I got an email asking this question so I thought I would post it.

"For many years I talked to many engineers in this country, Germany and Italy. When the X frame was coming in they all agreed that is was good for set up but was not as stable as front swing out outriggers.

Love to hear what guys tell you there thoughts are on stability of front swing out outriggers and the X frame."

Based on the post of the pump in Canada, I believe I would be wondering about the rear outriggers with internal tanks, and exactly how they are constructed. How do those gusset plates break, and first and foremost based on the pictures, why do we not have penetration of the weld, whether from the manufacturer or an outside source. Scary scenario.

I have one of the original 36 metre Callaghans built by Brian snr with front x legs and slide out rear, that is without a doubt the most stable machine ive operated in 14 years! The only machine ive operated with swind legs was a 1990 Schwing 32, once you got it 3/4 way out it would buck and shift on its dunnage, not a fun day on that old girl!

X leg is the better config but the swingouts are much more stable , but having said that there all engeneerd to stay upright as long as your doing the right thing!! 

(In my humble opinion ;-)I don't think you can say that ALL the x designs are more stable than swing out outriggers or the other way round...  I drove a 32m with slide legs at the front and rear for a while and that one was dancing like a maniac if you where all the way out over the side. Customers realy thought it was gona tipp. But a 36m with those types of legs was a great and stable machine. The 52 schwing with swingout outriggers front and rear i thought was quite stable to if you drive it right.

Only feeling I have. But its just a feeling.. is that the ''round'' slideout riggers from for example a 45 schwing are less stable. That was at least the least stable machine i ever drove. But I only drove it a few times.. maybe I did something wrong ;-)...

Ill have to say front swing.

the old schwing 42m with the swing out front and rear was the most stable machine Ive ran , the schwing 58sx was also a stable machine with the right dunnage and pads, the putzmeister pumps to me seem a little more light on the outriggers but thats just me, to answer your question I believe it all depends on the machine, the design, and the operator, theyre all "designed" to keep it from tipping its usually mechanical,human error that causes accidents and even most mechanical can be found to be human error at some point.

well as the calculations are done, it should make no difference.

I run a 1985 shcwing 36, and that is definitely a stable outrigger system, but can be tricky to get perfect on jobs.  Its also a heavy pump.  If you were to take a new schwing 41 sx and compare the spread charts, the front spread is about the same, but the back spread on the 85' 36 is wider then the new 41 meter.  I can't wait though until I get the chance to run a newer truck someday because that truck can be an absolute pain in the ass to open on tight jobs.

i believe the question in every ones mind which system is better an dto tell you the truth they are both equally stable but the fact is this accident could have been prevented !!!! ive seen the pump upclose the accident happend 5 minutes away from my house!!! i went on site with the ministry of labour !!! the outrigger failed in two spots!!! cracks that had six months or more worth of rust in them!!!! there is no price on safety my friends and now we see why!!! companies that cut corners!!! and avoid annuall boom inspection here is your wake up call!!! or your one get out of jail free card gentleman!!!do not kid yourself the owner could in reallity go to jail for this here in Canada!!! god bless the men that were hurt that day!! our thoughts are with the families!!!

Mike Morrison!!!!