Who really cares who's physically stronger? These kind of threads are ridiculous to begin with. They're all career criminals and they all have members more than capable enough to commit brutal acts of violence (including murder).

Adding to that: it all depends on the location. In NYC the bikers are nowhere near the mobsters. In some other place, for instance California or Texas, bikers would run the wiseguys out of town. You often hear these laughable claims from 14 year old kids that go like: "Russians and Albanians so much stronger than Italians blablabla". While the last time I checked in NYC it were the Russians kicking up to the Italians. As for the Albanians like the Rudaj gang (who had as many Italian and Greek members as they had Albanian ones- check the arrests if you don't believe me) who tried to take on the mob...where exactly are they now? That's right, rotting in jail and they don't have any street presence anymore. In other cities throughout the world it may be different. Consensus: these "mob ethnic/cultural group 1 vs. mob ethnic/cultural group 2"-battles are ridiculous.