cancelling out the mass of the sensor

But on a lot of cars they are nowhere near, which makes you think, do they just put the tyre on and balance as whole

My local bike tyre place cant balance gs rears as he dosent have a mandrill suitable for his balance machine, so he leaves on any current weights, and puts the dot opposite

haven't noticed any issues since it was done, and its due another set in about 4 weeks time
 
Its funny you should say that, i was under the understanding that cars have a white dot, and it should be opposite the valve , something to do with the join of the tyre bands/ beads cancelling out the mass of the sensor

But on a lot of cars they are nowhere near, which makes you think, do they just put the tyre on and balance as whole

My local bike tyre place cant balance gs rears as he dosent have a mandrill suitable for his balance machine, so he leaves on any current weights, and puts the dot opposite

haven't noticed any issues since it was done, and its due another set in about 4 weeks time
I think you are wrong with this statement.
I was always told the dot should be placed where the valve stem is, it marks the lightest point of the tyre.
If your tyre fitter is putting it opposite he is also wrong.

On another note I often wondered about the weight of a pressure sensor that is fitted and putting an equal amount of weight on the other side. You might think this could cause an amount of rotational imbalance in itself. Surely the amount of weight all round should be near equal?.
Maybe I'm overthinking this 😁
 
I think you are wrong with this statement.
I was always told the dot should be placed where the valve stem is, it marks the lightest point of the tyre.
If your tyre fitter is putting it opposite he is also wrong.

On another note I often wondered about the weight of a pressure sensor that is fitted and putting an equal amount of weight on the other side. You might think this could cause an amount of rotational imbalance in itself. Surely the amount of weight all round should be near equal?.
Maybe I'm overthinking this
I have your understanding about the dot also - ie. I was always lead to believe the dot was the lightest point and should be aligned with the valve

You've lost me a little on your thinking for the balance weights . Surely the test is (at least this is what I did, hence it took a while) when the balance is correct, then if you gently set it spinning, day 10 times. Each time it should never stop at the same place. That's where I got mine to (before fitting the tyre). And surely, the counter balance has to be opposite the valve? I did say you lost me

You see videos where people hold the weights or valve area at about 9 o'clock the see if it swings a particular way. I don't like this because there is actually quite some drag from all the bearings in the train, so I estimate it's possible to get a false reading fairly often. So I opted for multiple spins, recording where the valve was at each stop...

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Its funny you should say that, i was under the understanding that cars have a white dot, and it should be opposite the valve , something to do with the join of the tyre bands/ beads cancelling out the mass of the sensor

But on a lot of cars they are nowhere near, which makes you think, do they just put the tyre on and balance as whole

My local bike tyre place cant balance gs rears as he dosent have a mandrill suitable for his balance machine, so he leaves on any current weights, and puts the dot opposite

haven't noticed any issues since it was done, and its due another set in about 4 weeks time
You've now got me wondering about that for position... I had the same understanding as gazza12adv...



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UPDATE:

Today I got out and did approx 120 miles with some motorway included. So great to be back out and mobile again!

So. Did all that effort change anything? The answer is a 100% yes .
I managed to sit at about 130kmh for a few stretches. The cycling vibration that was visible on the clocks and satnav has gone.

It's interesting how I had become programmed to expect the vibes to come in. I think I imagined they must be there at one point, but no. The give away is the clocks and satnav. They were clear indicators.

Feeling chuffed and relieved


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One more I forgot to mention - just a point of interest.

When I went to get the tyre taken off, while I waited I walked around the showroom. They had some KTMs in there, with cross spoked wheels.

The detail that really struck me was the thickness/diameter of the spokes. I'd say they are double the BMW spokes. Interested in the torque setting for those!

Has someone workout more support is needed?!

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