Bouncing

[2500ltd]

Hey all.

Own a 2021 2500 Cummins Limited with no air suspension. I only use it to two my 25' Airstream (975# TW and 7300# GWVR).

I love the truck. We do a lot of long trips and the range is awesome. It's also very reliable. Haven't had one thing break down in over 30K miles.

That said, I'm not a fan of how much it bounces a lot over bumps and potholes while towing and most importantly, the resulting stress on my trailer.

I'm contemplating two mods to improve this based on my readings:

-Change the shocks. My local guy installs Napa shocks. He says they're Monoes and would be more firm than the OEMs.

-Change the Transforce AT tires for LT tires. Don't know which brand yet.

Are these the right changes and will they make enough of a difference?

Thanks for your help.

P.S.: I have a BlueOX WD hitch. Trailer is level and the truck front axle height is within RAM manual specs when hitched up.

 

[LikeABoss]

What PSI are you running? I don’t know if a tire change will make a huge difference but you don’t need 80psi for that weight unless you have a lot in the truck too.

I would go with Bilstein 5100 or 5160s myself.

 

[2500ltd]

What PSI are you running? I don’t know if a tire change will make a huge difference but you don’t need 80psi for that weight unless you have a lot in the truck too.

I would go with Bilstein 5100 or 5160s myself.

I’m at 65 which is the sticker recommended pressure on mine. I tried running lower, 55, and it didn’t make a whole lot of difference.

 

[AH64ID]

I’m at 65 which is the sticker recommended pressure on mine. I tried running lower, 55, and it didn’t make a whole lot of difference.

Have you ran over a scale to check your axle weights? If not then I would suggest it and then running the proper pressure for that load based on the load and inflation tables.

A lot of bouncing can also mean an improperly adjusted WDH, even if you’re in spec. The best way to setup a WDH is on a scale.

I personally wouldn’t run NAPA or Monroe shocks and would look at Bilstien 4600’s. I don’t think they make a 5100 for stock height.

 

[2500ltd]

Have you ran over a scale to check your axle weights? If not then I would suggest it and then running the proper pressure for that load based on the load and inflation tables.

A lot of bouncing can also mean an improperly adjusted WDH, even if you’re in spec. The best way to setup a WDH is on a scale.

I personally wouldn’t run NAPA or Monroe shocks and would look at Bilstien 4600’s. I don’t think they make a 5100 for stock height.

Thanks and yep, I’ve done the weighing. Transferring 300# back to the front axle bringing the truck 100# from its unlashed up state. No expert but I think the WD is nicely tuned.

For Bilsteins, the right model would be the B6 4600?

 

[AH64ID]

Thanks and yep, I’ve done the weighing. Transferring 300# back to the front axle bringing the truck 100# from its unlashed up state. No expert but I think the WD is nicely tuned.

For Bilsteins, the right model would be the B6 4600?

You’re saying the front axle is 100# heavier from the WDH transfer? Or 100# lighter?

Yes, that’s the correct model.

What is your total tongue weight? And tongue weight percentage?

 

[NMRam]

The coil spring suspension on the 2500’s makes for a nice unloaded ride but isn’t the best for hauling heavy loads. New shocks won’t support the weight any better, they’ll just dampen axle movement.

Your best bet would be to add some airbags inside the coils to help support and stabilize the weight. Ride Rite has some that are a pretty simple install and are relatively inexpensive. Air them up when hauling, reduce air pressure when empty and you maintain factory ride. One thing with the airbags, I prefer to plumb the air lines to each side separately. If you tie them together, air can shift from side to side when cornering.

 

[AH64ID]

The coil spring suspension on the 2500’s makes for a nice unloaded ride but isn’t the best for hauling heavy loads. New shocks won’t support the weight any better, they’ll just dampen axle movement.

Your best bet would be to add some airbags inside the coils to help support and stabilize the weight. Ride Rite has some that are a pretty simple install and are relatively inexpensive. Air them up when hauling, reduce air pressure when empty and you maintain factory ride. One thing with the airbags, I prefer to plumb the air lines to each side separately. If you tie them together, air can shift from side to side when cornering.

I would recommend airbags on the 2500’s, but not inside the coils. Get the ones that mount outboard of the coils for greatly improved handling.

 

[2500ltd]

You’re saying the front axle is 100# heavier from the WDH transfer? Or 100# lighter?

Yes, that’s the correct model.

What is your total tongue weight? And tongue weight percentage?

I’m saying the front axle is 100# lighter with WD applied than the truck without anything on the ball.

My trailer comes in at 6450# and the TW is at 1000#. That’s on the higher end I realize that. Could be the culprit in your opinion?

 

[AH64ID]

I’m saying the front axle is 100# lighter with WD applied than the truck without anything on the ball.

My trailer comes in at 6450# and the TW is at 1000#. That’s on the higher end I realize that. Could be the culprit in your opinion?

I like 13-15% TW and you’re at 15.5%, so it should tow very stable.

I’d start with free adjustments and try reducing the WDH by one setting and seeing if that helps, from your numbers that would put you closer to 50% restored.

Shocks and airbags are a good place to start spending money, but you don’t want to use the airbags in lieu of the WDH. They can work very well together thou, it just takes a little more effort in adjusting them.

 

[2500ltd]

I like 13-15% TW and you’re at 15.5%, so it should tow very stable.

I’d start with free adjustments and try reducing the WDH by one setting and seeing if that helps, from your numbers that would put you closer to 50% restored.

Shocks and airbags are a good place to start spending money, but you don’t want to use the airbags in lieu of the WDH. They can work very well together thou, it just takes a little more effort in adjusting them.

Thanks for this.

if I understand what you’re suggesting, air would help absorb suspension movement once the trailer is properly hitched up and WDH dialed?

 

[AH64ID]

Thanks for this.

if I understand what you’re suggesting, air would help absorb suspension movement once the trailer is properly hitched up and WDH dialed?

Yes it can, since compression increases the airbag spring rate and expansion decreases it. Same principle as to why they improve cornering stability when plumbed independently.

 

[2001WS6]

I air bagged my 2018 PW. It seriously helped pulling this 26' enclosed trailer.

Crappy pic, it was mid February and got nailed in a snow storm. lol

 

[flan]

Poor truck.

 

[mkmsr]

I say good on ya, that's what trucks are made for. Not to be shiny and pristine!

Sent from my Pixel 6a using Tapatalk

 

[2500ltd]

Yes it can, since compression increases the airbag spring rate and expansion decreases it. Same principle as to why they improve cornering stability when plumbed independently.

Thanks again. Would Sumo springs achieve the same result?

 

[AH64ID]

Thanks again. Would Sumo springs achieve the same result?

Similar, but not the same.

I really like my sumo springs up front, but airbags are the better option out back IMO.

 

[2500ltd]

Similar, but not the same.

I really like my sumo springs up front, but airbags are the better option out back IMO.

Thanks. For my purposes, would your reco I put sumos and/or air bags front and back or just back?

 

[AH64ID]

Thanks. For my purposes, would your reco I put sumos and/or air bags front and back or just back?

I would start with airbags and go from there.

The front sumo’s go well with the Thuren Active Rate anti-sway bar, but those aren’t for what you’re experiencing.

 

[Razzman]

Late to the party here. I have the same issue on mine, porpoising. 850lb tongue weight and 100% weight distro. I've reduced distro but makes no difference. Trailer tows perfectly otherwise and this hasn't been a big deal until the recent trip over the worst road I've ever been on, enough of that! I'm putting on air bags, just gotta figure out which ones.