Tires: Tires, dodge dealer, dodge dakota

Question
I got a Dodge dakota 4WD with currently P245/70/16 106S tires on. Now I got a set of LT 245/75 R16 RWL/LBR LRE 120/116S tires I would like to put on, but the guy from the tire shop says they would be to heavy and would damage the diff etc. But I got this set from a dodge dealer, so I wonder who is right?

Answer
Gunnar,

LT tires are quite a bit heavier than P tires, and while the tire shop gave you incorrect reasons why you shouldn't use LT tires, they are correct in their answer - you should avoid using them.  The real reason is that you would need to use 17 psi more pressure to get the same load carrying capacity - and that is potentially damaging to the suspension, since the tires won't absorb the bumps as well.

BTW, I wouldn't expect a vehicle dealer to know much about tires, just like I wouldn't expect a tire dealer to know much about transmissions.