Chevy & GMC Vans

Long time no post, van has been great, AWD working great. Anyway time for new tires, found different OE wheels in boneyard 15s and need to know the tallest 15 AT tire size.
Also wondering if there is anything a dealer can check or do if I pay the extra for a dealer done tuneup? Luvin the Astro

Glad to hear your vans been treating you well. As your sig says "too stock" you don't have much wiggle room when it comes to tire size. You can mount 35" on the rims but that's as far as you'll go. Stock suspension really limits tires. I have a2" body lift and run 235/75-15. The 75 is a percentage of sidewall height compared to width. So a 235/75 will be taller than a 215/75. It depends what you want to do. You can go with wider than stock and adjust you sidewall height accordinly. something like 235/60-15. It's gonna depend on what you want it to looks like and what you plan on doing with the van.
If you have someone tune it for you have them change vacuum line while they're in there. Biggest PITA with these vans when vacuum lines start to fail and cabin airflow starts going haywire. Let us know what you decide

I'm currently running 235/75R15 (29") tires with no lift or tire clearance mods on my 1999. It works by running tires that aren't aggressive on the outer edges.

If you are handy with tools, tune-ups are fairly easy on these vans.

well i got AT owl p225/75r/15s rubbing a little only on some medium turns. What is the talk about torsion bar tightening giving at little room to the front end.
Any bad things about it? use the van to go fishing, sand, some forest rds, no climbing in Louisiana, no rocks except oyster shells.
Also did idler arms and pitman arms and sway bar bushings,am going to do shocks after vacation. That might give me some extra room also. I want to spend a little more on the shocks than OE. Anyway when they do my brakes I wanted them to possiby do torsion bar tightening. Good idea? Pics of van tomorrow !

Yes you can crank on your torsion bars. There are varying schools of thought on this. Most bad things happen off road. Mostly, cranking your bars changes the front end geometry. This causes front end parts to wear quicker. Check your ball joints. If they are original and are still riveted to the upper side of the control arm, you can change ball joints and install them on the underside of the control arm helping restore some of your original geometry back. And you will need an alignment for sure. There are tons of posts on this. Google it and see all the astrosafari/s10 posts. Read up on it and then make the call