My Experience Towing with a '17 Suburban 5.3L

[tdebacker]

I know there are people who have talked about what they've towed, but I wanted to share my experience towing a fairly heavy trailer over a 7 hour trip.

Vehicle is a '17 Chevrolet Suburban Premier 4x4 with 91k on it. D
It does have magneride/air suspension and the Max Trailer Package. Only mods I have is a 2.5"/1.5" leveling kit and I upgraded to 10-PLY 33" tires. Nothing performance related.

Trailer in mention was a 20' x 83" tandem axle trailer hauling a 1982 Chevrolet K10 shortwide I bought off of my buddy. There was NO weight distribution hitch.

I stopped at a CAT scale and weighed myself at 13,860 pounds with 7780 lb pounds on the vehicle and 6040 lb on the trailer. I realized I had too much tongue weight, but went with it anyway.

Trip was from Casper, WY to Snowmass Village, CO, which is approximately 390 miles.

Air suspension kept it riding well and prevented it from sagging. Even with a high tongue weight, it kept it solid and didn't bounce uncontrollably.

On the downhills, tow/haul would automatically downshift to help hold on hills, and I used the trailer brakes. If I used the vehicle brakes on steep downhills, it would start to squirm a bit, so I kept with trailer brakes.

I haven't done the thermostat/pill flip thing other people have on these trans, but the trans fluid temp never got above 200° towing it. I was surprised.

Power...well it's a 5.3L. It comfortably pulled at 70 mph, but would struggle on the uphill, especially because the transmission didn't want to downshift enough to throw the revs up. I assume it was a safety thing since it doesn't do that normally.

I hand calculated the MPG and hovered between 9.8 MPG and 12.2 MPG depending on hills.

Overall, I wish it had more power and gears like a '18+ Denali, but I wouldn't hesitate to haul weight like that through the mountains again. It may have pulled it slow, but it pulled it safely and very controlled.

 

[swathdiver]

You can do a re-weigh by pulling forward or in your case backing up so that each axle is on a different scale, then you can subtract for the tongue weight.

 

[tdebacker]

You can do a re-weigh by pulling forward or in your case backing up so that each axle is on a different scale, then you can subtract for the tongue weight.

I don't think my axles are spaced enough to have separate axle weightings on the scale.

 

[swathdiver]

I don't think my axles are spaced enough to have separate axle weightings on the scale.

Ought to be, we do it all the time.

The steer axle scale is 15 feet, the drive axle scale is about 22 feet and the trailer axle scale is about 43 feet.

 

[gonatee]

I get flashed at night when im towing with the 2.5 levelling kit. Think the back magnaride spacer links need to be longer or shortened to bring the rear up a lil bot more...

 

[tdebacker]

I get flashed at night when im towing with the 2.5 levelling kit. Think the back magnaride spacer links need to be longer or shortened to bring the rear up a lil bot more...

I agree. I put new front assemblies when I installed the 2.5/1.5 leveling kit and I think the front sits higher now.

I'm thinking to put 2" rear blocks, maybe 2.5", and then build custom brackets for the ride height sensors.

 

[Larryjb]

Are you able to adjust the brake control unit? On my Techonsha I adjust it so that it applies the trailer brakes just before the TV brakes engage. This helps avoid any squirminess.

 

[tdebacker]

Are you able to adjust the brake control unit? On my Techonsha I adjust it so that it applies the trailer brakes just before the TV brakes engage. This helps avoid any squirminess.

Factory brake controller is proportional, so it applies as much pressure as you do, with the gain being how strong the maximum pressure is.

I don't think there's an option to set the trailer brakes first.

 

[Larryjb]

The Techonsha has a "boost" which I guess is equivalent to your gain control. Did you try increasing the gain slightly so that you would have more braking on the trailer than the truck?

Maybe it was just the way the Techonsha works (it is a proportional system too), but when I just touch the brakes I can feel the trailer pull slightly on the truck. I had no squirminess at all. However, the use of a WDH probably helped too by keeping more weight transferred to the front wheels.

 

[RobH]

I would speculate that your weights that are labeled on the weight ticket as

Steer Axle -- 7780 lbs
Drive Axle -- 6080 lbs
Trailer
Gross -- 13,860

are actually

Surburban -- 7780 lbs with both Suburban axles on the front pad
Trailer -- 6080 lbs with the trailer axles on the second pad where the Suburban rear axle should have been.

There is no way your Suburban could have weighed 13,860 pounds and the trailer nothing.

Visually, the Suburban front end is up in the air compared to the back end of the Surburban. It doesn't make sense that the rear axle weight was less than the front axle weight and the trailer weight was "0" as the weight ticket shows. That dual axle trailer probably weighs well over a ton empty. The people inside at the weight counter don't know how you are positioned on the three pads and whether your ticket makes sense.

I'm glad that you were able to make the trip successfully. But your rig was probably out of limits for tongue weight, total trailer weight, and possibly rear axle weight and tire ratings. With a load bearing hitch, the 2017 Suburban tow limits are 600 pound tongue weight and 5,000 pound trailer weight. See the attached 2017 GM Trailering Guide excerpts. Therefore, squirminess.

My Tahoe's axles are spaced so that I can put the forward axle on the forward weighing plate, the rear axle on the second weighing plate, and my travel trailer axle on the third weighing plate.

Here is a typical weight ticket for me.
Steer Axle -- 2520
Drive Axle -- 3477
Trailer -- 2820

As you can see, the total weight on the Tahoe's axles and tires is 5,997 pounds.

To get my trailer tongue weight,

1) I get a ticket with the three axles listed and compute the Tahoe weight with the trailer attached.
2) I pull off the scale and unhitch the trailer.
3) I get a second weighing of the Tahoe without the trailer.
4) The difference between the Tahoe weight with and without the trailer is the trailer tongue weight.

There are five weight limits

Front axle weight
Rear Axle weight
Suburban weight
Trailer total weight
Trailer tongue weight

The max Front axle and Rear axle weights will be on a sticker that looks like this one for my Tahoe, found on the driver's door opening.

They are identified as
GAWR FRT - Gross Axle Weight Rating Front
GAWR RR - Gross Axle Weight Rating Rear

The max trailer tongue weight with and without a weight distribution hitch are found in the Owner's Manual or the Trailering Guide. See page 13 of the attached GM 2017 Trailering Guide Excerpts. Not on the hitch. The hitch is probably manufactured to fit on Tahoes, Suburbans, one-half ton pickups with V6 engines, three quarter ton pickups, vans, etc. Maybe even a one-ton pickup. The hitch manufacturer does not know on what vehicle the hitch will be installed. That is why the sticker on the hitch says "Tow vehicle maximum trailer rating may be less."

FWIW and your weights may vary.

 

[tdebacker]

@RobH

My front end is in the air because I have a leveling kit and aftermarket struts that put the front end up higher than I expected, so when there's any weight, it squats a little bit.

I tried fitting each axle on each plate, but I couldn't seem to do that. I don't know if it was me or not, but I was having issues.

I'm aware the owners manual "states" not to tow heavy trailers above 5000 pounds without a WDH, but I'm not going to buy a WDH for one or two runs. I have the Max Tow Package so I am rated a maximum of 8000 pounds.

Most of the tongue weight issue was the fact I loaded the truck too far forward. Trailer weighs 2430 empty.

I knew I was overweight on the rear, but I opted for 10 ply tires on the Suburban when I got new ones, for instances like this. It kept steady even up and down the passes.

I know my trucks limits by the door stickers, 7500 lb GVWR and a 1506 lb payload.

I am aware of all of this.

In fact, I run my tires at 52 PSI because that is what the new tires would require proportionately to the axle weight ratings, although I'll bump them up to 55 psi with weight.

 

[swathdiver]

Are you able to adjust the brake control unit? On my Techonsha I adjust it so that it applies the trailer brakes just before the TV brakes engage. This helps avoid any squirminess.

We apply the gain setting by taking the vehicle and trailer up to 25 mph and using the manual apply lever to lock up the trailer brakes and then back it off some so it doesn't.

If we're towing at about 4,000 pounds we have the gain set to 4.5 and when the trailer is loaded to 7,000 pounds we set the gain to 7.0 so that the brakes on the trailer don't lock up if we have to stop fast.

 

[swathdiver]

I run my tires at 52 PSI because that is what the new tires would require proportionately to the axle weight ratings, although I'll bump them up to 55 psi with weight.

What Load Range E tires are you running?

The standard for LR E at 52 and 55 psi is 4,894 and 5,020 pounds per axle respectively. A nice margin but if left that way may wear the center of the tire down and cause them to bleed down more frequently. Maybe.

 

[tdebacker]

What Load Range E tires are you running?

The standard for LR E at 52 and 55 psi is 4,894 and 5,020 pounds per axle respectively. A nice margin but if left that way may wear the center of the tire down and cause them to bleed down more frequently. Maybe.

Load range 123, or 3145 lbs per tire from Nitto. If you do the math, 51 to 52 psi is what would equal out the load rating from factory. Thank god the tire light doesn't come on to tell me it's "too high".

I've put about 4000 miles on them and the wear is very consistent.

 

[swathdiver]

Load range 123, or 3145 lbs per tire from Nitto. If you do the math, 51 to 52 psi is what would equal out the load rating from factory. Thank god the tire light doesn't come on to tell me it's "too high".

I've put about 4000 miles on them and the wear is very consistent.

Load Range E 123 is 3,415 pounds @ 80 psi. What size wheel and tire are you running?

 

[tdebacker]

Load Range E 123 is 3,415 pounds @ 80 psi. What size wheel and tire are you running?

Factory 20" chrome plated wheels and 275/60R20 E.

Looks so much better than the 55r20s that come factory. If I end up keeping it long term, I want to regear to 3.73.

 

[swathdiver]

Factory 20" chrome plated wheels and 275/60R20 E.

Looks so much better than the 55r20s that come factory. If I end up keeping it long term, I want to regear to 3.73.

I made a little calculator that can extrapolate weights between posted pressures and set it up for your tire size and load range. Dual Tire Load Rating is not for a dually, it just means two tires on an axle. Fun stuff.