2023 Chevy 3500 SRW - Suspension Upgrade

Jpalmer · 06-19-2023, 06:25 PM

I have a 2023 Chevy 3500 diesel HC CC SRW 4x4. I pull a 2022 HC 295rl approx. 11,600lbs. fifth wheel.

My brother has almost the same configuration but his is a Montana 3123 (12,600lbs) with a 2023 GMC Denali 2500 4x4 SRW and Timbrens on the rear of the truck.

When I hook up, the bed squats about 2 3/4". His, squats about 1". I am thinking about adding SumoSprings to both the truck and the trailer for stability.

I drove a 2001 Chevy Dually for 20+ years so the SRW is different.

Anyone added these to their truck or trailer or both? Worth it?

Thanks

**sourdough** · 06-19-2023, 06:46 PM

Quote:

Originally Posted by Jpalmer

I have a 2023 Chevy 3500 diesel HC CC SRW 4x4. I pull a 2022 HC 295rl approx. 11,600lbs. fifth wheel.

My brother has almost the same configuration but his is a Montana 3123 (12,600lbs) with a 2023 GMC Denali 2500 4x4 SRW and Timbrens on the rear of the truck.

When I hook up, the bed squats about 2 3/4". His, squats about 1". I am thinking about adding SumoSprings to both the truck and the trailer for stability.

I drove a 2001 Chevy Dually for 20+ years so the SRW is different.

Anyone added these to their truck or trailer or both? Worth it?

Thanks

Just for clarification the HC 295 has a gvw of 14,300 not 11,600. The 3123 has a gvw of approx. 16,400lbs. Your 3500 will safely carry your 295 in good fashion, his 2500 is overloaded.

Timbrens, Sumos, they are all just basically overload rubber springs. In the case if the 2500 and the 3123 all they do is fully compress and keep the springs from collapsing basically covering up the fact that the truck is overloaded. With the new ratings by GM I figure you're OK with payload since you didn't post those numbers.

Timbrens and Sumos (I prefer the progressive Sumos but that's JMO) soften up the ride and provide additional assistance in supporting a load. When they max out they just get fully compressed and act like a fully compressed overload spring...but not metal.

Your truck is probably fine with the load you have on it. If you wanted to level it out a bit you could use the Sumos to use that progressive spring nature to help the sag. You could also use air bags to do the same thing and have more control. I've read of complaints on both Timbrens and Sumos of harsh rides once the rubber springs were engaged and they compressed a bit.

Sumos on the trailer? I wouldn't as I don't see any benefit from it unless you are driving on off road trails or totally deteriorated highways. I think you have the Road Armor suspension, that should be good enough.

Jpalmer · 06-19-2023, 07:35 PM

Quote:

Originally Posted by sourdough

Just for clarification the HC 295 has a gvw of 14,300 not 11,600. The 3123 has a gvw of approx. 16,400lbs. Your 3500 will safely carry your 295 in good fashion, his 2500 is overloaded.

Timbrens, Sumos, they are all just basically overload rubber springs. In the case if the 2500 and the 3123 all they do is fully compress and keep the springs from collapsing basically covering up the fact that the truck is overloaded. With the new ratings by GM I figure you're OK with payload since you didn't post those numbers.

Timbrens and Sumos (I prefer the progressive Sumos but that's JMO) soften up the ride and provide additional assistance in supporting a load. When they max out they just get fully compressed and act like a fully compressed overload spring...but not metal.

Your truck is probably fine with the load you have on it. If you wanted to level it out a bit you could use the Sumos to use that progressive spring nature to help the sag. You could also use air bags to do the same thing and have more control. I've read of complaints on both Timbrens and Sumos of harsh rides once the rubber springs were engaged and they compressed a bit.

Sumos on the trailer? I wouldn't as I don't see any benefit from it unless you are driving on off road trails or totally deteriorated highways. I think you have the Road Armor suspension, that should be good enough.

Thanks, appreciate the feedback. I used the dry weight numbers on both trailers since we both just got the trailers and they are empty.. so we were just checking the squat. My truck curb weight empty is 8,391lbs, payload for the truck is 12,001 max, and I weighed it empty with me, the missus and the hitch for a grand total of 8,862lbs. trailer pin weight is 2400 lbs. but I added a combo washer dryer in the bathroom area so not sure of the hitched weight yet.

Once he takes his on a trip I will see what he says about his ride. I do want to level up a bit but do not want the harsh ride. Supposedly the Sumos are progressive. But I will look for feedback from those who have them. They aren't real pricey but I don't want to spend it if I don't have too.

**JRTJH** · 06-20-2023, 04:24 AM

Quote:

Originally Posted by Jpalmer

Thanks, appreciate the feedback. I used the dry weight numbers on both trailers since we both just got the trailers and they are empty.. so we were just checking the squat. My truck curb weight empty is 8,391lbs, payload for the truck is 12,001 max, and I weighed it empty with me, the missus and the hitch for a grand total of 8,862lbs. trailer pin weight is 2400 lbs. but I added a combo washer dryer in the bathroom area so not sure of the hitched weight yet.

Once he takes his on a trip I will see what he says about his ride. I do want to level up a bit but do not want the harsh ride. Supposedly the Sumos are progressive. But I will look for feedback from those who have them. They aren't real pricey but I don't want to spend it if I don't have too.

Just for clarification and to prevent confusion when someone responds to your post, the PAYLOAD for your truck is not 12001. That is the GVWR (Gross Vehicle Weight Rating). The PAYLOAD is posted on a yellow sticker on the driver's door pillar on your truck. If the truck CURB WEIGHT is 8391, then the PAYLOAD will be roughly 12001-8391=3610. Verify that by checking the payload sticker on YOUR TRUCK (not from a specifications chart on the Chevrolet website...

Your trailer pin weight (in the brochure and on Keystone's website) is calculated from ALL TRAILERS built of that model. It is NOT the actual weight of YOUR TRAILER. Why? Because any optional equipment, changes such as dining booth vs dining table, gas/electric refrigerator vs domestic refrigerator, SolarFlex 200 vs SolarFlex 400i and any other options that may be included or removed from what is in the brochure (which is unknown to you) and changes YOUR trailer pinweight from the ADVERTISED brochure pin weight.

As for the additional pin weight, it is calculated by Keystone with empty propane tanks, no battery bank, no fluids in any tank and with the water heater empty. ALL of those can dramatically change "YOUR trailer's pin weight" as will the addition of your washer/dryer.

I would urge you, the next time you hitch the trailer to your truck, to schedule a trip to the nearest CAT scale. Weigh your rig, front truck axle on pad #1, rear truck axle on pad #2 and trailer axles on pad #3. Then, drive off the scales, unhitch the trailer, return to the scales with the truck front axle on pad #1 and the rear axle on pad #2. With those two weights, you can calculate all that you "NEED TO KNOW" about your weights. Chances are very good that you are not overloaded, but depending on what you put in the trailer such as camping gear, clothing, tools, etc and what you put in the truck such as a generator, additional cargo, guests that might travel with you on a trip, or other items, you could very well be "approaching or over your payload.

The only way to know is to get accurate weights for your rig.

Hopefully this didn't come across as a "lecture" but rather as "clarification" of terms and "suggestions" for you to use. As for using payload and GVWR "with the wrong meaning" it will cause confusion when members tell you that your payload isn't 12,001 and don't explain what the terms really mean....

So, PAYLOAD, GVWR, RAWR,FAWR, GCWR AND MAX TRAILER RATING all have a specific meaning. Using the correct term helps prevent confusion when someone says one thing and you interpret it as something else.....

Anyway, get some accurate weights for your rig, then you'll know, not guess at what you're actually hitching behind your truck...

As for your brother with his 2500: He's very likely to be significantly overweight and could be damaging his truck or he could be putting himself and his financial security at risk if an accident might happen and someone's attorney starts digging into what he was driving and how it contributed to the accident. With today's computers in cars, all that information is contained in the vehicle databank in the truck's computer system. There's notes in every truck Owner's Manual detailing who has access to that data and when GM will release it to "third party requests".... We no longer are able to keep our information private. Big Brother is watching and has access to your truck's information....

notanlines · 06-20-2023, 04:38 AM

I’ve had Timbrens in the far past and air bags, never Sumos. Cost for the Sumos and Timbrens installed yourself range in the $300-350 area. I really think you’d be happier in the long run with a quality set of air bags with an on-board compressor. A now infamous individual once said “ the quality remains after the price is forgotten.”

Jpalmer · 06-20-2023, 04:36 PM

Quote:

Originally Posted by JRTJH

Just for clarification and to prevent confusion when someone responds to your post, the PAYLOAD for your truck is not 12001. That is the GVWR (Gross Vehicle Weight Rating). The PAYLOAD is posted on a yellow sticker on the driver's door pillar on your truck. If the truck CURB WEIGHT is 8391, then the PAYLOAD will be roughly 12001-8391=3610. Verify that by checking the payload sticker on YOUR TRUCK (not from a specifications chart on the Chevrolet website...

Your trailer pin weight (in the brochure and on Keystone's website) is calculated from ALL TRAILERS built of that model. It is NOT the actual weight of YOUR TRAILER. Why? Because any optional equipment, changes such as dining booth vs dining table, gas/electric refrigerator vs domestic refrigerator, SolarFlex 200 vs SolarFlex 400i and any other options that may be included or removed from what is in the brochure (which is unknown to you) and changes YOUR trailer pinweight from the ADVERTISED brochure pin weight.

As for the additional pin weight, it is calculated by Keystone with empty propane tanks, no battery bank, no fluids in any tank and with the water heater empty. ALL of those can dramatically change "YOUR trailer's pin weight" as will the addition of your washer/dryer.

I would urge you, the next time you hitch the trailer to your truck, to schedule a trip to the nearest CAT scale. Weigh your rig, front truck axle on pad #1, rear truck axle on pad #2 and trailer axles on pad #3. Then, drive off the scales, unhitch the trailer, return to the scales with the truck front axle on pad #1 and the rear axle on pad #2. With those two weights, you can calculate all that you "NEED TO KNOW" about your weights. Chances are very good that you are not overloaded, but depending on what you put in the trailer such as camping gear, clothing, tools, etc and what you put in the truck such as a generator, additional cargo, guests that might travel with you on a trip, or other items, you could very well be "approaching or over your payload.

The only way to know is to get accurate weights for your rig.

Hopefully this didn't come across as a "lecture" but rather as "clarification" of terms and "suggestions" for you to use. As for using payload and GVWR "with the wrong meaning" it will cause confusion when members tell you that your payload isn't 12,001 and don't explain what the terms really mean....

So, PAYLOAD, GVWR, RAWR,FAWR, GCWR AND MAX TRAILER RATING all have a specific meaning. Using the correct term helps prevent confusion when someone says one thing and you interpret it as something else.....

Anyway, get some accurate weights for your rig, then you'll know, not guess at what you're actually hitching behind your truck...

As for your brother with his 2500: He's very likely to be significantly overweight and could be damaging his truck or he could be putting himself and his financial security at risk if an accident might happen and someone's attorney starts digging into what he was driving and how it contributed to the accident. With today's computers in cars, all that information is contained in the vehicle databank in the truck's computer system. There's notes in every truck Owner's Manual detailing who has access to that data and when GM will release it to "third party requests".... We no longer are able to keep our information private. Big Brother is watching and has access to your truck's information....

Nah, didn't take it as a lecture, I prefer for someone to be straight with me, don't have to figure out what you were saying. All of those numbers came from the stickers on the truck and a Cat scale.

Good tip on the term payload, that was a new one to me, and being an IT guy, I dig what you are saying about big brother.

Alpine Custom Upgrade · 06-21-2023, 02:48 AM

Quote:

Originally Posted by Jpalmer

I have a 2023 Chevy 3500 diesel HC CC SRW 4x4. I pull a 2022 HC 295rl approx. 11,600lbs. fifth wheel.

My brother has almost the same configuration but his is a Montana 3123 (12,600lbs) with a 2023 GMC Denali 2500 4x4 SRW and Timbrens on the rear of the truck.

When I hook up, the bed squats about 2 3/4". His, squats about 1". I am thinking about adding SumoSprings to both the truck and the trailer for stability.

I drove a 2001 Chevy Dually for 20+ years so the SRW is different.

Anyone added these to their truck or trailer or both? Worth it?

Thanks

I added air bags to the rear suspension of two of my trucks to keep the truck level with a load on them. Also installed an on-board air compressor and switch to inflate and deflate. Works really well and no sag. I deflate them to 5 psi when not loaded and up to 125 psi when fully loaded. I would highly recommend that you consider this approach to solve the sag issue you are having.

jsb5717 · 06-21-2023, 07:30 AM

As John articulated, Payload is the key component in your first post and is too often not really, or properly, considered when people first start out. Timbrens, Sumos, Air Bags…all designed to help the ride but none of them increases your truck’s payload.

Personally, I prefer air bags with the on-board compressor. It gives you a lot of control while on the road for both leveling and smoothing the ride. That would work well on your truck.

Sadly, nothing will help your brother’s truck. He simply needs more truck. Use the yellow sticker and do the math. For pin weight, use either actual loaded (never empty) weight or calculated pin weight use 23% of GVWR. In your case that’s approx. 3300 lbs.

FWIW, calculated pin weight on your brothers trailer is approx 3750 lbs. I’m guessing that number is quite a bit higher than the posted payload capacity on the yellow sticker in his truck.

And remember, you’re not just hauling pin weight on your truck. It’s also hitch, people, and other gear. Add it all up when figuring how much payload capacity you need.

Jpalmer · 06-21-2023, 02:32 PM

Several recommendations for a "quality air bag system", any suggestions on a system?
Air lift
Firestone

?

jsb5717 · 06-21-2023, 03:28 PM

I think you’re fine with either one. I had Air Lift with Compressor on my last truck…worked well. Don’t really need it on the dually.

NMRandy · 06-21-2023, 03:52 PM

"As for your brother with his 2500: He's very likely to be significantly overweight and could be damaging his truck or he could be putting himself and his financial security at risk if an accident might happen and someone's attorney starts digging into what he was driving and how it contributed to the accident. With today's computers in cars, all that information is contained in the vehicle databank in the truck's computer system. There's notes in every truck Owner's Manual detailing who has access to that data and when GM will release it to "third party requests".... We no longer are able to keep our information private. Big Brother is watching and has access to your truck's information..."

A 2023 GM 2500 likely has an 11,500 GVW. If the truck weighs 8K, he would have 3500lbs of payload, so if he is overweight, it is not likely by much. As far a "damaging the truck", I seriously doubt it. AS far as being overweight, legally, maybe. The only difference between a 2500, and a 3500 GM diesel truck, is overload springs, and tires. The frame, drivetrain, and brakes are the same, 2500 or 3500. The 3500 needs to squat a little to get the truck to set down on the overload springs. It is made to do that, so it operates properly, so I wouldn't recommend air bags or sumo springs.

**sourdough** · 06-21-2023, 03:55 PM

Quote:

Originally Posted by NMRandy

"As for your brother with his 2500: He's very likely to be significantly overweight and could be damaging his truck or he could be putting himself and his financial security at risk if an accident might happen and someone's attorney starts digging into what he was driving and how it contributed to the accident. With today's computers in cars, all that information is contained in the vehicle databank in the truck's computer system. There's notes in every truck Owner's Manual detailing who has access to that data and when GM will release it to "third party requests".... We no longer are able to keep our information private. Big Brother is watching and has access to your truck's information..."

A 2023 GM 2500 likely has an 11,500 GVW. If the truck weighs 8K, he would have 3500lbs of payload, so if he is overweight, it is not likely by much. As far a "damaging the truck", I seriously doubt it. AS far as being overweight, legally, maybe. The only difference between a 2500, and a 3500 GM diesel truck, is overload springs, and tires. The frame, drivetrain, and brakes are the same, 2500 or 3500. The 3500 needs to squat a little to get the truck to set down on the overload springs. It is made to do that, so it operates properly, so I wouldn't recommend air bags or sumo springs.

The placard will tell the tale.

jsb5717 · 06-21-2023, 04:24 PM

Quote:

Originally Posted by NMRandy

A 2023 GM 2500 likely has an 11,500 GVW. If the truck weighs 8K, he would have 3500lbs of payload, so if he is overweight, it is not likely by much.

Except…there’s no need for guesswork and this isn’t how payload is determined. The OP’s truck sticker will tell him EXACTLY how much payload his truck is rated for. The need for timbrens or air bags is admittedly subjective but the starting point of usable payload isn’t.

notanlines · 06-21-2023, 04:24 PM

I’m suspecting a 2500 owner with hurt feelings? Eh, maybe not.

NMRandy · 06-22-2023, 06:06 AM

And a weight ticket from the CAT scale

Jpalmer · 06-22-2023, 05:46 PM

Placard:
Curb wt. 8,391
payload 3,709
GVWR 12,100
GCWR 29,700

Trailer weights:
Conventional trailer 20,000 tongue wt. 2,000
Gooseneck trailer 21,200 tongue wt. 2,100
Doesn't say anything about a fifth wheel unless the gooseneck spec is the same?

Interesting comment about "the truck has to squat a little to get to the overloads to work properly". Maybe my first trip this summer (about a 5 hour ride) will be a shakedown run and see how it does as is from the factory.

**JRTJH** · 06-22-2023, 06:38 PM

Quote:

Originally Posted by Jpalmer

Placard:
Curb wt. 8,391
payload 3,709
GVWR 12,100
GCWR 29,700

Trailer weights:
Conventional trailer 20,000 tongue wt. 2,000
Gooseneck trailer 21,200 tongue wt. 2,100
Doesn't say anything about a fifth wheel unless the gooseneck spec is the same?

Interesting comment about "the truck has to squat a little to get to the overloads to work properly". Maybe my first trip this summer (about a 5 hour ride) will be a shakedown run and see how it does as is from the factory.

I'm guessing these are specs/weights for your 1 ton truck, not your brother's 3/4 ton truck ?????

Some interesting "math facts" for you to consider. GM, Ford and RAM (as with the rest of the manufacturers) use some very "creative math" to come up with their towing specifications....

As an example, your truck has a GVWR of 12,100 pounds and a Max Trailer of 20,000 with a max GCWR of 29,700. Doing the math, if your truck is at GVWR (which is where it will be if you're towing a maximum load) then considering the GCWR, the maximum trailer you can tow is not 20K (29700-20000=9700 (just 1309 over your curb weight, even though the payload is 3709)... If your truck is at GVWR when you hitch a trailer (and it very likely will be close with a fifth wheel) then the maximum trailer, if you intend to stay under GCWR, is 29700-12100=17600, not the advertised 20000 pounds...

Then when you consider that the SAE J2801 towing standards are "tested" using a flatbed trailer with concrete weights (perfectly positioned to obtain 10% tongue weight), there is no "correlation to towing a RV" which has large sidewalls, much longer tongue to axle measurements and can NEVER be loaded to obtain a "perfect 10% tongue weight"....

So, the testing standards are "skewed to perfect towing conditions" not to "real world RV conditions"....

There's a lot of "creative advertising" from all manufacturers. Just using "a flatbed trailer to simulate an RV" is only one such "creativity". There's all sorts of "exclusions and exceptions" to much of the ratings and "maximums" on any specifications website.

So, do the math on YOUR TRUCK and TRAILER, don't just read a CAT scale sheet and compare it to the "ratings from GM"... Those ratings have conditions and exceptions hidden within them to make every manufacturer able to claim "best in class" in some category on all their charts......

rhagfo · 06-22-2023, 07:46 PM

Quote:

Originally Posted by Jpalmer

Placard:
Curb wt. 8,391
payload 3,709
GVWR 12,100
GCWR 29,700

Trailer weights:
Conventional trailer 20,000 tongue wt. 2,000
Gooseneck trailer 21,200 tongue wt. 2,100
Doesn't say anything about a fifth wheel unless the gooseneck spec is the same?

Interesting comment about "the truck has to squat a little to get to the overloads to work properly". Maybe my first trip this summer (about a 5 hour ride) will be a shakedown run and see how it does as is from the factory.

Quote:

Originally Posted by JRTJH

I'm guessing these are specs/weights for your 1 ton truck, not your brother's 3/4 ton truck ?????

Some interesting "math facts" for you to consider. GM, Ford and RAM (as with the rest of the manufacturers) use some very "creative math" to come up with their towing specifications....

As an example, your truck has a GVWR of 12,100 pounds and a Max Trailer of 20,000 with a max GCWR of 29,700. Doing the math, if your truck is at GVWR (which is where it will be if you're towing a maximum load) then considering the GCWR, the maximum trailer you can tow is not 20K (29700-20000=9700 (just 1309 over your curb weight, even though the payload is 3709)... If your truck is at GVWR when you hitch a trailer (and it very likely will be close with a fifth wheel) then the maximum trailer, if you intend to stay under GCWR, is 29700-12100=17600, not the advertised 20000 pounds...

Then when you consider that the SAE J2801 towing standards are "tested" using a flatbed trailer with concrete weights (perfectly positioned to obtain 10% tongue weight), there is no "correlation to towing a RV" which has large sidewalls, much longer tongue to axle measurements and can NEVER be loaded to obtain a "perfect 10% tongue weight"....

So, the testing standards are "skewed to perfect towing conditions" not to "real world RV conditions"....

There's a lot of "creative advertising" from all manufacturers. Just using "a flatbed trailer to simulate an RV" is only one such "creativity". There's all sorts of "exclusions and exceptions" to much of the ratings and "maximums" on any specifications website.

So, do the math on YOUR TRUCK and TRAILER, don't just read a CAT scale sheet and compare it to the "ratings from GM"... Those ratings have conditions and exceptions hidden within them to make every manufacturer able to claim "best in class" in some category on all their charts......

Well John what you failed to notice or mention is the pin weight number the OP stated. GM added more information to the stickers, now is that a suggest or max rating the 2,100# pin weight?
If GM is stating that as a maximum pin weight then there is an issue!

ON EDIT: payload should be payload 3,709 - 2,100 = 2,609# of unused payload if going by the hitch weight! Now in my opinion the OP should be able to use all of that 3,709# payload as long as they don’t exceed either axle rating.

**sourdough** · 06-22-2023, 08:08 PM

Quote:

Originally Posted by rhagfo

Well John what you failed to notice or mention is the pin weight number the OP stated. GM added more information to the stickers, now is that a suggest or max rating the 2,100# pin weight?
If GM is stating that as a maximum pin weight then there is an issue!

ON EDIT: payload should be payload 3,709 - 2,100 = 2,609# of unused payload if going by the hitch weight! Now in my opinion the OP should be able to use all of that 3,709# payload as long as they don’t exceed either axle rating.

Isn't that sort of like your vehicle showing a redline of 5500rpm but the little red line extends to 7000? BTDT...bad things happen.

rhagfo · 06-22-2023, 08:35 PM

Quote:

Originally Posted by sourdough

Isn't that sort of like your vehicle showing a redline of 5500rpm but the little red line extends to 7000? BTDT...bad things happen.

No more like a 7,000 rpm red line and the engine defuels at 3,500 rpm! There is nothing wrong running at or near max payload.

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