Has anyone seen this before. Hit a pot hole 2 days ago with the wife on the back and there was a bang. I thought i had blown the back tyre until i got off and had a look..

 

That must have been some pothole. Do you know how to build a wheel?

 

Seen similar on a steel rim that rusted from the inside. Actually happened to an acquaintance while his girlfriend was riding pillion too, both ended up in hospital and I think she had some permanent damage. Glad you made it out ok
I have also seen aluminum rims crack from the spoke nipples pulling through the rim, may have been happening to you and the pothole cause the catastrophic failure?
Did you take the chain off or did the chain brake?

 

That isn't the stock wheel is it?
You should check the load rating on that wheel. Is the wheel from china?
If I couldn''t find any info on it, I would take the front one off too!
Can you imagine what that would be like if had happened to the front wheel. You wouldn't be here today!

 

Whoa!
As someone who's built countless bicycle and a few motorcycle wheels, that wheel had a serious flaw. Wheels are incredibly strong when put together properly or even close to properly!
If I had to guess, I'd say a few spokes were over tensioned.
Like others have said, at the least, take off that front wheel and remove the tire and examine it closely.
Glad you guys are OK.

 

Too late for the "ping" test.

 

Yes, it is now "pung."

 

I built that wheel and used a spoke torgue wrench,, But i am now starting to think it might have been over torqued. not sure, The wheel rim is from China.. not sure ifg that has any bearing on the breakage or not..

 

The chain just came off, when he wheel split. Yes, we were very lucky as we were doing 140 KPH 2 mins before, just slowed right down for corner then see the pot hole too late,,

 

The wheel rim is from China, but hub and spokes are Kawasaki..