I've had this B1500 Van w/ a Regency High Top Conversion since it had 3500 miles and it has always worn out tires prematurely at about 25-35 k miles. After the 1set, I upgraded to 6ply rated tires and installed heavier shocks to reduce the sway. It did reduce the sway somewhat, however, the tires have still worn out prematurely. I have always been vigilant about keeping the tire pressure at the manufacturer spec of 32-35 psi. I recently decided to increase the cold tire pressure to 42 psi to see what affect it would have. It does handle better, but the tires are worn enough that it's time to replace them again. The van came with 235/75/15 and I haven't deviated from that. The last set were Cooper Discoverer H/T, load range C. I am asking for recommendations for tires and ideas on tire pressure. Any ideas on suspension modifications you can offer would also be appreciated.
Thanks for your help.

 

How are the tires wearing? Is it even wear across the tread? Or do you have a strange wear pattern?

 

They all wear on the outside edges. In the sidewall is fairly worn as well so I'm sure the tires are rolling over in the curves. That's why I think the tire pressure was too low and may not be strong enough sidewalls and may need 10 ply tires instead of 6 ply. The back right always wears on the inside first and is usually showing belts before the others are worn enough to replace

 

The only reason why I haven't put 10 ply tires on it is that they are a lot more expensive than 6 ply tires and I am concerned about losing the nice smooth ride that I have now.

 

I would be tempted to put it on an alignment rack, and see how things looked.

If that doesn't yield anything interesting, it may just be the way things are, with a large, heavy, tall, van...... The hightop alters the center of gravity on that, and probably tends to make it lean more in the corners.

I don't think 10 ply tires are really necessary, but, maybe going to a load range D tire would be an interesting experiment? I might also be tempted to bump to a slightly wider tire. Stick with the same overall diameter, so the speedo remains accurate, but, go with some 70's, or even maybe 65's..... Depends on your rim width, and what they will support.

 

Mine is a Mark III Hi Top and there are two layers of stickers on my door jamb. I think the second one addresses the correct tire pressure for a Hi Top.
Front: 37Psi / Rear: 41Psi

Sorry if I posted this 3 times; Haven't found the correct reply button if there is one.