Another fragile GS

[AlsoRan]

When you're at speed in random terrain like this, anything can happen, especially if you're not a very good dirt rider and you don't make the proper response after the initial upset. I doubt the cause was mechanical failure. And hard crashes break stuff. Nothing unusual there, Yamaha, Honda, BMW, whatever.

- Mark

Exactly. It looked like he just lost it in the sand and when the bike cartwheeled is likely when the swingarm broke. The rider looked tentative for the speed they were going.

 

[markjenn]

Exactly. It looked like he just lost it in the sand and when the bike cartwheeled is likely when the swingarm broke. The rider looked tentative for the speed they were going.

I've seen accidents like this on video numerous times and even witnessed a few myself. The idea that you can't lose control in this manner at these speeds in unpredictable terrain like this is hogwash.... it happens all the time. Without examining the bike, mechanical failure can't be ruled out, but it is MUCH less likely than simply the rider losing control. The weakest link is typically the nut behind the handlebar.

It reminds me of the pictures of a broken Gixxer frame circulating a few years back with armchair mechanics declaring with certainty that the frame failed and was the cause of the accident. Only later did we learn that the rider lost control and hit a wall.

- Mark

 

[EricV]

Riiight. How many failed driveshafts and broken u-joints on BMWs have you actually seen in person Markjenn?

Less than I have it would seem. Put the Koolaid down and step away from the keyboard.

 

[autoteach]

I did a shaft this last summer on an 1150GSA because it was basically unrideable because of the bearings locking up in the joints. When they blow apart, and they do, it isn't any good. The old air heads had steel swingarms and could take the hit. I doubt that an aluminum one can.

 

[markjenn]

Riiight. How many failed driveshafts and broken u-joints on BMWs have you actually seen in person Markjenn?

None. That's my point. Yes, they happen. But in the overall scheme of things, they are still rare events. Are they the likely cause of a loss-of-control accident when someone is bombing along over open terrain at 70 mph? Absolutely not.

- Mark

 

[EricV]

None. That's my point. Yes, they happen. But in the overall scheme of things, they are still rare events. Are they the likely cause of a loss-of-control accident when someone is bombing along over open terrain at 70 mph? Absolutely not.

- Mark

And that's my point, you haven't seen much of this stuff in person. I have. Not massive numbers, but specific to this issue. I've also seen enough crashes an crashed bikes to make the comment that I've never once seen a broken swing arm from a crash, with the exception of a multi-vehicle street impact at high speeds.

I have seen multiple broken BMW swingarms that resulted from the known weakness of the poor u-joint quality and drive shaft breaking. If you understood the design, you'd understand how easy it is to break the swingarm with a broken u-joint or shaft flailing about inside it.

It's a known failure. The rider in the vid was bombing along just fine for quite some time, he didn't "just crash". There was no significant change in terrain. When the u-joint or shaft starts to go, there is a major vibration in the bike and the common reaction is to back off the throttle and apply the brakes, which he clearly did, but if the rear wheel locks at that point, it can be bad. I don't know if the rear wheel locked on this bike or not, but a little yard sale crash of the bike just doesn't apply forces anywhere that will break the swing arm like that, and it wouldn't have a broken shaft either.

Yes, none of us were there. To some degree we are all making guesses. But, as I said before, I've seen this exact type of damage multiple times before, in person, up close and know what caused it.

 

[AlsoRan]

It's a known failure. The rider in the vid was bombing along just fine for quite some time, he didn't "just crash". There was no significant change in terrain.

Definitely not significant change of terrain if on a properly prepped KX500 or KTM, but there is significant change for a fully loaded GSA. Add an untrained rider that could not read this properly and one could just crash. Watch the camera bike and you can see the rocks that appear in the area as he stops, those are a signal that there is change happening and at 50, 60 or 90 mph it comes up quickly. In the desert like that where the wind blows softer sand likes to build up next to rocks and even burry the big ones that do not surface, it can be gradual (and may go undetected if not careful) or it could be a sudden drop but in either case change is occurring. This can be a good thing or bad but always is a "signal" that must be read first as a threat, then if so what is the duration of the threat. This decision needs to take place in a flash. Then there is a host of next decisions that go with it.

It appeared that the GSA rider was signaled by the camera rider to lead, if even a good rider is not accustomed to leading a group at those speeds in the desert, then anxiety or pressure can divide attention away from reading the terrain and in an instant there could be trouble. As the bike entered the sloping soft sand it began move around then go into a full blown swap and highside. Could not see it because of the dust, but I would vote that that the tumbling 500+ pound bike at that speed could break a hollow aluminum cast swing arm. I've bent a few but it was only a 240 pound bike tumbling at 50+ mph. Seems if it broke before it sure would have created havoc on the drive shaft and locked it up and likely a very different looking crash.

 

[dcstrom]

To me, the brake lights going on are a big clue. Any rider that has some experience (These guys seem fairly experienced?) in riding terrain like that would have had the bike "loose" on numerous occasions. They would know not to shut the throttle when that happens, and in fact sometimes you need to accelerate. Most of the time you can just let it be loose and it will straighten up of its own accord when you get out of the soft patch. Whatever... the last thing you want to do is get on the brakes. Unless... you heard or felt something go "bang!" from the rear, and have the bike getting loose immediately afterward. In that case, you know you're probably going down so you want it to happen at as slow a speed as possible. THAT would explain why he got on the brakes. Make sense?

 

[markjenn]

Unless... you heard or felt something go "bang!" from the rear, and have the bike getting loose immediately afterward. In that case, you know you're probably going down so you want it to happen at as slow a speed as possible. THAT would explain why he got on the brakes. Make sense?

No. Maybe he got on the brakes because he began to lose control due to some soft sand, rocks, upcoming hazard, spooked by another rider, whatever. This is BY FAR the most likely scenario, riders do this all the time. We know nothing about this guy's experience. The natural reaction of most riders when they're surprised by something is to brake.

- Mark

 

[EricV]

No. Maybe he got on the brakes because he began to lose control due to some soft sand, rocks, upcoming hazard, spooked by another rider, whatever. This is BY FAR the most likely scenario, riders do this all the time. We know nothing about this guy's experience. The natural reaction of most riders when they're surprised by something is to brake.

- Mark

The problem I have with that Mark is the terrain. At those speeds, in that terrain, you're either a complete idiot to go that fast, (which I doubt here), or you know that loose means get on the gas to float the front end. I'm hardly the king of off road, but even I know that. Backing off sharply, (closing the throttle), could certainly get you into trouble, but braking means, (to me), that something happened and he's trying to bleed off speed before it goes catastrophic. Having been riding with someone when they lost the drive shaft u-joint, that's pretty much exactly what they did. Back end got loose, serious vibration and clunking noises/feel and they backed off and started braking to dump speed. They were on pavement, and almost got to a stop before the wheel locked. This guy is in a much more variable conditions. I just don't see that kind of damage, being clearly, (to me), specific to the driveshaft, occurring from the crash. I see it as the other way around.

 

[autoteach]

Has anyone seen a dirt/sand/gravel tank slapper? I have seen it in whoops in motorcross, but not open terrain. The rear end was moving a lot like my 1968 c10 does at speeds over 60mph...but I did just find out that the PO did not tighten the axle u bolts so it was moving back and forth in the trailing arms. Now, if I had crashed the truck, would I have looked at the u bolts and said, " damn, the crash loosened my u bolts"?

 

[Dallara]

...The weakest link is typically the nut behind the handlebar...

You mean like when some owners inadvertently make some kind of "operator error" that causes a "hard starting problem" with their Super Tenere? Something so "random" that it can't possibly be the result of a mechanical defect, software coding error, etc. and therefore is most likely something like the "weakest link is typically the nut behind the handlebar"?

Or are you saying a rider is more likely to make an "operator error" that results in a crash than he might just starting his bike?

Dallara



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[GrahamD]

You mean like when some owners inadvertently make some kind of "operator error" that causes a "hard starting problem" with their Super Tenere?

::025::

 

[Tremor38]

As predictable as the day is long. Not every Chevy Vega motor needed a new block at low miles, but enough of this happened for it to be a problem. Now let's consider a problem that impacts rider safety (like cracking swingarms and separating drive shafts). Much less of this would have to occur for it to become a problem. This also happens on pavement, Mark. You acting as an unpaid advocate of BMW SS swingarms is getting kinda old, and I fail to see why you're so motivated to defend them.

Sent from my SC-03E using Tapatalk 2

 

[dcstrom]

As predictable as the day is long. Not every Chevy Vega motor needed a new block at low miles, but enough of this happened for it to be a problem. Now let's consider a problem that impacts rider safety (like cracking swingarms and separating drive shafts). Much less of this would have to occur for it to become a problem. This also happens on pavement, Mark. You acting as an unpaid advocate of BMW SS swingarms is getting kinda old, and I fail to see why you're so motivated to defend them.

Sent from my SC-03E using Tapatalk 2

Tenerator, I think you mean GS swingarms. You are thinking about something else. "Don't mention the war!" (if you're a Fawlty Towers fan you'll get this...)

 

[Dallara]

Tenerator, I think you mean GS swingarms. You are thinking about something else. "Don't mention the war!" (if you're a Fawlty Towers fan you'll get this...)

"Fawlty Towers" and German WWII military references aside...

I think he was saying "BMW S-ingle S-ided swingarms", as in not just on the G/S, but also the R1100/1150/1200RT,R1100/1150/1200R, R1100/1150/1200S, etc. All of them have single-sided shaft-drive swingarms of similar design, loading, etc.

Dallara


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[Dallara]

...This also happens on pavement, Mark. You acting as an unpaid advocate of BMW SS swingarms is getting kinda old, and I fail to see why you're so motivated to defend them.

Mark has sure suddenly gotten very, very quiet on this one now, hasn't he? O

He was pretty vocal on the subject there for a while...

Dallara



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[EricV]

Like every new change, we'll just have to see how it holds up over time. I can't say I'm impressed with their "water cooling" that amounts to little more than running coolant through the same passages they used to run oil through. The single sided swingarm is not a design preference of mine, but that doesn't make it bad, just sort of a pointless styling cue, imho. Maybe this time it will be the bomb? Or maybe it will be like the previous ones, a time bomb.

Been catching bits about how standing on the pegs on washboard gravel roads is not recommended. ??? Some headshake, apparently. Hopefully for BMW, it won't become known as the "Kevin Ash Model".

 

[GrahamD]

Been catching bits about how standing on the pegs on washboard gravel roads is not recommended. ??? Some headshake, apparently. Hopefully for BMW, it won't become known as the "Kevin Ash Model".

If it was a Suzuki TL1000, all the reviewers would pan it. Let's see how this plays out. I have a suspicion it will be put down to operator error this time.

Just for example..

"Like Ducati’s Panigale, the new GS has an automatic decompression feature that allows a smaller starter and battery for less weight"

They could have said...

"Just like a bunch of Japanese singles, the Super Tenere and a few KTM's ......bla bla"

This bike is starting to sound more and more like a Super Tenere all the time.

What will they think of next...Side mounted radiators, wet clutches, water cooling, ride-by-wire throttle, Standard ABS and high air intakes.... Oh wait...

Please YAMAHA I don't want 150HP and 12.5:1 compression.

 

[Dallara]

Like every new change, we'll just have to see how it holds up over time. I can't say I'm impressed with their "water cooling" that amounts to little more than running coolant through the same passages they used to run oil through. The single sided swingarm is not a design preference of mine, but that doesn't make it bad, just sort of a pointless styling cue, imho. Maybe this time it will be the bomb? Or maybe it will be like the previous ones, a time bomb.

Been catching bits about how standing on the pegs on washboard gravel roads is not recommended. ??? Some headshake, apparently. Hopefully for BMW, it won't become known as the "Kevin Ash Model".

You mirror my thoughts on the new Beemer G/S exactly, Eric. As I have often said, BMW's use of a single-sided swingarm these days is simply an answer to a question nobody asked... Nobody except the marketing ad-hype people, that is!

It actually made a bit of sense back when they used the SS swingarm in the pre-Paralever days. BMW was looking for a way to try and reduce the unsprung weight of their shaft-final-drive set-up to get closer to 2-sided chain drive swingarm bikes, and it worked. But as soon as they started with the unnecessary mechanical complexity of their Paralever designs all that went out the window. It has been proven time and again that there are better, simpler ways to control shaft-drive, crown-wheel induced shaft-jacking, but BMW continues to try and perpetuate the bizarre myth that their Paralever is somehow technically superior... And as with many things, if you keep saying it over and over enough times - even when you don't have the facts the back it up - people will gulp, gulp, gulp down the kool-aid and believe it as gospel.

It's that kind of thing BMW builds their entire motorcycle business on... the Telelever (a rip-off design, BTW)... The Duo-Lever (even a bigger theft of another's design)... Their ludicrous switch assemblies they claimed for years were ergonomically superior... Etc., etc., etc. For the most part it's all hype, all myth, all smoke and mirrors - nothing more. Some of it so ludicrous, so artificial, that it makes you wonder about the folks who believe the BMW bullsh*t and just how intelligent they are.

Interesting, too, about the Kevin Ash crash... BMW sure has been keeping an unbelievably tight lid on that whole episode. If it turns out a design flaw is what caused that crash it's going to really hurt BMW's credibility with that model. Could really hurt it in the marketplace if the word gets out from under the lid.

Dallara




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