Some advice on a Chevy Suspension Upgrade

[phantomjock]

booster -

As always, good words. Thanks.

Cheers - Jim

[rowiebowie]

Originally Posted by phantomjock

rowiebowie-

Looking forward to the long-term analysis. Going through this thread, it appears that your "lift" was all shock extenders, then the 2-1/2" lift kit? Kit details? You haven't mentioned Air Bags. Installed - or no? The kit providers?

If you have a BOM to go with it - that would be really Great! I'm looking for a "Sightly Lifted Express Chassis."

Cheers - Jim

My lift was a Supreme Suspensions kit. Front Coil Spaces, and rear Leaf Spacers. Thus the need for their lower shock mount extenders so I could keep my same Koni FSD shocks. I added Sumo Spring black bump stops in front and their yellow bump stops in the rear. Everything else is stock.

[phantomjock]

rowiebowie -

Thanks. That approach looks simpler than the Air Bag mod others have used. Starting with longer shocks might bypass the need for extensions, I reckon.

Still a bit currious to the ride height measurements you might have. I can check and compare your 3500 Airstream to my 2500 RT easily enough, and the RT vs Chevy OEM heights too. I'll factor in my upsized tires, 265x75R16. I'm running 35.5" Front, 36.0" Rear.

Your satisfaction with the results is reassuring, just as the others with Air Bag mods are, like booster pointed out. Nice to have options (along with informed results) available to consider.

Thanks again.

Cheers - Jim

[booster]

Originally Posted by phantomjock

rowiebowie -

Thanks. That approach looks simpler than the Air Bag mod others have used. Starting with longer shocks might bypass the need for extensions, I reckon.

Still a bit currious to the ride height measurements you might have. I can check and compare your 3500 Airstream to my 2500 RT easily enough, and the RT vs Chevy OEM heights too. I'll factor in my upsized tires, 265x75R16. I'm running 35.5" Front, 36.0" Rear.

Your satisfaction with the results is reassuring, just as the others with Air Bag mods are, like booster pointed out. Nice to have options (along with informed results) available to consider.

Thanks again.

Cheers - Jim

You have the 2500 170 which is lighter and shorter so less information around, but 35.5-36.0 is pretty typical of what many of the early lifts with the Tufftruck and Moog springs were running, including our 190. Tufftruck quit making the springs and Moogs have changed so they come out more in the 36.5" height in the front. With bags the rear is adjustable usually up to about 37' or so on 190s.


Most of the clearance issue on the Roadtreks is the valve/macerator area that is about half way between the axles so at the center bottoming worse spot. The shorter 170 will be less likely to high center bump than a 190 though. We have found the 35.5-36" wheelwell height to be sufficient to prevent hitting on driveways and other rough areas we get to, but we don't do rutted fire roads or that kind of thing.


I think that some of the personal choice stuff with springs and such is because the different people have different ideas of what feels best. For instance, I like longer travel/less progressive spring rates as longs as the shocks and sway bars are controlling the handling well (handling part very important o me). Others don't mind or prefer the shorter travel/more progressive feel in their vans. The shorter/progressive springs would normally need somewhat less attention to shocks and swaybars as some of that is helped by the extra stiffness, so if you are not super critical on handling it can fine that way.


In general, springs tend to be less progressive than urethane bumper style "bump stop" units and airbags will usually be less progressive than either of the other two.

[phantomjock]

All very interesting information. And yes, the lighter shorter 1702500 Chassis does have that one advantage - less opportunity to High Center Bump.

I was curious what the service life the Sumo Springs might be? My OEM bump stops are totally shot on the front, so in need of replacement. Just wondering if the $umo $prings will get me 80-90K service - or?

Any thoughts?

Cheers - Jim