Pics of before and after (shows me on it, day before). A pic of the small bump it hit, where my helmet is sitting.
If you click on any picture you will go to a Hi Resolution pic so you can zoom in on detail:
Closeups: Suspicious area of casting with granular composition inconsistent with the surrounding material is circled.
This is always on the lower side (high stress side), on all 4 pieces of material. Always on the inside lower corner.
These pictures are not clear enough to determine this, but in person it is very noticeable. I have had 2 different BMW dealers see this, plus my own metallurgist informally, plus several knowledgeable riders on the LA Barstow to Vegas ride, one of whom works with a scanning electron microsope professionally.
The metal clearly had a "catastrophic" failure, nothing else can be determined with high confidence without a professional cleaning and analysis.
1. Right side, front. Also circled is hole that is weak point, and a crack leading to the right side:
2. Right side, rear piece:
3. Left side, front:
4. Left side, rear piece:
AGAIN, this bike has only been offroad a total of about 10 days.
Another DIRECTLY RELATED ISSUE, is the OEM rear shock!
From day 1 it always exhibited bottoming of the shock, despite setting its hydraulic preload circuit to the maximum amount.
This is for a 190 pound rider, no passenger, no luggage, and only mild off road bumps and dips.
Many XCountry owners on AdvRider.com have complained about this poor shock and the resulting bump stop breakdown, here is another owner's picture, not just mine:
On my very first ride off highway, the shock bottomed on a very simple bump and ripped off my rear fender and license plate, something I had to pay for and modify to be stronger, myself.
But half of that problem is because the rear fender license plate area is not supported at all and flops all over the place, not just because the shock is poor.
Clearly this bike was marketed for both street and enduro off-road riding, but the advertised 8" of rear wheel travel feels more like a soft 4" travel shock from the 70's!
My solution was just to slow down on any bump as I did not want to damage the rest of the bike, while on group rides everyone would just go by and leave me in their dust.
I had complained about the poor shock before and tired of fighting the dealer while it was in warranty.
I just lived with this as a limitation of the bike until I replaced the shock with a proper aftermarket one.
Remember I received this bike mid-March and the warranty ran out mid-June, and I left on a trip in late May, so I only ridden it 2 days off highway before the warranty expired.
Just after the warranty expired, I reluctantly ordered a $1000 Wilbers shock made in Germany and specifically tested for this bike.
When I pulled the OEM shock off I saw fluids had leaked around the top of the rod and that the big black preload knob would just spin freely.
Clearly I had blown out the hydraulic preload circuit. MANY have complained about this problem forcing them to buy a new shock.
THE POINT IS: I believe it is clear that the faulty OEM shock has contributed to the weakening of the swingarm. Had it been replaced when I complained about it (and only 4000 miles on the bike), this may have been prevented.
Or it may be the OEM shock even if working was too weak to ever perform well. In any event, I paid for a $1000 replacement shock when I think BMW should have provided a reasonable shock to begin with.
My OEM chain has also been very stressed when the swingarm snapped, stretching it with great force and rubbing on the bottom of the swingarm. SEE second picture ABOVE.
Who knows about the stress on the countershaft (and front sprocket) as well.
The rear tire dug into the plastic fender well, melting it down until the bike stopped.
This should be replaced. And how stressed was the tire knobs - it and the wheel and rotor should be examined at the very least.
This swingarm failure is a safety issue and I certainly hope BMW recognizes this. Thank you. -matt