2018 R1200GS Rallye Spoke Wheel Truing

I bought this motorcycle, in spring of 2021, used, from a dealer in Vegas.  I flew out to pick it up, and on the way home I noticed a harmonic vibration from about 50 mph+? 6th gear, Frequency about 1Hz at 60-65 mph. I hadn't noticed it most of the trip, because I spent all my time on interstates fighting turbulence from the trucks and generally getting bounced around. But when I got on the smooth blacktop secondary highways in Alabama I definitely noticed it. By the time you get to 65 mph it's a clear wave pattern, the vibration peaks about every second (count to one one thousand), dies down, peaks again. As you go faster, the interval between peaks gets progressively shorter, and the vibration gets more intense. 

I would have bet my shorts that it was just tires/wheels out of balance, both of them, because the frequency just seems too low to be engine. Figured the wheels are different diameters so at some point in rotation they cancel each other out, at another point they add up, which explains the frequency.

I took it to the local shop and they checked the front wheel and said it's balanced, spokes are fine and it's true. They checked the rear wheel the next day and found it to be slightly out of balance. Not sure one tire could cause this kind of harmonic.  What ticked me off was them saying that it felt perfectly fine to them on the highway, and they had a couple guys take it for a ride.  So, much for their diagnostic abilities.  Paid them some money for their trouble and left.  I wasn't happy, mostly because I was working out with the selling dealer and the local one to fix that and a leaky fork seal.  But they couldn't confirm my seal was leaking, even though I had pictures that I had sent the dealer.  Long story...

I did find some info that said Tourance tires have been a problem for some, and it did have Tourance tires on it, fairly new one's.  And I wondered if maybe as the tire wore on the 2000 mile trip home, it just got worse.

I did some research on these cross spoked wheels and everything I read said don't mess with them.  If they are bent, you can't straighten them, and most dealers considered them throwaways if there was anything wrong.  Well, at $600 a piece, or whatever they cost... a ton... I figured I needed to try.  I did find a shop out in CO which was apparently the only one that actually straightened and worked on them... just in case I screwed them up.

So, dove into this thing. First, took off the front wheel and mounted it in a truing stand. Yeah, thought about taking the tire off, but why? I mean, if the wheel is bent, whether the tire is on or not, it's not going to effect my ability to straighten it with the spokes. I mean, it's rubber, right?

[​IMG]

A word about the truing stand. Bought it on Ebay, one of those China specials. It's solid enough, but barely had enough room for the tire. Not crazy about the bearings on it (don't spin as free as I'd like), or the rod (soft metal). Also, the front tire has a bushing on one side, but on the other it's just the rubber seal, so wasn't crazy about sticking those cones directly into the rubber seals, but it seemed to be OK, and I didn't have another bushing... And yeah, the kitchen counter is the best place to do this...

First thing. The little set/grub screws on each spoke. Yes, there is a screw in there... 40 of them...

[​IMG]

First issue is getting those loosened. Problem is that some of them were so caked with mud that I couldn't get a 2mm wrench in there. For those that I couldn't, I found that just loosening the main spoke nut took the load off the set screw. Some I could unscrew from there, others there was no way but to completely remove the spoke nut. At which point I would go in there with a smaller wrench or a small nail to work the mud out so the 2mm wrench would go in... Not sure BMW thought through this. Tedious to say the least. It would be nice to have plug on them to keep dirt and stuff from betting built up.  Obviously, if you're going to remove the spoke nut completely, you want to put it back, and tighten it to approximately where it was. I only had one spoke that turned and I had to hold it with a pair of vice grips when loosening the spoke nuts.

First shot at it, I just put the indicator on the side of the wheel and looked at how much wobble the wheel had. Somewhere between 2-3 mm max. Not bad. So, followed the usual spoke tightening approach. Found the most far out point, tightened the spokes to pull that section of the wheel away from that side, four to six spokes in that area. I pulled until I reached max torque (35 in-lbs). When the wheel still wouldn't pull over, I would loosen the opposite spokes. Anyway, after monkeying for hours, I wasn't getting anywhere. I could move the rim some, but it was always worse. The one spot that stuck out the farthest to my left, would not pull in to the right. So, my conclusion was that the rim was bent, and like it's been said, these BMW wheels are not the usual flexible spoke wheels. Clearly you can't really pull the wheel straight like you can on a dirt bike.

So, at that point, I just gradually loosened all the spokes, to the point where they were almost loose. Goal is to just get them all tight and torqued to spec., and see what the result is. With the spokes basically loose the wheel had that 2-3 mm side to side wobble. If I could keep it there, while tightening, that would be it.

Regarding the working pattern. I picked one spoke as #1 followed that down to the wheel, went across the wheel to the opposite spoke, went to that spoke nut, and marked that #2, on the other side of the wheel. Back to #1, on the same side, directly across from #1, I marked #3 (#1 and #3 are 180 degrees apart on the wheel, diameter), followed that down, across the wheel, #4. #5 was at 90 degrees to #1 and #3. #7 was 180 degrees from #5. And so on.  Basically tightening in a cross pattern. Here's some numbers on the wheel and in order from both sides of the wheel.

[​IMG]

This is all the numbers on each side, in order.

[​IMG]

Also, I started by finger tight on all spokes, following the pattern. Then turned the nuts one star point on the nut. Then went to about 12 in-lb, then 20 in-lb, then 25 in-lb, 30 in-lb, and followed the pattern until I got to 35 in-lb on all spokes. I guess you could take out your grub screws while you're tightening, but I had enough trouble hanging on to the little buggers, so I just left them in, making sure they were screwed in just deep enough to allow me to work the spoke nuts. I tightened them after all the spokes were at 35 in-lb. It seemed to work out.

What was the end result? I managed to keep the 2-3 mm max. side to side (same high spot as before). So, guess if I wanted that out, I'm was going to have to pay someone to straighten that wheel.

I reballanced the wheel and I was able to take off almost all the balancing weights on the wheel, some of which I put on to balance it before working on the spokes. Hmmmm... Could that mean that the wheel was out of round before, or shifted off center, and this gradual crosswise tightening process got it more round/centered? If it was off center, then weights would be needed to make up for the fact that there was too much wheel mass on one side. I can't think of any other explanation for it. On the heavy side I took off 1 oz of weights and a couple other 1/4 oz. I find it unlikely that I somehow managed to throw the wheel off center (if it was centered before) in such a way that it just happened to allowed me to eliminate weights. So, I'm hoping for a neutral or good outcome on the test ride tomorrow.

May 1 2021
Strike one. It's definitely no better. If anything, it's a bit worse. Nothing to lose at this point so I took another look at it. Since I can't change the side to side wobble, maybe I can get it closer to round.  There was definitely a spot where it was more than 2 mm out of round.... I can almost see the writing on the wall...

I went on ADV Rider and got the suggestion to look at this document:  Wheel_Truing_PDF.pdf And a guy said he started out 2.8 out axially and 1.3 radial. Wound up 0.3 axial and 0.2 radial. Dims in mm.

So, took a stab at the radial runout. Yes, both the tire and the wheel have their high spot at the same point, and the transition from high to low, as the wheel turns, is gradual (except for the spot where the wheel is bent, but I couldn't do anything about that) I guess that's a good thing as opposed to the tire in one spot and the wheel in another. Set my stand up again to attempt to fix that.

Bottom line... I did reduce the radial runout from about 2+ mm to about 1 or less (yes, i should get a dial indicator, but eyballing works pretty good). And riding the bike definitely shows an improvement. There is no more harmonic anywhere below 60 mph, no obvious cycle of vibration. At 65 vibration starts to creep in, by 70 the handlebars still shake noticeably, 80 it's worse, but all the way up to 120 mph it's no worse than it was at 80. But let's just say, as it is, I'm not going to be doing any high speed cruising. So, now I had a dilemma. Seeing as I do most of my riding on backroads, below 70 mph, should I try to take out the last of the radial runout, knowing that the side to side is still there and the rim will need straightening anyway, but that I might get some more improvement? Should I do that tire swap and see the effect? Or, do I take good enough, and ride it for the summer and just wear out that tire, change it then? Either way, when winter comes, the front wheels is going to Woody's. I'm thinking good enough for now, not not completely decided.

Sidebar 1: Normal Spoke Wheels. I called a motorcycle wheel specialist in Ohio, just to kind of confirm what's been said. First, these guys will guarantee that a wheel they fix will be between .003-.005 inches runout in both directions. But, no, they don't do the BMW wheels. They consider them throwaways, non repairable.

Sidebar 2: Yes, it's not impossible to maintain the spoked wheels. The one thing I've definitely learned is that, if my wheel wasn't permanently deformed, I would have a pretty good chance of maintaining these wheels, and keeping them tight and straight. Yes, it's intimidating, and you need lots of time, but it can be done.

Ok, so when it came to fixing the radial runout:
Basically, I renumbered the spokes to facilitate the work. I want to shift the wheel from the high side (rim far from hub) to the low side (rim close to hub), so have to loosen the spokes on the low side and tighten on the high. The spots are 180 degrees apart on the wheel, so that's good again. Starting at the high spot picked spoke #1at the wheel, #2 is right across from it, same side of wheel, #3 is next to #1 and #4 is next to #2. Then I start fanning out from that. #5 is next to #1, #6 is next to #2, #7 is next to #3, #8 is next to #4. Until all the spokes, on 180 degrees of the wheel, half half the wheel, are numbered #1 to #20. Then, go 180 degrees from #1 and duplicate the pattern on the other half of the wheel.

[​IMG]

First was the loosening. Started by loosening the low side in numbered order, 1/8 turn each spoke (you can start at 1/16 turn if you want to play it safer). Have to realize that technically, as you fan out from the high spot, and get to 90 degrees to either side, the amount you loosen should decrease. And I'm sure if I determine the thread pitch, on the spokes, and the angle of the spokes to the wheel, I could calculate exactly how much I could loosen each spoke to get exactly the movement I need at any given point (No, not going to do that.). But the spokes are rubber bands to an extent, and the wheels are really stiff, so I think there is some room for error. But, the fact is that as this process went on, some fuzzy logic comes into play, and the spokes at 90 degrees from the high spot do not get loosened as much as the ones directly at the high spot. The important thing is to do the same thing to spokes directly across from each other so as not to shift the rim in any way that you don't want.

I can definitely say that there are few things I have to thing about as hard as this process. Without numbering the spokes, and in the order you need to attend to them, it is so easy to get lost. And this did take me all day, like 6-8 hours. Talk about Zen and the Art of Motorcycle Maintenance.

Anyway, once the spokes were loosened 1/8 turn on the low half of the wheel, check the runouts, tightened them on the other half, again in numbered order, check the rounouts. Then check the runouts again, make sure you didn't screw anything up, make sure you're making progress, and repeat. Loosen one side, check tighten the other, check, etc... This is where it becomes clear that at some point the spokes at 90 degrees to the high and low need only 1/16 turn or nothing at all.

Other things come up, like when you ding the spokes you find one that has a high pitch and the one next to it on the same side is low pitch. In that case loosen the high one, tighten the low one, to keep the tension in that area about the same, but get the spokes more even in pitch so the load is better distributed between them. Also, when you're loosening and you find that almost all the tension in the spoke is removed. Check the tension in the spokes next to it and see if either is tight. Also check the spokes 180 degrees from that one, maybe tight.

Logical and methodical approach, and think about what you're doing and why, before you do it.

Then at some point you're happy with your results, the question is, how do you then torque them all down. First, when you're doing you're adjustments, use a torque wrench set at about 1/3 of the final torque. This acts as a stop, so that you think about why a given spoke may be tighter than others and how you can get them more even before proceeding.

But anyway, when you're ready to torque the spokes, you have to change your tightening pattern, back to the first pattern. Tighten in pairs, left and right side of wheel (to keep from pulling the rim from one side to the other), first at 180 degrees apart, then 90 degrees to that, and keep splitting the difference in the angle. Again, number them in tightening order before you start. Keep checking, gradually increase torque on each go around. Same fuzzy logic applies regarding spokes that are significantly looser or tighter than others. In the end, they should all ding at about the same pitch.

PROBLEM SOLVED!

Did my last test run she is smooooooth.... to at least 115 mph. No harmonic, no handlebar shakes, nada...

So, here's the cliff notes version. I trued the wheel again (another two days of work, making it four days of truing), with the tire off, using a different technique, and I changed the tire; pitched the Tourance for a Shinko 705.

So, here's the details.  This is my version of a bead breaker...
[​IMG]

My rim guards didn't work so well at first, so I had to heat them in an oven to get them to soften and open up wide enough to go on the GS rims. Clearly there's a better way. But I got the tire off.

Then I'm thinking, since I've got the tire off, how about another shot at the truing?

[​IMG]

So, here's what I did:
1. I took the same approach I described previously, but worked myself into a corner, I ended up with spokes which I needed to tighten, already too tight, and the one's I needed to loosen already too loose, and the wheel had two axial high spots 180 degrees apart. I'm sure if I think about it long enough I could understand why. But I wasn't going there... I suspect I was turning adjusters too quickly (1/8 turns).
2. Slept on it and next morning I loosened all the spokes, down to finger tight... again, do it gradually, small turns (1/16), using a cross pattern. And I went around again to make sure they were all just finger tight. What this shows you is just how much your wheel is actually out.
3. Took off one spoke nipple at a time, shot just a bit of JP1 off road thin chain lube into each one (no thick stuff), and worked the set screw (grub screw) all the way down and back up the nipple. That way the threads were lubricated and clean. Put it back on only finger tight again.
3. With all the nipples lubed, and the spokes just finger tight, just shy of loose, I checked the runout of the wheel. It was actually better than before. Seems like the process of stressing the wheel knocked something into place. Don't ask me how, but based on that OGSWTTv10 document, I just called it magic. At this point I put marks on all the nipples, so I could see exactly how far each one would tighten.
4. My job now was to get all the spokes tight and not tweak it in the process. I set my torque wrench to 20 in-lb and started the crosswise tightening process. Turning only 1/24th of a turn at a time. I did not deviate from my tightening pattern or my 1/24th of a turn at a time.
5. After the first round was done, I checked the runout and found that I had some radial, with high and low spots 180 degrees apart on the wheel. So, I renumbered the spokes on the rim 1-12 on one side and 1-12 on the opposite side, fanning out from the peaks. Loosen all of them on one side and tighten all of them on the other (180 degrees apart). This shifted the wheel on the hub. After a couple rounds, I was happy, and continued the overall tightening process. I only made one adjustment to minimize some axial runout in one spot.
6. When I got several spokes that were at or above 20 in-lb, I turned my wrench up to 25 in-lb. But I still continued to turn 1/24th of a turn at a time.
7. I checked spokes on the same side next to each other for sound. If they were not even, I evened them out, to share the load; loosened one, tightened the other. Then continued the tightening process.
8. When I got a few spokes the triggered at 25 in-lb I turned my wrench up to 30 in-lb. Same process.
9. Final step, turn the wrench to 35 in-lb. This time, if I hit 35 in-lb, it told me this was the last tightening cycle. If I hit 35, I still turned the nipple 1/24th. When that round was done, I was done. So, most of the spokes would be below 35 in-lb and a few may be slightly higher.
10. Again I checked paired spokes and balanced them if one was higher in pitch than the other.

IMG_6948.MOV

Basically, good enough. Aside from my camera movement, I'd say that's less than 1mm movement in both directions. And that spot I had before, which seemed bent, irreparably, was gone. There is little if any permanent damage to the wheel. Either way, it does also show that you don't need perfect to have a smooth ride.

Most spokes were at 1/2 turn of the nipple, past the marked zero point. In my previous adjustment cycles I was getting close to a full turn on some. Clearly too much. But, I really think those tightening processes did help to bring the wheel back in line.  But can't be sure.

[​IMG]

Then I debated putting the old tire back on, but given the difference between my first go around, vs my second and the fact that I had minimal affect on the vibration, I started to believe that my tire was at least 50% of the problem, so I skipped the old tire and just put the new one on. Well, I didn't... I had to do the walk of shame. Luckily I found a guy just a couple miles from me that was able to install the tire. He scratched my rim in the process, but at least the tire was on.

And the rest is history. I hit 65 without even thinking about it and without feeling any vibration. Got out to a straight piece of road... 115 mph before I decided I shouldn't kill any dogs, or myself running into a dog!

There you have it. Handlebar vibration, just shouldn't be there. If you have it, check your wheels and your tires. And a good Shinko is way better than a bad Metzeler!

I contacted Pirelli (They own Metzeler) about returning the tire to them.  I didn't even want a new tire, I just wanted to send them the Tourance so they could learn why the tire went bad, but it was a pain and I just gave up.

[​IMG]

It's January of 2021, been riding it all year and had no issues.  Recently I tightened the spokes on the real wheel because a few were not as high pitched as the others, and I wanted to get them more even.  No real issue.  Used what I learned on the front wheel and got it done in one day. 

And thanks again to everyone for their input.