Hope this is in the right section. On a 3500 dually, what tire pressure are you running. I have a slight vibration at 70-75 mph and the dealer said to drop the pressure down to 60lbs. I tow a fiver with a pin weight of 3200lbs, and on a previous GM dually I ran 70 front--65 rear. every thing worked well like that.
The door panel says 80front--70 rear (I think, but that much is sure to ride rough).
Thanks,
Cary

 

I have a 2006 dually and run 65 psi on all tires year round and pull a fiver in the summer seems to be ok for my tire wear but I do rotate about every 5k-6k. It is not a daily driver only used mostly in the spring and summer.