what is the difference in stress on the trail that makes a smaller d30 axle on the front less prone to breakage compared to a d35c on the rear?

the physics of this is confusing to me because of course even though the axle shafts are minute in size difference between the two axles, the smaller axle i would think under load (4x4 wheeling) be more prone to breaking....but im sure more people have seen a d35c in the rear go well before the d30 front.

someone please shed some light on this topic

 

Usually when people snap d35's it's because they get the rear tries spinning rear fast going up a hill or something, then they slide back down and all the weight is on the rear tires, meaning more traction suddenly, and all the kinetic energy of the spinning tires is just too much for the axle. This situation doesn't occur as often for the front axle. Here's a good example

 

The 35 is semi floating which means all the weight is on the axle shaft and when a load is put on it it has to pull that and carry the weight. The 30 is full floating meaning the bearings carry the load and the shafts only have to turn the wheels. There is much more to it but that is the basic jist of things.

 

When I asked why the D-35's are weaker I learned that the axle housing is weaker, and flexes causing breaks, combine that with weight transfer, and what XJmarc wrote and the rears are going to see more stress then the front and break more often