Going to the Dark Side

[Bustanut joker]

The Sky is falling! The Sky is falling!!!!!!!!!!!!!!!!!!!!!!!!!!!

:dribble:

 

[RaYzerman19]

For that rim to crack it would take pressure far greater than what someone might put into a tire. It would take someone on a tire machine that applied too much downward force when using a pneumatic hydraulic tire machine.

For this rim to form a crack, it was caused by 1) damaged by a tire mounting machine, 2) struck an extremely hard object on the road, 3) the rim was damaged during production and slipped by quality control.

When my CT was mounted, it took just under a 100psi to seat it. I run 32psi in my tire all of the time, there is no way under normal conditions the rim could crack due to the use of a CT being used. The width is within specs, as is the diameter. How the hell could the rim know what was mounted on it anyway. This entire discussion is ridiculous.

Agreed. And for those saying a CT side wall is stiffer, I would say a MC sidewall is stiffer when inflated to much higher pressures.... but this has nothing to do with the discussion anyway, IMHO. Rubber didn't cause that crack.

 

[doctorJ]

In my experience, to provide any naysayer with truth is just providing more information for misrepresentation (partial quote from George MacDonald).

Don't all the arguments get better? I'm running a Michelin Exalto, and it handles pretty well. It may not handle as good as a MT, but after a few thousand miles, I don't think about it. So if it works for me, how am I hurting or affecting anyone else? Why do you give a rip one way or the other. I may go back to a MT someday, but will you ever know it or will it make your day better in some way? I don't get the need for such hostility towards darksiders, but I may cave in and go back if my desire to please others wins out .

doctorj

 

[beemerdons]

For this rim to form a crack, it was caused by 1) damaged by a tire mounting machine, 2) struck an extremely hard object on the road, 3) the rim was damaged during production and slipped by quality control.

Rubber didn't cause that crack.

Actually Ray, if I had been wearing a rubber 45 years ago, we wouldn't have to be dealing with this crackpot SkooterG today! jes' sayin' and nuff' said!

 

[mjac]

This entire discussion is ridiculous.

Amen.

 

[Fred W]

So here is what I have been thinking about the recent rim crack:

First off, a Car Tire (CT) sidewall is significantly softer than a Moto Tire (MT). The radial CT's sidewall is designed to intentionally flex to allow the tread to remain more flat on the ground. regardless of the side load and wheel camber. That was the big difference between radial and bias ply tires, way back in the 60's.

A moto tire is intentionally made stiff in the sidewalls and becomes even stiffer when aired up. There is very little if any sidewall flex, which is intentional. So there should not be any added stress to the wheel's rim to cause a crack by installing a CT. Yeah, it might have been a dufus at the tire shop that stressed the wheel and cracked the rim.

Unless...

Suppose that you came upon an abrupt road surface imperfection. A CT with its softer sidewall (especially when run at lower pressure as is required for a light motorcycle load) may allow the road to come up and smack the rim when a normal MT would not. This is completely hypothetical at this point, based only on what was previously reported (cracked rim, dings on the wheel rim). Seems like a plausible explanation of what might have happened.

 

[palerider]

Suppose that you came upon an abrupt road surface imperfection. A CT with its softer sidewall (especially when run at lower pressure as is required for a light motorcycle load) may allow the road to come up and smack the rim when a normal MT would not. This is completely hypothetical at this point, based only on what was previously reported (cracked rim, dings on the wheel rim). Seems like a plausible explanation of what might have happened.

I suppose that's theoretically possible, but that would have to be one hell of an "abrupt road surface imperfection," and I think the OP would have remembered it. Also, he would have hit it with the front wheel first, and I think he'd still be seeing his dentist for oral surgery.

Much more likely to have been done in the shop, but if not the shop then the OP may have done what I did once--hit a single, sharp rock so hard it ruptured the tire and deformed (but did not crack) the rim. Although I'm pretty sure he'd remember that too.

 

[Warchild]

Much more likely to have been done in the shop

Well.... there does seem to be some evidence that the shop may not have introduced the crack on this wheel when mounting the CT.

Because if that was the case... if they used too much force and split the wheel..... then how is it that the car tire held air just fine and ran 40,000 miles before this mishap? :huh:

Unless, of course, one simply wants to *believe* that the mounting job was the culprit, and that the tire machine did induce the crack, but it just didn't manifest itself until 40,000 miles down the road. Or that the wheel was a manufacturing "one-off" that slipped by the QA process.... then again, how did this one-off manufacturing "defect" wheel manage to run the car tire 40,000 miles before failure? (plus whatever mileage Doug had on the wheel with a proper tire on it).

:dntknw:

 

[Spud]

You guys are making this too complicated. It's clear the only logical explanation is metal-eating nanites from an alien race, like in the movie "the day the earth stood still."

 

[beemerdons]

You guys are making this too complicated. It's clear the only logical explanation is metal-eating nanites from an alien race, like in the movie "the day the earth stood still."

+1, Gunny; finally the Voice of Reason, thank you Spud!

 

[palerider]

Much more likely to have been done in the shop

Well.... there does seem to be some evidence that the shop may not have introduced the crack on this wheel when mounting the CT.

Because if that was the case... if they used too much force and split the wheel..... then how is it that the car tire held air just fine and ran 40,000 miles before this mishap? :huh:

Unless, of course, one simply wants to *believe* that the mounting job was the culprit, and that the tire machine did induce the crack, but it just didn't manifest itself until 40,000 miles down the road. Or that the wheel was a manufacturing "one-off" that slipped by the QA process.... then again, how did this one-off manufacturing "defect" wheel manage to run the car tire 40,000 miles before failure? (plus whatever mileage Doug had on the wheel with a proper tire on it).

:dntknw:

Metal can fatigue and cracks can develop/worsen over time, then just open up. Just ask anyone in an aluminum-skinned jetliner when the roof blows off. Just before he gets sucked out of the airplane, ask him if he saw a crack. The wheel in question could have been dinged in the shop or it could have been a factory defect and not shown up for a looooong time. I'm not arguing for any particular theory, just listing what in my mind seems a more likely scenario than hitting a bump so hard that it would crack your rear wheel and ding it in several places without hurting the rear tire or your front wheel and tire--which would certainly hit first--and you not remembering it.

Of a bunch of far-fetched possibilitis, in my mind that last one is the farthest-fetched.

I've hit a lot of bumps with a lot of car and bike tires, sometimes underinflated, and never damaged a rear tire or cracked a rear rim.

 

[HaulinAshe]

I'd bet my left nut that's a vibration-enhanced crack. I've worked with different aluminum and titanium alloys for years in applications where various frequency vibrations induce metal fatigue. Cracking aluminum with pressure alone doesn't look like that. Vibration combined with stress/pressure does.

IMO there's no doubt something is going on that the wheel was not designed to withstand. Basic troubleshooting dictates to look at what has most recently changed. What is the one thing that's significantly different about this situation than the thousands of others which have never experienced a similar failure?

If a similar failure was found by an FAA inspector on a commercial aircraft, the entire fleet would be grounded for x-ray inspection of the wheels. That's a BAD crack, no matter how fast you ride.

 

[doug5551]

Hey Guys,

Thanks for all the attention. When Mr. Ocfjr started this thread, it was in the interest of complete and full disclosure, and a commitment to tell the community about our experiences, good, bad and indifferent w/r/t running a CT on a motorcycle. I posted the absolute best photographs I had to illustrate what happened to me and to share it with all.

Some additional facts:

1. The tire was initially mounted using a "Coats" machine by a guy in San Diego who was extremely experienced with mounting CTs on motorcycle rims, because all of the Goldwing Darksiders use his services. He mounted and balanced it for $20 in about 5 minutes. It was easy for him and there was nothing difficult or remarkable about his mounting job. I was there when he did it, and as Warchild pointed out, it worked just fine for 40K consecutive miles.

2. As I said I would do, I called Dr. John's MFS(Motorcycle Frame Straightening) for additional clarification. I was calling it a "split" rim, but according to them the correct term, which I believe was introduced by Ignacio, is a "Cracked" rim. They said that they Trued and Rewelded it during the repair. They said they used a "Dial Indicator" which is accurate to .001 (thousandth)tolerances. They said there was "absolutely no doubt" that the cracked rim was caused by hitting something, and said that if you hit it just right, it would not take a severe hit to cause it. As I said, there was evidence of other dents on the rim during their repair.

3. The day before I had ridden 900 miles during my "Iron Butt 5000, Revisited" simulated rally. There were no dirt roads and nothing notable hit on that ride. I then parked it outside my place in Big Bear. Next morning took off for LA without any inspection, because all seemed normal, heading down a 50 mile mountain road, in rainy/snowy weather. It is a route I have taken many hundreds of times. Nothing notable happened till about 25 miles into the ride when it seemed as though I was riding on ice, so I slowed and took it easy. Symptoms got worse over about 15 miles till I pulled over, and then rode an additional mile on a completely empty tire.

4. I believe the rim has 100K miles on it. I got the bike with 52K miles on it, and have no indication that the previous owner had replaced it or experienced anything unusual.

5. Rim will be available for all to see in Seattle in a little less than 2 weeks...

 

[Catfish]

Just jumped back on to read the latest (and not ALL of the latest).

I just have one question for Doug, did you secure another wheel for the big dance?

 

[doctorJ]

For this rim to form a crack, it was caused by 1) damaged by a tire mounting machine, 2) struck an extremely hard object on the road, 3) the rim was damaged during production and slipped by quality control.

Rubber didn't cause that crack.

Actually Ray, if I had been wearing a rubber 45 years ago, we wouldn't have to be dealing with this crackpot SkooterG today! jes' sayin' and nuff' said!

Well let's see, 45 years ago would make you what maybe 7 or 8 years old??? You wouldn't be thinking about or know about rubbers then :yahoo: . You were just poking fun at some girl.

doctorj

 

[user 213]

Some interesting speculation about Doug's cracked wheel. As HaulinAshe suggests, this appears like a stress fracture. However, fracture rates in alloy metals follow a infinite curve. Simply put, if you're bending or applying harmonics to aluminum, it will break. It's simply a matter of when. Steel will flex, aluminum will not. Stress fractures can start at defects in a casting or forging, as well as a deformation. That the wheel took a hit is with out question. When? That's simply unknown. It may have taken 60k miles for the weakness created by the deformation to turn into a crack. And an additional unknown number of miles before that crack became bad enough to leak air. I can guarantee that that crack did not form over-night or instantly after a one time hit. As Doug says, there was no noticable big hit prior to the loss of pressure.

So, when was the last time any of you really looked at your rims? :blink: Pardon me while I go inspect mine. I suggest the rest of you do the same. **** happens. What tire you're using has little to do with said ****. Or this crack.

And remember, just because SkooterG hasn't seen it, doesn't make it unusual. Papa Chuy told me Skooter hasn't ever seen is **** either, but still believes it's down there.... somewhere. I always wondered why Skooty's folks called him 'Sally'.

edit: And about those "low" pressures. That tire, on a car rim, would be running those same "low" pressures. On the moto rim, there is a significantly larger amount of rubber bead hanging over the rim. Oddly, just like the newer rim protector beads built into low profile car tires. Things that make you go Hmmm, indeed.

 

[RaYzerman19]

4. I believe the rim has 100K miles on it. I got the bike with 52K miles on it, and have no indication that the previous owner had replaced it or experienced anything unusual.

The history seems vague. Is it possible this rim was bent and 'repaired' at one time, and a crack has now appeared after many more miles?

 

[Fred W]

So, when was the last time any of you really looked at your rims? :blink: Pardon me while I go inspect mine. I suggest the rest of you do the same. **** happens.

Ummm, that would be every time I change a tire, on each wheel I fully clean the rim bead. I'm sure that I would notice a crack forming during that. Just one more advantage to mounting your own tires at home.

What tire you're using has little to do with said ****. Or this crack.

And what data is that conclusion based on? While having only one data point (and a vague one at that) one can not conclude whether the crack was due to the CT or not, but the coincidence does give reason to suspect it (hypothesize). We would need several more CT shod rims to crack in order to show any statistical significance. Or just one MT shod rim to crack to disprove it.

 

[Warchild]

So, when was the last time any of you really looked at your rims? :blink: Pardon me while I go inspect mine. I suggest the rest of you do the same. **** happens.

Ummm, that would be every time I change a tire, on each wheel I fully clean the rim bead. I'm sure that I would notice a crack forming during that. Just one more advantage to mounting your own tires at home.

Exactly so.... whenever I change my tires, my rims get a careful going over while I clean the rim bead as well, both the FJR and Hayabusa. Again, in all the years I've been working on these machines, I have never, ever seen a cracked rim like this one. Ever.

What tire you're using has little to do with said ****. Or this crack.

And what data is that conclusion based on? While having only one data point (and a vague one at that) one can not conclude whether the crack was due to the CT or not, but the coincidence does give reason to suspect it (hypothesize). We would need several more CT shod rims to crack in order to show any statistical significance. Or just one MT shod rim to crack to disprove it.

Exactly, Fred.

And yet the fact is that we have NEVER seen this situation on thousands of FJR rims running millions of motorcycle-tire miles combined... by comparison, there only several dozen darksiders who have no where near this accumulated mileage, yet this cracked rim situation occurred anyway.

I suppose one could just blithely ignore this glaring coincidence. :huh:

In any event, I know Doug won't have this kind of tire mis-application at the Start Line in Seattle in two weeks. He knows better now. With a proper motorcycle tire mounted up, he has one less safety issue to stress over. Not the case for other Darksiders running the IBR. Like they need more stress. How many times will that image of the cracked rim flash through their minds.... on Day 7.... on Day 8.... on Day 9.... Day 10....

 

[user 213]

And what data is that conclusion based on?

Exactly my point Fred. The lack of sufficient data here suggests that anything we project is merely a WAG. What is known is that the rim took a hard hit. The evidence and informed observation of the shop that repaired the wheel, (whom has seen many similar cracks), is pretty solid on that issue. When the hit occurred is unknown. How long the crack has been there is unknown. I think you understand that a fatigue or stress crack can be almost invisible for a long time before it becomes large enough to produce a failure.

While having only one data point (and a vague one at that) one can not conclude whether the crack was due to the CT or not, but the coincidence does give reason to suspect it (hypothesize). We would need several more CT shod rims to crack in order to show any statistical significance. Or just one MT shod rim to crack to disprove it.

Just because we haven't seen a MT shod rim crack, doesn't mean it hasn't happened. I don't know of a Wing wheel with a CT that's cracked, but I haven't even looked. I've seen at least a dozen aluminum car wheels with this type of crack. All associated with a big hit, (usually an Oregon pot hole) and low profile tires. Usually this is on vehicles running +3" tire/wheel combos. (3" larger wheel, same size OD on the tire to maintain reasonable speedo accuracy, so greatly reduced sidewall profile).

From these observations, I can tell you with certainty that wheels will crack if a hard hit occurs. I can not tell you how long it takes after the hit for the crack to develop, nor can I tell you if the CT on the moto rim makes the wheel more or less susceptible to damage during a hard impact. I know I've taken some pretty hard hits in the 150k miles I've put on my particular set of FJR wheels and have no cracks, at least that I can visibly see. I'm not going to go dye penetrant test or xray my wheel any time soon either.

My instinct is to suggest that simply by the nature of a larger contact patch & thicker rim beads, a hard hit would be spread out more and be less likely to do damage to a moto wheel with the CT in place. I haven't measured wheel stresses, but don't believe there is a significantly different amount of stress on the wheel running a CT over a MT.

Right now, this is an aberration. Doug555 has done an excellent job of documenting the situation, and pointing out a much more important issue than the crack. That if you run a CT w/o pressure, you can expect some internal damage that will not be visible from the outside. This is the part that Darksiders should be taking away from this incident.