trailer surge

[joelger]

I have a 2011 Magic Tilt trailer with a GVWR of 9100 lbs. It has brand new axles, brakes, tires, brake lines and brake actuator/coupling. I have a 2011 SeaRay 250 SLX on it. According the boat specs, the standard weight for this boat is 5400lbs with the 350mag. I have the 8.2L so im adding 300 pounds for that. When i weigh the trailer/car and subtract the weight of the car after weighing it alone with the trailer un-attached the boat/trailer come in at 7500lbs. My tongue weight is 700lbs. I determined this by weighing the car and boat on a truck scale. The trailer wheels on one scale and the car on another. In that case i have 6740 for the car and 6800. With the trailer disconnected i have 6040 for the car.
My car (2022 escalade) has air suspension so when i connect the two it sits very level. The trailer corners are all within an inch of one another from the ground so im sure the weight on the axles is even. My tires are new.
When i drive the car it handles the pulling fine. When i am accelerating everything is fine as well. When i get up to 65+ MPH and begin to pull back on the acceleration or I am coasting the trailer feels as if it is pushing and pulling the car. There is no sway at all. I even tried steering slightly right to left to induce a sway and it was fine. It doesn't feel like a bounce but more as if the brakes are applying and releasing. To see if this was the case, i mechanically locked out the brakes by making a device that would not allow the brake actuator to compress. I still got the surging. ( the car had no problem stopping with no trailer brakes).
The car is rated for 700lbs tongue, 7700GTW and overall GVWR of 14000lbs. Clearly i am getting close but i feel like i should be ok. The diesel version of my car can handle 8200GTW so i feel like that number is based more on the pulling power of the are, not so much the suspension aspect. My tongue weight is slightly light of 9% but as i said earlier, no sway at all.
I considered tongue weight could still be the issue so i moved the boat slightly forward on the trailer which brought the tongue weight to almost 800 Lbs and it had no effect.
When i am pulling the trailer, it doesnt feel unsafe or as if i dont have control, it simply makes for a very uncomfortable ride. I take this boat from NY to Fla and the ride is important.
Any thoughts?

 

[alldodge]

I would guess the 700 tongue is a bit lighter.
To find true tongue weight at a scale, disconnect trailer on the scale and have tongue on one pad and rear wheels on another. The folks at the scale will wait for you to set it up. This way you get true weight of all 3 points (Truck/Tongue/Trailer wheels)

 

[joelger]

Thanks for the input. Even by increasing the tongue (using my method) it did the same thing. i also used the Curt OBD better weigh app and the weights for the tongue weight were all extremely close. I tried the weigh safe hitch which claims to be extremely accurate and it had a difference of a couple of hundred pounds. It is also my understanding that too little tongue will cause sway and this thing is pretty solid side to side.

 

[alldodge]

Guess I have nothing
It has independent suspension and magnetic dampening, so might just be sensors, but might be wrong also. Anyway to turn off the ride support temporarily

 

[briangcc]

Surge brakes on the trailer? You may just be trying to fight physics.

Let me explain...

As you let off on the gas on the tow vehicle, it slows down. Your trailer, not having the brakes engaged keeps going. Rule of physics - bodies in motion tend to stay in motion. Now since the vehicle is slowing down, you're compressing the surge coupler which applies the brakes on the trailer which if they are working are going to slow it down, possibly more than your tow vehicle. And you'll feel this back/forth going on as the two decelerate at different rates.

So long story short, this may just be normal given your particular tow setup.

Advice...try a different tow vehicle. Rent a pickup if needed. Uhaul, Budget, etc. See what happens without all the fancy stuff in your caddy kicking in. Very quick and cheap way to figure out what's at fault.

 

[Scott Danforth]

your escalade max towing capacity is about 7500# (depending on options)

independent rear suspensions suck for towing

auto-leveling suspension sucks for towing

auto-leveling independent suspsensions will fight the load

your boat dry weight may be 5580 for a 2011 250 SLX
Add the 75 gallons of fuel at 6.82#/gallon (512#)
Add the 80 gallons of fresh water at 8.34#/gallon (667#)
add teh 10 gallons of black water at 9#/gallon (90#)
add the 500# of gear like anchors, batteries, PDF's rope, etc
add the 2 coolers of beer at 120#

and your boat is up to 7470#

and then add your 1200-1400# trailer

your total towed weight is 8270-8470#

get a pickup truck with a live axle with a 9600# or higher towing capacity and try it. my guess the problem is your tow vehicle.

 

[joelger]

Guess I have nothing
It has independent suspension and magnetic dampening, so might just be sensors, but might be wrong also. Anyway to turn off the ride support temporarily

i cant seem to find a way to turn off the air suspension. It shuts off when the car is turned off so it can be jacked up safely but i cant seem to find a way to turn it off when driving

 

[alldodge]

Maybe ask dealer service department their opinion

 

[joelger]

your escalade max towing capacity is about 7500# (depending on options)

independent rear suspensions suck for towing

auto-leveling suspension sucks for towing

auto-leveling independent suspsensions will fight the load

your boat dry weight may be 5580 for a 2011 250 SLX
Add the 75 gallons of fuel at 6.82#/gallon (512#)
Add the 80 gallons of fresh water at 8.34#/gallon (667#)
add teh 10 gallons of black water at 9#/gallon (90#)
add the 500# of gear like anchors, batteries, PDF's rope, etc
add the 2 coolers of beer at 120#

and your boat is up to 7470#

and then add your 1200-1400# trailer

your total towed weight is 8270-8470#

get a pickup truck with a live axle with a 9600# or higher towing capacity and try it. my guess the problem is your tow vehicle.

I am aware that 5580 is the dry weight. All of the items you mention do add weight however the trailer/boat on a scale are still 7500lbs. Nothing else matters once it is on the scale other than the distribution. I am beginning to agree that the car is the problem and I guess the way to find out for sure is to use a different tow vehicle. I have a tundra which has the capacity but isn't ideal for 1200 mile drive. When i picked up the boat last spring i used the tundra to bring it back. I dont recall this happening but i also dont think i went much over 60 the whole way.
At this point i decided not to bring the boat to Fla this year. Once i get home i will try some of these suggestions.

 

[joelger]

Surge brakes on the trailer? You may just be trying to fight physics.

Let me explain...

As you let off on the gas on the tow vehicle, it slows down. Your trailer, not having the brakes engaged keeps going. Rule of physics - bodies in motion tend to stay in motion. Now since the vehicle is slowing down, you're compressing the surge coupler which applies the brakes on the trailer which if they are working are going to slow it down, possibly more than your tow vehicle. And you'll feel this back/forth going on as the two decelerate at different rates.

So long story short, this may just be normal given your particular tow setup.

Advice...try a different tow vehicle. Rent a pickup if needed. Uhaul, Budget, etc. See what happens without all the fancy stuff in your caddy kicking in. Very quick and cheap way to figure out what's at fault.

I am beginning to agree that the car is the problem and I guess the way to find out for sure is to use a different tow vehicle. I have a tundra which has the capacity but isn't ideal for 1200 mile drive. When i picked up the boat last spring i used the tundra to bring it back. I dont recall this happening but i also dont think i went much over 60 the whole way.

 

[joelger]

I have a 2011 Magic Tilt trailer with a GVWR of 9100 lbs. It has brand new axles, brakes, tires, brake lines and brake actuator/coupling. I have a 2011 SeaRay 250 SLX on it. According the boat specs, the standard weight for this boat is 5400lbs with the 350mag. I have the 8.2L so im adding 300 pounds for that. When i weigh the trailer/car and subtract the weight of the car after weighing it alone with the trailer un-attached the boat/trailer come in at 7500lbs. My tongue weight is 700lbs. I determined this by weighing the car and boat on a truck scale. The trailer wheels on one scale and the car on another. In that case i have 6740 for the car and 6800. With the trailer disconnected i have 6040 for the car.
My car (2022 escalade) has air suspension so when i connect the two it sits very level. The trailer corners are all within an inch of one another from the ground so im sure the weight on the axles is even. My tires are new.
When i drive the car it handles the pulling fine. When i am accelerating everything is fine as well. When i get up to 65+ MPH and begin to pull back on the acceleration or I am coasting the trailer feels as if it is pushing and pulling the car. There is no sway at all. I even tried steering slightly right to left to induce a sway and it was fine. It doesn't feel like a bounce but more as if the brakes are applying and releasing. To see if this was the case, i mechanically locked out the brakes by making a device that would not allow the brake actuator to compress. I still got the surging. ( the car had no problem stopping with no trailer brakes).
The car is rated for 700lbs tongue, 7700GTW and overall GVWR of 14000lbs. Clearly i am getting close but i feel like i should be ok. The diesel version of my car can handle 8200GTW so i feel like that number is based more on the pulling power of the are, not so much the suspension aspect. My tongue weight is slightly light of 9% but as i said earlier, no sway at all.
I considered tongue weight could still be the issue so i moved the boat slightly forward on the trailer which brought the tongue weight to almost 800 Lbs and it had no effect.
When i am pulling the trailer, it doesnt feel unsafe or as if i dont have control, it simply makes for a very uncomfortable ride. I take this boat from NY to Fla and the ride is important.
Any thoughts?

Any thoughts on if a weight distribution hitch might help with this?

 

[Scott Danforth]

I am aware that 5580 is the dry weight. All of the items you mention do add weight however the trailer/boat on a scale are still 7500lbs. Nothing else matters once it is on the scale other than the distribution. I am beginning to agree that the car is the problem and I guess the way to find out for sure is to use a different tow vehicle. I have a tundra which has the capacity but isn't ideal for 1200 mile drive. When i picked up the boat last spring i used the tundra to bring it back. I dont recall this happening but i also dont think i went much over 60 the whole way.
At this point i decided not to bring the boat to Fla this year. Once i get home i will try some of these suggestions.

I wouldnt trust the scale weight

 

[alldodge]

CAT scales are calibrated monthly and accurate to 0.2% (10K = +/- 20 lb)

 

[joelger]

I wouldnt trust the scale weight

I am using a truck stop scale on a major highway. Truckers use these scale and they are certified accurate.

 

[joelger]

Surge brakes on the trailer? You may just be trying to fight physics.

Let me explain...

As you let off on the gas on the tow vehicle, it slows down. Your trailer, not having the brakes engaged keeps going. Rule of physics - bodies in motion tend to stay in motion. Now since the vehicle is slowing down, you're compressing the surge coupler which applies the brakes on the trailer which if they are working are going to slow it down, possibly more than your tow vehicle. And you'll feel this back/forth going on as the two decelerate at different rates.

So long story short, this may just be normal given your particular tow setup.

Advice...try a different tow vehicle. Rent a pickup if needed. Uhaul, Budget, etc. See what happens without all the fancy stuff in your caddy kicking in. Very quick and cheap way to figure out what's at fault.

Thanks but as i put in my post, i made an appliance that i can simply drop on or off the trailer tongue which when in place will not allow the surge brakes to operate. It sits on the actuator between the pin for the damper and the steel surround for the coupler. it basically locks the actuator so it can not compress the cylinder. It did this just as a test. I get to the highway ramp, stop, put it in place and drive for a few miles to see if it has anything to do with the brakes. As soon as i get off the highway i can remove it so that the brakes are functional. i am certain that the brakes are not causing this because with this device i can actually look at the coupler/actuator using the trailer camera on the car and see that there is zero movement. i also disassembled the brake actuator and lubed up all of the rollers as well.

 

[Scott Danforth]

CAT scales are calibrated monthly and accurate to 0.2% (10K = +/- 20 lb)

I agree

I am using a truck stop scale on a major highway. Truckers use these scale and they are certified accurate.

however your weight you posted doesnt pass the smell test.

no way to get only 7500# with a 5580# dry weight (spec for 5.7 liter motor) and a 1200-1400# trailer unless you have no gear and empty fuel and water tanks.

 

[airshot]

In my towing experiences ( 60yrs) when your towing at maximum capacity and that capacity is high, the tow has never been overly pleasant. When the trailer is heavier than the tow vehicle, that extra weight can and will drive the tow vehicle some...

 

[froggy1150]

Does your ride control have a dedicated fuse you can pull

 

[bruceb58]

My boat has a 600# tongue weight. I have towed it with and without a WDH with a 2018 F-150 and it is a night and day difference towing it each way. I have electric over hydraulic brakes on my trailer so no concern with a surge brake actuator although the type hitch I use is compatible with surge brakes.

If you could somehow borrow someone's pickup and try towing with it, that might be a good test.

I use a Sherline scale to determine my tongue weight. I suggest buying one.

Amazon.com : sherline tongue weight scale

smile.amazon.com

 

[dingbat]

The short wheel base and the “centered” weigh distribution isn’t doing you any favors….

Towed for a number of years with a Tahoe with a heavy tow package. Load leveling etc. Towed my #4200 boat well…no complaints.

Got two footice.. jumped up to #5800. Still pulled and stopped well but the short wheel base and leveling system really struggled with 30’ of trailer on the bumper. Could fell everything..border line tail wagging the dog.

Tow with a F150 Crew Cab now. Day and night difference in how the truck handles the load.