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rear wheel failure

Raven said:
"This should be basic analysis that any reputable engineering firm could perform".

Or the insurance company could save thousands of dollars and just pay for the bike.
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Interesting note, my policy has a endorsement called Cae20 which states complete replacement , It was available because it was a new bike and I was the first to insure it. I read that as they buy a new bike upon loss. They are sure dragging their heals as its been almost a month........its not like I can ride anyway. lol I am leaning towards riding my V Strom first as I have an attachment of over 125,000km with it , the MG has sort of lost its appeal right now.☹️
 
Calvin,
I hope you continue to heal and get to a point where you are comfortable starting to ride again.

I am also a long-time rider of bicycles and motorcycles and have never seen a spoked wheel break like this. I had an XT500 Yamaha many years ago that had a few broken spokes in the back wheel when I bought it. I rode it off road for a while with the broken spokes because I could not find a local shop that was capable and willing to rebuild the wheel. I ended up selling it to a coworker before finding a shop to fix the wheel.

After looking at the rear wheel of my Centenario very carefully and seeing no signs of stress issues, I feel a little more comfortable riding it. In the photos posted above it looks like the heads of the spoke adjusters broke off--not the hub breaking around the spoke holes. The heads of the spoke adjusters are quite large and the damaged spokes are clearly missing the heads of the adjusters.
 
Calvin Cran said:
As the rider of this bike, I can say there is absolutely no rust or corrosion on these wheels. Bike is stored in dry climate garage and had only 9800km. Mitch posted this photo on Advrider, he is the person who drove 280km 1 way over night to pick me up and get me to an airport to go to a hospital. Nearest ambulance was 600km away. Bike is still at his house waiting for the Insurance company to make up their mind what to do. It is 1700km north of my city. Insurance wants to preserve the wheel for inspection.

Scott, question? if you were riding along at 80km/hr and your rear wheel started to wobble and then threw you to the ground would you not think something was amiss with the wheel? My RCMP report stated that I thought just before the accident that I had a rear flat. Upon picking up the bike they noted the rear still had 42PSI and was not flat. I just want to heal and be treated fairly with a pay out or new bike. I have not spoken to MG and realize that shit happens, I am happy to be alive as the pressure from the chest against my heart caused me to flat line for 3 to 5 seconds at a time literally a few dozen times. I was asked if I wanted to be resuscitated and they also put the pads on me ready to paddle me and jump start the heart.
Why was the spokes like this? We may never know.
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I am in your corner here. I just was trying to point out that there are many unknowns and that to immediately jump to “Piaggio is at fault” is not exactly a fair estimation at this point.

You stated that your tire had recently been replaced. Something could have been done wrong there.

I perform wheelwright work in my shop. It’s complicated and not something that should be trusted to some young buck in the back of a service department for obvious reasons evidenced here. The net result of doing an incorrect job can be catastrophic. I’m not saying that is what happened here but it is a possibility I cannot rule out at this time.

I don’t know if there is a published schedule for spoke maintenance and if this was adhered to.

Again, lots of unknowns. It hasn’t been fully analyzed yet.

I feel for you and I feel your pain and suffering as I have been on the shitty end of that stick myself.

Unfortunately, after discovering a second set of photos describing the exact same thing happening to another motorcycle in exactly the same fashion, I was beginning to formulate an opinion that you most definitely have some strong indicators of having discovered a potentially valid major flaw and life threatening safety issue that may warrant an immediate recall campaign.

However, I am confused. Are you saying that these are two different posts in two different forums of your same single motorcycle?

Are we talking 1 failed hub, or two?

I do not doubt you, I only want to remain objective in my analysis.

However, just like the snapping front fork tubes of BMW’s a few years back, this is a serious concern indeed and I believe it needs to be reported immediately to the NHTSB as a potential serious defect.

I cannot remember ever seeing such devastation of a spoked hub like these two sets of photos.

You are lucky to be alive and the fact that this has happened to you in the first place, that is extremely disconcerting to me.

My best friend and I, (we both own Stelvio NTX’s), we’re discussing this last night, and although I cannot offer conclusive information at this time, I am almost certain that when this plays out, that it will be discovered that these wheels that are failing, were sourced from China as opposed to the wheels on our Stelvios.

I cannot offer proof of any of this pure conjecture at this time but the thoughts are swirling in my mind. Definitely.

In my case, regarding spoke wheels, it’s academic and moot as I removed my spoke wheels for cast wheels years ago, but I still am extremely interested in how this plays out.

You are indeed a victim of circumstances in this. Again, I am on your side. I just don’t know what to make of this yet. That is all.

I am very glad you (both?) are still alive to tell the tale about this. I wish you a speedy and complete recovery and I hope you obtain total and complete satisfaction in the resolution of this.

Please know that I meant no offense to you whatsoever. Not one bit.

All my best to you. Truly.
 
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My first thoughts also were that the tire replacement had something to do with the mishap. When removing the old tire the nipples may have been damaged.
I'm not sure what the road surface was like but some Northern roads are done with "Texas Pea Gravel". Is there a chance that a large stone or stones kicked up from the front wheel could be in any way responsible?
 
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Calvin Cran said:
Do you touch the hub when replacing a tire?
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It depends.

Not normally but you wouldn’t believe the stuff I’ve seen people do when mounting and dismounting tires. I’ve witnessed every manner of lunacy and outright stupidity.

For example, I never change a tire on any spoke rim that I don’t put the wheel on my truing stand and tap every single spoke with a piece of steel, so I can listen for like tone among the spokes. Invariably I find 1 or more, out of tension with the others. Some, significantly so.

Most shops don’t employ old guys like me who know how to or take the time to do things like this.

I’m not making any accusation here, I’m just telling you that nowadays, it seems that just about anything goes as far as who dealerships employ as “mechanics”.

It’s a disgrace in the industry for sure.
 
JasonC said:
I apologize if I missed it, but how many miles are on your bike?

Jason
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Calvin Cran said:
No prior warning, I had just changed the oil and filter 200km before this in Fort Simpson and did not notice anything out of place but then again I was not looking at the wheel specifically. I think the insurance company wants to talk with Moto Guzzi, Ill let it play out with them. My expenses to get home were high due to the location. New tires were put on the rims at a shop in Calgary 1800km prior, you would think the tech would have seen a spoke out of position or broken when he did the tire change. I was loving the new Mitas E07/s Bike had 9800km at the time all gentle 68 year old rider km/s
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Raven said:
My first thoughts also were that the tire replacement had something to do with the mishap. When removing the old tire the nipples may have been damaged.
I'm not sure what the road surface was like but some Northern roads are done with "Texas Pea Gravel". Is there a chance that a large stone or stones kicked up from the front wheel could be in any way responsible?
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I don't see how flying rocks could be at all responsible. The heads of the spokes on the rear wheel are protected by the ABS tone ring and brake rotor on the left side and the final drive housing on the right side.

Since it is now clear that both sets of photos are from the Calvin's crash, I am concerned about the recent tire replacement being a contributing factor (I just don't understand how changing the tire could have overstressed the spokes).
 
GerryAZ said:
(I just don't understand how changing the tire could have overstressed the spokes)
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It is supposed to be an adventure bike and if changing a tire can ruin the rim? It was changed on a tire machine in a motorcycle shop, I guess any thing is possible. Does not really matter anymore as I am slowly healing and hope to be back riding and golfing in the future.
 
Just went out, popped my bike up on the center stand, and tapped each of the spokes on my rear wheel (21 E5); a virtual symphony of different tones was revealed. I have just under 4000 miles on mine currently. I feel flats toward the innermost portion of each spoke: assume these accept a spoke wrench? Anyone know what size, and if this is the correct way of adjusting the spokes on E5 tubeless wheels? Regrettably, I don’t have calipers handy. I also couldn’t find the procedure explained in the service manual…
 
Midnite said:
Just went out, popped my bike up on the center stand, and tapped each of the spokes on my rear wheel (21 E5); a virtual symphony of different tones was revealed. I have just under 4000 miles on mine currently. I feel flats toward the innermost portion of each spoke: assume these accept a spoke wrench? Anyone know what size, and if this is the correct way of adjusting the spokes on E5 tubeless wheels? Regrettably, I don’t have calipers handy. I also couldn’t find the procedure explained in the service manual…
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This type of work needs to be done on a truing stand with the tire off. And as Scott said earlier this isn't a job for a novice.
 
Tubeless wheels like Kineo and Alpina are typically factory laced in a jig. I imagine the stock TT wheels are the same. Same with the earlier Cal EV (German) BEHR wheels. They are not typically user serviceable.
All said, Scott has a valid point. If the tires have been changed from stock, it's a bit of a (terrible thought of a) crapshoot on whether or not they were mishandled.
I too will be watching/following this thread for new updates.
 
GerryAZ said:
…Since it is now clear that both sets of photos are from the Calvin's crash, I am concerned about the recent tire replacement being a contributing factor (I just don't understand how changing the tire could have overstressed the spokes).
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There is no reason to assume that the spokes were over stressed, at least in terms of static tension.

I am much more inclined to go the exact opposite way and believe that the wheel actually loosened up to the point of this failure.

I’ve seen failure of a single spoke or two from overtightening. The spoke broke but the remainder of the wheel stayed intact.

This gentleman’s wheel failed terribly all over the place which causes me to ponder the whole thing.

The strength of a wire wheel lies in the relative equal distribution of forces across the spoke pattern. When spokes loosen up from stretching, the wheel becomes significantly weakened in the process.

To me, I was taught that catastrophic wheel failure is much more likely from this loosening of spokes rather than tightening.

Besides, how would you account for this random tightening?

By his own admission, the OP denies modifying the spokes at all.

Spokes don’t gradually tighten. They do gradually loosen though.
 
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scottmastrocinque said:
There is no reason to assume that the spokes were over stressed, at least in terms of static tension.

I am much more inclined to go the exact opposite way and believe that the wheel actually loosened up to the point of this failure.

The strength of a wire wheel lies in the relative equal distribution of forces across the spoke pattern. When spokes loosen up from stretching, the wheel becomes significantly weakened in the process.

To me, catastrophic failure is much more likely from this loosening than tightening.

Besides, how would you account for this random tightening?
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Since the heads broke off the spoke ends at the hub, those spoke ends had loading (stress) beyond what they could handle. That stress could come from spokes being loose and not sharing the load with other spokes. I did not intend to imply that the spokes were overtightened, only that the heads broke off the spoke ends. I am sorry if my comments were out of line.
 
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