Van suspension setup

[Vanada]

Just wanted to have a little brainstorm and share some (novice) thoughts here about suspension setup for vans.

My basis is a 2001 Chevy Express 2500 which right now has about 2 inches of extra space between the tire and wheel arch at the rear than at the front. (±6" at the rear / ±4" gap at the front). Obviously cargo vans don't handle great in general but my Dad was visiting a while back and had a lot better feel plus an extra 25 odd years of driving experience to give some feedback.

Here is what we determined:

• Front roll isn't too bad and basically can stay as it is. Front anti-roll / sway bar is standard.
• Rear is pretty wallowy but part of that is probably due to the fact that it's not loaded as much as is intended for a 3/4 ton van.
• Currently there is about 1.5" of space beneath the bump stops which themselves are 5" tall.
• The leaf springs are a pack of 4 thick-ish leaves with overload spring.

I've been keeping an eye out for an express factory conversion or passenger van for a while to take a look at the suspension and see how they are set up. In pictures they seem to sit a lot more level and not raised at the rear as I currently have. I think I did see a 1500 which had a 5 leaf pack of which each one was noticeably thinner than on the 2500.

Options for potentially improved handling are:

• Shim out the bump stops to remove some of that extra wiggle room.
• Remove a leaf (This idea got scrapped pretty quick since it'd probably stress the remaining leaves too much and go too low and/or prompt failure)
• Swap out the leaf pack for a softer set. Essentially that would be downgrading the carrying capacity.
• Add a rear anti-roll / sway bar. I know these are available but I don't know whether it would have a negative effect as well.
• Weigh the thing down!!
• Deal with it.

Anyway, I'd just like to hear if anyone has changed their setup, has any thoughts to add, can contribute info on their stock setup etc. Like I say, I'd particularly like to see what a stock conversion van has on it in terms of springs, bump stops and anti-roll.

Cheers,
Tom

 

[highdesertranger]

don't do anything until your build out is done and you are fully loaded. then look at your bump stops and drive it. come back then and let us know what you think.
DO NOT remove leaves
DO NOT shim the bump stops
DO NOT replace the spring pack until you do the above
a sway bar will not hurt anything
what tires are you running?
highdesertranger

 

[Dgorila1]

How old are the shocks? They may be worn out and making the ride harsher that it needs to be.

 

[Vanada]

Tires are 245/75R16 Nokian Hakkapeliitta LT2 which are a winter tire. Shocks are old as (probably the originals) but bumps aren't the issue.

 

[highdesertranger]

what's the load range on those tires? highdesertranger

 

[Gideon33w]

Conversion vans are more often found with the factory rear sway bar option.
Weight distribution is important but not until van is fully loaded/built.
Front coil springs and shocks are probably tired and sagging a bit.
If you still want to add rear weight go with a hitch tray and box setup.

Removing rear suspension components to lower it is NOT a good idea.
At least, not at this point since you aren't at load or using it.

If, when done, the rear is still too high you could do lowering blocks.

At the end of the day, it's a big-a55 van and will never handle well.

 

[Almost There]

At the end of the day, it's a big-a55 van and will never handle well.

It's not a case of 'not handling well', it's a case of it handling like a van. They inherently handle differently than a car or a pick up. If you want to have something handle like a BMW then get a BMW...

Agreed that you shouldn't do anything with the suspension until you've finished your build except one thing! If those are the original shocks replace them. They don't just help with bumps. If you think it's wallowing, it probably is and the most likely culprit in a van of that age is the shocks.

Then check your tire pressure. Make sure you're running the tires properly inflated for the load. I have to keep correcting both tire shops and the oil change places because they keep trying to underinflate my tires.

 

[highdesertranger]

lowering blocks only work on axle over spring designs. that van has an axle under springs design. again don't do anything until you are fully loaded. highdesertranger

 

[Gideon33w]

Ahh, good point

 

[Vanada]

Load for the tires is 3100lbs. Last inflation was done at a tire place following a screw in one tire to 55psi at the front and 80psi at the rear.

To be honest the build is done and the only things to go in are a couple of bikes so an extra 60lbs max.

Interesting to hear that factory conversions are more likely to have rear sway bars.

As far as the shocks go, yes they're old and rusty on the outside from wet weather and salted roads but for a 2001 it's still just under 100,000 miles so not terrible. I was told unequivocally by my Father (a race engineer) that the shocks aren't an issue. It just handles like a van and doesn't sit down because it's not weighted so I began exploring options. It's been interesting to learn about since I had no knowledge on leaf springs prior to a month ago. I think if I did ever do anything it would be to at lease try and make it handle better than it does currently. Not under any illusions here.

Anyway I was just mentioning my build as a case study. I intended to start a more general thread to discuss the various options that vans have for suspension and whatever y'all might have done. I take it most people leave it alone other than to replace shocks or unless a spring rusts out or something? I remember the 2500 being advocated by some on the forum for its higher capacity but if anything I feel I could probably have been good with the 1500.

 

[highdesertranger]

in that case put some good shocks on it. KYB or Bilstiens. and like I said a sway bar will not hurt anything. the 3/4 ton will survive hauling the weight around in the long run much better then a 1/2 ton. highdesertranger