| Author | Message | ||
     Treefrog |
I'm posting this on the Quick Board for more exposure. This wasn't me and I do not personally know the rider, but he was on a Uly. He was ATGATT, but still fractured his neck. Other than that is in pretty good shape. The information I have is that he was running some twisties and was going into a left hander. The bike stood up and wobbled then went into a tank slapper. Up until this time, the rider had never touched the brakes. Once into the tank slapper he got on the brakes, then went over the bars and off the road. The rider with him states pieces of the wheel and a spoke were found on the pavement before he ever went off the road. This is a new one for me. Anyone seen a failure like this before? Please, discuss.   | ||
| Thumper74 |
Nope! I also wonder the sequence of events. Without seeing more of the wreck, it's it's difficult to say. My gut says they went in too hot, the bike straightened up and they hit something. | ||
| Boogiman1981 |
yeah that's pretty wild hope he heals up ok. as for the wheel failure. no i can't say i have ever seen anything quite like that under road conditions. i would want to see a metallurgical report on the wheel and a complete reconstruction of the wreck. | ||
| Bosh |
Scary stuff. From the description of the event, it sounds like it wen't down like Thumper's theory. You can't really tell what happened from the pics. I think if it was a sudden catastrophic failure you wouldn't have the standing up tank slapping thing going on. Also going by the broken rim.. looks like he slammed into something after he went off the road to me. Anyways, I hope that's the way it went down.. eyikes.. | ||
| Treefrog |
I don't know if he hit anything or not once he left the road, but apparently the wheel failed while he was on the highway. One thing I just noticed though, what is that? I don't know of anything on a Uly that looks like that. Maybe he hit it in the road and it kicked it up into the spokes? Just speculating here.  | ||
| Sifo |
That is an odd looking piece. I have seen sticks thrown into mountain bike spokes when they are hit on their end. That could happen with what appears to be a piece of steel. It seems equally odd that the piece would manage to stay with the wheel through the whole wreck though. Hope the guy heals up OK. NASTY! | ||
| Stirz007 |
If he somehow picked up something like steel (hunk of angle iron?), there would probably be some marks on the back of the forks where that thing got taken for a ferris wheel ride. Some of us are racing these wheels, and I'd rather not think about catastrophic fatigue failure. | ||
| Luftkoph |
That mystery piece may just be the plastic fork guard. | ||
| Boogiman1981 |
Where is the rest of the wheel. Need pics of the road surface as well. More questions than answers. | ||
| Mr_grumpy |
Spokes all appear to be bent back, indicating that the rim was trying to go faster than the hub. I'd be looking at wheel bearing failure as a likely cause. Bearing cage collapses, wheel starts wobbling, disc drags in caliper, causing stand up then tank slapper, bearing seizes & rim keeps going against a stopped hub, wheel fails & rider goes over the top . | ||
| Pwnzor |
Wheel bearing failure gets my vote. | ||
| Hughlysses |
It seems like the wheel bearing theory will be pretty easy to confirm- if the remains of the wheel hub won't turn, that must be the problem. | ||
| Reepicheep |
I'm not buying the wheel bearing thing. I could see a bad failure making you lock up and low side, but not just exploding a wheel like that. The rear "spokes" seem straight, the front seem "exloded" which seems to me to suggest a frontal impact scenario. Is that a scorpion trail front tire? And is it the camera flash, or is that a non Uly front wheel (i.e. XB9R) mixed with a Uly rear wheel? | ||
| Mr_grumpy |
The thing is Reep that those wheels aren't designed to take a torsional load through the hub, braking force goes direct from rim to fork leg with the ztl system. So if the hub locks up, 500lbs odd of bike & rider will be trying to rip the centre out. That's what led me to think wheel bearing. Added to that, we have no idea of this bikes history, for all we know the owner (or a previous owner) may be a wheelie & stoppie addict. Who can say what previous abuse the wheel's had, it'll probably be a combination of factors leading to a catastrophic failure. | ||
| Natexlh1000 |
That angle iron thing may be a light bar. A locked up bearing wouldn't be able to apply that much torque, would it? Usually, a killed bearing would just spin on the axle. I'm voting a "thing" was introduced to the wheel from the street. A stick or that mystery angle iron. Perhaps something took out one pair of spokes and set the wheel out of round. Brake force+missing structure=more missing structure? I hope we find out what the actual cause is and of course I hope the rider recovers quickly! | ||
| Danger_dave |
No known history of wheel bearing failures......wait..... | ||
| No_rice |
dded to that, we have no idea of this bikes history, for all we know the owner (or a previous owner) may be a wheelie & stoppie addict. i do doubt that would cause a problem with the wheel integrity though. mine have been jumped, stoppied and wheelied in excess. on the 1125's the front will come up in first and the wheel will be at a dead stop when it sets down doing 160's. if it was going to snap id think that would do it! | ||
| Hughlysses |
I tend to agree a wheel bearing wouldn't have been likely to break the spokes like that. A solid-seized wheel bearing usually spins inside the wheel, which ruins the bearing bore, but it probably wouldn't instantly stop the wheel causing all the spokes to shear off. | ||
| Kenm123t |
Check out the rotor its bent from being forced out of the caliper. I think he hit something pot hole or a highway divider curb. It looks like the brake rotor was pushed back as the wheel collapsed. | ||
| Glitch |
Looks like he hit something Maybe not the reason he wrecked, but I'd bet during the accident he hit something | ||
| Sifo |
Check out the rotor its bent from being forced out of the caliper. I think he hit something pot hole or a highway divider curb. It looks like the brake rotor was pushed back as the wheel collapsed. The rotor could also be bent simply because it was bolted to a wheel that fractured into multiple pieces. I tend to agree that he most likely hit something and caused damage before the crash. Then again, there could have been a casting defect in the wheel that caused the failure. Fatigue is also a possibility that needs to be looked into, but I have real doubts about that given the number of XBs on the road and we don't hear about this happening. Without close examination of all the pieces by someone familiar with failure analysis we are just speculating. Not that there's anything wrong with that. Just as a bit of further speculation, the design of the XB spokes would be a very weak design against any foreign objects being introduced into a spinning wheel. It would be nice to hear from the rider for a first hand account of the incident. Treefrog, where did you come by these photos? I'm not clear if you saw this on a group ride, found it on the internet or what. Just wondering if there's any other info available. | ||
| Reepicheep |
And why on earth is a silver (XB9) wheel on a Uly. I know the rear XB12X wheel is stronger, not sure about the front. I'm sticking with the "no way can a siezed bearing apply enough force to rip that wheel apart" theory, and adding "even if it did sieze enough the bike would just stoppie without breaking the rim". Although I might give you something along the lines of "massive bearing failure causes wheel to wedge on caliper or fork". Or "caliper comes off and gets ingested into wheel". | ||
| Ratbuell |
The weak link in the bearing theory, is traction. NO WAY a tire has enough traction to bend freakin' spokes. Period. The tire would slide on pavement LONG before bending spokes. My vote goes to impact, or FOD. I saw Geoff May get shoved off-track at NJMP last weekend, at the end of the front straight (probably what...well over 120? 150?). They brought his bike back to the pits in wheelbarrows. The ZTL caliper was attached to the bottom section of the fork; the rest of the fork was in another wheelbarrow. He gave 3/4 of the front fender to a young fan, autographed, as a souvenir. The wheel was fine. Bent from impact, but not broken, and definitely not in a rotational pattern like this one. Grumpy - your theory is wrong. The ONLY path for braking force from tire, to bike, is through the hub. Period. That is the only connection at all between the road surface and the bike - the axle. The braking advance is ZTL isn't that the spokes are removed from the stopping equation altogether - its that the braking force goes directly to the rim from the brake, without having to travel through the spoke (i.e. hub-mounted disc). But the fact remains that the motorcycle is only bolted to the wheel at one place - the axle. The torsional load of actually stopping the motorcycle is always there; ZTL removes the layer of *braking* torsion from the spokes - *braking* doesn't have to travel through a spoke to get to a tire to slow the WHEEL, but the braking force of the wheel slowing the BIKE still goes through the spokes and hubs and axles. The only connection of brakes to fork leg, is where the caliper is mounted. Actually slowing the motorcycle is done by the rotating wheel, combined with traction of tire-to-road. All the caliper does is "drag down" the rotational speed of the tire...which is only attached to the motorcycle at the hub/axle. It's a Dunlop D616 tire. | ||
| Psykick_machanik |
Im voting on "catastrophic wheel (spoke/hub) failure". If that is an XB9 wheel its sure not built for off road abuse like a Uly can dish out. Im thinking the hub or spokes took some off road damage that went unseen and then progressed to the point of catastrophic failure. Bearing failure- cannot produce enough torque to fracture the spokes. FOD- the odds are wayyyyyyyyyy to high.. (watch the Myth Busters about this very subject) Impact- If he hit something hard enough to grenade the wheel the forks would have been pushed back into the frame. Previous damage, to metal fatigue gets my vote. whatever the cause i sure hope he makes a full, speedy recovery. | ||
| Treefrog |
Treefrog, where did you come by these photos? I'm not clear if you saw this on a group ride, found it on the internet or what. Just wondering if there's any other info available. The other rider (the witness) and I are on a local internet forum. He was following the Uly rider when he went down and took these pics with his cell phone. He states there were bits of rim flange and a spoke on the pavement before the bike ever left the pavement. From what I am getting from him, the rim started coming apart on the road and is what caused the accident. I hope the rider can shed a little light on things once he is able. I would like to look at the bike, but it is too far away for me to see it. After looking at the pics, I tend to believe a foreign object somehow got picked up into the spokes. I will ask if there was anything in front of the Uly that may have kicked something up. I've got one more pic that was sent to me. I believe this pic was taken the morning after the accident after the bike had been towed.  | ||
| Mr_grumpy |
Rat, yes the force path between contact patch & vehicle goes through the hub, but the braking load on a ztl rim doesn't, as the disc is rim mounted. This allows a much lighter construction to the wheel as the spokes don't have to carry a torsional load, only compression/extension loads. Which is my point, on any bike with a hub mounted disc I'd agree entirely, as ALL the forces have to travel from rim to hub then up the fork. This wheel isn't like that though, the twisting element between hub & rim is totally absent hence "zero torsional load" so an introduced torsional load, such as a bearing lock up may be enough to cause collapse. We're all speculating here with very little information. | ||
| Hughlysses |
If that is an XB9 wheel its sure not built for off road abuse like a Uly can dish out. Im thinking the hub or spokes took some off road damage that went unseen and then progressed to the point of catastrophic failure. According to what's been posted here more than once, the only structural difference between an XB12X wheel and any other XB wheel is in the machining of the rim. The XB12X wheel is machined so that a little more "meat" is left in the rim so it is more resistant to bending from impacts. There is no difference in the spokes or hub. If the spokes failed, it wasn't because a non-XB12X rim was used (assuming that's not an XB12X rim). | ||
| Paint_shaker |
Many people have raced on these type wheels without incident (much higher braking forces and way more heat build up). However, catastrophic failure is always a possiblility. As as a foreign object getting stuck in the spokes. The marks on the pavement would also tell alot. | ||
| Ratbuell |
I hold that a locked bearing would slide the tire against the pavement, not twist/break spokes. I run those tires on my Ulysses and I love them. I've slid the front tire with the brake lever if I ham-fist the lever. Never come close to twisting spokes or bending a rotor. As noted above, the Uly rim has a strengthening "strip" in the rim itself to protect against "off-pavement" bumps and bruises, to keep the rim round(true). Spokes, hubs, etc., are unchanged from other XB's and 1125's. | ||
| Sifo |
I hold that a locked bearing would slide the tire against the pavement, not twist/break spokes. I run those tires on my Ulysses and I love them. I've slid the front tire with the brake lever if I ham-fist the lever. Never come close to twisting spokes or bending a rotor. I don't know if a seized bearing would collapse the wheel or not, but I do know that hitting the brakes with the ZTL braking system has completely different loads than braking at the hub, as a seized bearing would do. That wheel isn't designed for that kind of torsional stress. That's why it's called a Zero Torsional Load braking system. Personally, based on my experience with ball bearing race failures, I don't think the bearing would seize in the first place. Normally the balls get destroyed and will eject from the race leaving just a very loose set of inner and outer races that have way too much clearance to ever seize up. I do wonder about what looks to be heat marks on the rotor in that last picture. I'm not sure how that would have anything to do with this failure, other than the fact that it looks VERY abused. |
