I have respect for the Z400. I have now seen 3 roll down a major dune and having minimal permanent damage. Clip the plastics back in, reinflate the tyre and voila! Check out the pics I took on Sunday of a Z400 rolling down the dune at http://www.e-dirt.co.za/weekend.asp

 

Put some paddles on that thing and he won't have that problem again. The sand looks way too soft and fine for dirt tires. JMO

 

Tyres are extremely expensive so most guys just have dirt tyres or those maxxis you can change over sand or mud. This guys mistake was that he had run out of power as he flipped round and did not have enough momentum and the tyres dug in and the quad flipped over!