Chevy & GMC Vans

I am building a camperised AWD 1999 Safari for OVERLANDING. Mostly for hiway use, but also wanting some serious off road capabilities. I have radiused the wheel wells, and done a 2" body lift so should have more than enough clearance for larger tires. I want to leave the front torsion bars alone, to preserve driveshaft angles, minimise wear, and keep the center of gravity as low as possible. However, since this van has 3.42 gears, so I also want to stay with smaller diameter sizes, even though I may have more than enough wheel well clearance.

I want STIFF side walls, to minimise sway and wind wander, which means very few choices in 15" tires, although there are some interesting possibilities in LT 235/75/R15. I have been investigating switching over to 16" rims and tires, which opens up a much larger selection of E / 10 ply rated tires, which will give me the stiff side walls I want.

BUT,
even though I plan on running BILSTEIN shocks, and HD rear springs, and completely upgrading the front end with MOOG components, I am wondering about the long term durability of the front suspension and steering parts with HEAVY tires off road??? What are the weak spots to look out for and beef up?

My local tire shop is pushing me towards the Goodyear Wrangler DURATRAC tires, which have Kevlar side walls, as the best choice for my use. The LT 235/75/R15 size, 29" Diam, load rated 2000 lbs each, weigh in at 35 lbs each. The same tire in a LT 245/75/R16, 30.5" Diam, is E rated at 3000 lbs each, and weighs in at 45 lbs.

Any suggestions and personal experience with these size tires on an AWD ASTRO/Safari??
thanks in advance,
LAZ 1

When I replaced the stock size 215/70-16 Yokohama Geolandar A/T-S (29.2", SL, 1764 lbs, 30 lbs) with 235/70-16 Geolandar A/T-S (XL load, 2149 lbs, 34 lbs), the ride improved and felt much more controlled, especially when loaded. The van (or I) didn't seem to notice the 4 lbs extra but the tires were a vast improvement overall. I also had Bilstein HD shocks at the time and a freshly rebuilt Moog front end (sans control arm bushings).

When I went from 2" lift to 4"+, I installed the 245/75-16 Treadwright Wardens (30.7", E load, 3000 lbs, 50+ lbs), the van really noticed the weight (and diameter) increase and mpg decrease. While it's great to have heavy duty E-load tires, I am never going to inflate these things to anywhere near max inflation (80 psi) and run them around 38-40 psi to keep things comfortable.

Excepting off-road durability, the XL load rated Geolandars did everything that was asked of them, stable, smooth and quiet with excellent traction wet or dry. I wouldn't hesitate to run another XL tire on my van if I were never going to venture very far off pavement.

A 29"-30" diameter tire is a great all-around tire size for our vans. I would consider starting with 29" C-load tires before jumping full bore into the E-load tires. Does your tire shop have a policy where if you don't like them you can exchange them for something else?

When I replaced front suspension/steering components before the lift, I didn't replace control arm bushings and the larger, heavier 31" tires definitely helped to finish off the lower bushings. If you're replacing with Moog parts anyway, then the front suspension/steering shouldn't be as much of a concern.

With the Rancho RS9000XL shocks set between 6-8 for a firmer ride, my van is very stable, even with lift and rooftop tent. The Bilstein HD shocks are better quality and nicer overall than the Rancho and the durability can't be beat.

Have you thought about installing a Hellwig rear swaybar to minimize sway?

I just mounted up some Cooper AT3s in the lt235/75/15 flavor and they ride quite nice . I am staggering the tire pressures 42 lbs up front and 38lbs out back with it loaded for a weekend away. There is still more load capacity left if I need it .

My wheels weigh something like 130lbs each and I beat the crap outta my van everyday. I replace ball joints and idler arms about once a year now. MOOG is crap for bushings. Buy poly bushings. Stuff wears out no matter what your tires weigh. I suggest buying an extra set of idler arms for the toolbox and away you go.

Do an internet search on DuraTrac sidewall issues before you buy them.