I have to agree that IF that 70% thing is true, it would have to be due to weight transfer. But, nice thing about lockers is you don't need momentum to tackle obstacles. You can take things real slow. you haven't filled out your profile so I don't know what kind of tcase you have. But, if you can unlock your hubs, I will assume your rig is not a fulltime 4WD unit. If it isn't fulltime 4WD, you should be running with your hubs locked on the street anyway. That's a bad thing.
I would never ONLY put a locker in the front. I have Detroit lockers front and rear in my 10 bolts. one of the real advantages of my rear locker is that I can get through an obstacle in 2WD that others struggle with in 4WD. I soend most of my time offroad with my hubs locked but in 2WD. I only slap it into 4WD in extreme situations. That reduces my risk of breakage of front parts due to my locker.
As far as driving characteristics of the locker in the rear on the road, it is something you get used to. You had to get used to driving a 4x4. You had to get used to driving a lifted rig. You will also get used to the characteristics of a rear locker. Not that big of a deal.
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