Sumo Spring choices

[Dana H]

I haven't purchased yet,
What color did you install?
Are you satisfied with them handling bounce when loaded?
Since you have air gap I'll assume unloaded ride is unchanged.
Again thanks for everyone's input. Getting closer to a decision.

[MoonShadow_1911]

I haven't purchased yet,
What color did you install?
Are you satisfied with them handling bounce when loaded?
Since you have air gap I'll assume unloaded ride is unchanged.
Again thanks for everyone's input. Getting closer to a decision.

Who are you asking? You can use the quote function like I have to address the person you are responding to.

[pilotpip]

I would try LT tires before anything else. It is amazing how much more stable they are when towing than P rated. The ride gets slightly rougher but you can always air them down to around 50 when not towing.

[jproctor9]

Black Sumos on the F150. No spacer so there is about an inch before axle contact. No change in unloaded ride.

Blue Sumos on 2400BH. Trailer "calmed down" quite a bit when towing. Added benefit is dampening movement when parked.

Load Range E tires will impact daily driving but make a huge improvement when towing. For me it's worth it.

[Redapple63]

I am running the Timbrins on my truck (2019 GMC 3500 4X4 srw diesel). I love them. I can’t speak for the Sumo’s, but the Timbrins are supposed to have about 1-2 inch gap between the axle and bump stop. The intent of both items is exactly the same, they just use different materials to accomplish.

The installed gap for the Timbrins is to provide a stock unloaded ride, but an improved ride when loaded and compressed/engaged. I don’t think you could go wrong with either, just need to decide your preference of how they work both engaged and not. The Timbrins do have a minor impact when going over big bumps, driveways or say a speed bump, but otherwise stock ride.

I love my Timbrins, once you make your decision please let us know which one and how you like them.

Bill

[COGrandDes]

I've been looking into the Sumo Springs for our truck to help improve the ride and minimize the bounce.
First of all I feel as though the the WDH is well tuned.
Towing the TT I have minimum sway issues and otherwise quiet satisfied with the overall handling.

The truck's rear typically drops about 1-3/8"
The trucks front rises about 1/8"
The tongue weight is typically around 960# (13%)
These are the actual Cat scale results.

The truck is still on the original P rated tires which I run at 5# higher to increase stiffness.
When it becomes necessary I will replace with higher load rated tires, probably Nitto.

The normal ride of the truck without the TT is very comfortable.

I believe the short wheel base contributes to bounce/rebound.
This was all more noticeable on our last trip which the longest to date of ~1700 miles'

After researching and searching the archive here I sort feel that the SUMO Springs may be the way to go to improve the ride.

While they come in 3 sizes I believe the Yellow will be too stiff for my application.

The Black seem to be the probably choice but I'm a little concern that it may stay energies to some extend with out the TT and create a stiffer "normal" ride. They are rated for 1500# @ 50% compression and with the 960# tongue being roughly 64% of its capacity. While I did contact Sumo they simply said stated the Black would work.

The Blue is rated for 1000# @ 50% compression. With that said I'm leaning towards this one.
I seems like it is less likely to affect the normal ride without the TT but still be in range to handle the addition lounge weight of 960#, but that puts it @ 96% of it's rating.

There is one piece of data that I think would be beneficial is what would the height of the compressed Sumo Spring when loaded with the TT. I would expect it to compress an additional 1- 3/8" but don't really know where that is in relationship to the spring height with no extra weight on it.

With that I would like to ask the list for their experience/guidance.

BTW I looked at the air bag systems and RAS system and didn't feel that my issues fell into either one of these options.

I think there are multiple things you can do to address this bouncing. I had lots of bouncing and chucking on some of my fifth wheels in the past and tried multiple things. I even tried the Timbrens as others have noted for a couple short trips and then returned them. They are easy as people have noted to install but I did not like the harshness of the ride when they would make contact with the frame and axle. I fell in love with the air bag system with wireless compressor for the rear. Sure, it takes a couple hours to install but you can tune the air to get the desired ride no matter what you are hauling or pulling. I feel it's a much better system for the investment....at least it was for me. Even my wife notices a big difference between the two options. Also, adding shocks to your camper would also likely help with that bouncing as well. The forums are full of people that have had great success with installing the shocks as well. The point is...there are options each providing many people happiness.

[Dana H]

Sounds like you put spacers in??

I have the exact same truck as yours and mine have air under them

Slappy,
Which color Sumo spring did you go with?

[tamrick]

"....According to my calculation based on the CAT scales is there is about 600# more weight on the rear axle with the WDH engage oppose to not engage. Providing I'm interpreting this correctly:
With WDH ENGAGED based on CAT Scales:
Steer axle: 3520#
Drive Axle: 3560#
Trailer Axle: 6820#
Total Axle: 13900#
WITHOUT WDH engaged based on CAT Scales:
Steer axle: 3120#
Drive Axle: 4160#
Trailer Axle: 6660#
Total Axle: 13940#
..............................."

What is your Steer axle weight of the truck only, no trailer? You mentioned your front height within 1/8"; is that after WDH engaged and if so, 1/8 higher? You may be putting too much weight back onto the front axle (tends to bounce the rear more).

Your tires may contribute to the bounce if you have 17 or 18s, so I would air them all up to max cold before towing. If your tongue weight is right at 960lbs, adding passengers and other stuff in the truck will put you near your max payload. That is why I make the suggestion.

Last, if your tow vehicle is the 2018 in the signature, your shocks may be wore out. I used to tow a lot at max truck weight when I had a bumper pull.

[huntindog]

"....According to my calculation based on the CAT scales is there is about 600# more weight on the rear axle with the WDH engage oppose to not engage. Providing I'm interpreting this correctly:
With WDH ENGAGED based on CAT Scales:
Steer axle: 3520#
Drive Axle: 3560#
Trailer Axle: 6820#
Total Axle: 13900#
WITHOUT WDH engaged based on CAT Scales:
Steer axle: 3120#
Drive Axle: 4160#
Trailer Axle: 6660#
Total Axle: 13940#
..............................."

What is your Steer axle weight of the truck only, no trailer? You mentioned your front height within 1/8"; is that after WDH engaged and if so, 1/8 higher? You may be putting too much weight back onto the front axle (tends to bounce the rear more).

Your tires may contribute to the bounce if you have 17 or 18s, so I would air them all up to max cold before towing. If your tongue weight is right at 960lbs, adding passengers and other stuff in the truck will put you near your max payload. That is why I make the suggestion.

Last, if your tow vehicle is the 2018 in the signature, your shocks may be wore out. I used to tow a lot at max truck weight when I had a bumper pull.

That would be 600# LESS weight.

[Dana H]

What is your Steer axle weight of the truck only, no trailer?
You mentioned your front height within 1/8"; is that after WDH engaged and if so, 1/8 higher?
You may be putting too much weight back onto the front axle (tends to bounce the rear more).

Your tires may contribute to the bounce if you have 17 or 18s,
so I would air them all up to max cold before towing.
If your tongue weight is right at 960lbs, adding passengers and other stuff in the truck will put you near your max payload.
Last, if your tow vehicle is the 2018 in the signature, your shocks may be wore out.
[/QUOTE]

TAMRICK,
I don't have steer axle weight w/o trailer.
My front end is 1/8" higher so as I understand this should not be putting too much load towards the front. See attached report.
Truck has 20" wheel with a max air psi of 51psi. I typically run at 40# psi (as opposed to the 35# door sticker) but will test, till I upgrade my tires.
I agree my tires aren't helping and they are in the plan to upgrade when replaced. I don't consider this a safety problem but will upgrade in the future.
Tongue weight is typically loaded for a trip, on this particular trip I had more fresh water about 1/2 tank, typically I shoot for 1/3 of a tank with the black and gray water one empty.
This is the CAT Scale report numbers entered to this report using towingplanner.com/Calculators/TowingScaledWeights.

I only have 23000 miles on the truck and only about 7500 miles towing and don't think the shocks (RANCHO OFF ROAD) are causing any problems yet.

My plan will be to measure the gap between the axle and frame to see what clearance I can expect and factor that into my choice.

I'm still leaning towards the Sumo springs just not sure which ones Blue or Black, i definitely think the Yellows will be to stiff.

We probably be planning a short trip in the near future so I'll definitely try raising the tire pressures to 45# or 50# in truck tires and determine how that effects the bounce.

Again thanks to you and others with the help and experience in making my decision.