TIRES: The Astro's OEM tires are a little bit too tall, and narrow for it's suspension. This makes for a bouncy ride, and very light, vauge steering. I have found out P225/70R15 BFGoodrich TA's make the little van handle pretty good, and also give a tighter, more responsive feel to the steering. I have gone to the P225/60R15 tires in October of 2001, which have an even lower profile. This size should lowers the ride height about a half inch off of OEM (lowering center of gravity), and and about a whole inch off the 70 series tires of the same type. This size makes steering a little more responsive, and improves cornering too. Overall, I'm really impressed at the slight improvements the lower profile tires give. One important factor to consider is that you loose a slight bit of load carrying capicity going down in size. The 70 profile tires have a 1700 pound capicity, where the 60 series are down to 1550 capicity. With the van weighing in at close to 4000 pounds "ready for the road", this brings the tire capacity right up to the payload capacity of 2000 pounds for the van. You may need to pay a little extra attention to the way you load up your van for a trip if you plan to tow, or carry heavy stuff.
SUSPENSION: Not too much has happened in the suspension department really, but one thing that was definitely needed right after purchasing this van was new shocks!!! The OEM ones that were on there were these skinny little things that were all worn out. The replacment shocks were the RANCHO RS5000.
These shocks have a lifetime warrany! And they came into good use. I have had these shocks on the van for about 100k miles as of this past summer. The rear shock were starting to get a little loose, so I took them back up to Truckin Thunder Superstore where I bought them. They exchanged the shocks with the reciept I kept without any hassle. The clerk there said that this was the first time anbody has ever returned a set. The front shocks are still holding up very well. Overall, I have been quite impressed with the performance and longevity of these shocks!
Their RS5000 shocks are a good all-around truck shock that work great on the Astro van, especially if you plan to do any trailering, or load-carrying. The RS5000 shocks have a neat valve that closes up when there is heavy movement. This allows the shock to give a smooth ride, yet maintain stability under poor road conditions, and heavy loads.
A few weekends ago, I picked up about 1500 pounds of gravel at the hardware store. With 2 friends, and a full tank of gas, we departed with over 2000# of load inside. On the way back, I hit a large rut in the road, and was sure the van would bottom out, but it didn't. It went down a little, then up a little, then I felt the shocks kick in, and tighten up. The little van never came close to bottoming. After arriving home, I noticed that the springs in the back were not even sagging that much, even with that much load! I want to see an owner of one of those front-wheel drive minivans even attempt this stunt!