badabing

So, I've started trailering my cayman to the track this year. I've done my homework and have been optimizing the setup. I'm using a 2016 GMC Sierra 1500 with a Trailex CT-7541. I bought a tongue weight scale and a proper ball mount so my trailer is dead level when hooked up and all gear is loaded in the truck.

I'm fortunate to have a commercial scale nearby and I used it to make sure everything is ok and within weight capacities. Here's what the numbers look like;

Tow Vehicle only (fully fueled and with all gear and driver);

Front Axle 2,920 lbs
Rear Axle 2,440 lbs
Total Weight 5,400 lbs (I know there's a 40 lb discrepancy, they told me their scale is not certified for individual axle weight but for this purpose its close enough)

Trailer Only (Car fully fueled);
4,740 lbs

Combination Vehicle:

Total Rig 10,100 lbs
Front axle 2,580 lbs
Whole Truck Only 5,840 lbs
Trailer only 4,260 lbs

From these numbers, I deduce that the tongue weight is somewhere around 440 to 480 lbs. I also deduce that the weight on the rear axle of the truck is 3,260 lbs.

What confuses me is that when the trailer is connected, in addition to the tongue weight, it seems another 340 lbs is being shifted from the front axle to the rear axle. Am I interpreting these numbers correctly? Is this OK?

Scooby921

Unloaded your truck will sit higher in the rear. It's designed to ride somewhat level when loaded (standard for pickup truck design). Thus when you have the trailer on it and the truck sits perfectly level you are shifting a bit more weight toward the rear axle than what you measured with it unloaded. Nothing to worry about. Also, per GM's own standard you will want to bump up your tire pressures (on the truck) when towing. I don't know if they publish it in the owner's manual, but they do teach it during the trailer towing course for anyone doing trailer testing at the proving grounds. When adding trailer weight / load bump the tire pressures to max listed on the sidewall.

Cacciatore

To start, your total weight is well within GVWR of your tow vehicle so you are safe there. Measure the tongue weight with your scale and anything within 10% - 15% of the trailer weight is perfect.

I wouldn't expect 450 lbs on the tongue to squat the truck enough to shift another 340 lbs, but that could be just the individual axle measurement on the scale shifting some of the weight around.

badabing

Thanks for the replies. The scale doesn't do individual axles, so i got them by having the truck half on the scale and half off.

skxf430

The position of your car relative to your trailer axles can have a dramatic affect on your tongue weight. You may need to play around with where your car is positioned on your trailer to find the sweet spot.

badabing

Thanks. Thats exactly what I've done. I think I need to move the car even farther forward.

Dr911

OP

One other thing to be mindful of: once the weight is optimal (10-15% of total wt) point on the tongue scale, I take note of how the trailer is loaded.

After that I try to load the trailer the same way every time.

Because if the trailer is loaded differently, it has a significant impact: changes the tongue weight, and warrants rechecking w the TW scale.

Happy towing!
A

skxf430

Once, you have the proper position, I just put some blue painters tape on the floor which identifies the correction position of the car each time.

aryork

I have a GT4 and a small featherlite trailer. My tow vehicle is a buick enclave which is adequate (according to the specs), but barely. In practice, it tows fine however. I too bought a tongue weight scale because my weights were so close to the margins I needed to be somewhat sure of the numbers. Can't recall the ball-scale brand, but I used it for the first time last weekend. Its the type where you tighten an allen head on top of the ball until the scale reads 100 and back it off until the needle quits moving. When I put the trailer on the ball, I do not believe the loads - they are too small. If I go back to my old fashioned 400 lb capacity bathroom scale and do measurements, it all makes sense.

What is your tongue weight reading from the scale on the ball?

Also, in my situation the tongue weight is really low when the trailer is dead nuts level - like maybe 100 lb or less (with my car on it). You can move it up and down easily with your arm. Raising the ball a couple inches adds quite a bit of weight to the tongue in my case. I towed it home yesterday with lower tongue weight and it felt different - better, although I'm sure it was less than 10% of the total weight. The instability with low tongue weight is supposed to come into play (from what I have read) at higher speeds, maybe > 70 mph. I did not see any issues to up 70 yesterday.

I bought some aluminum tubing and have screwed it down to the bed to get a repeatable position. Again, I didn't want my numbers to be changing a lot since I am on the margin...

ExMB

With tape you won't see or feel. Go buy some double stick tape and a piece of 12" long 1" x 1" and glue it down. You know when you bump up to it.

LuigiVampa

On one of my open trailers I used to have a piece of two inch angle iron bolted to the deck so that it made a small pyramid. I could just roll into it and know I was on my sweetspot.

dan212

Unless I am misunderstanding what you are saying. 100 pounds when the trailer is "dead nuts level" sounds dangerously low.
Indeed, you don't want to overload your tow vehicle with too much tongue weight,
but a tongue weight of 100 would put you at risk of going to negative tongue weight as you go over bumps and the like.
If it goes negative, the only thing keeping things connected is the clamp on the trailer hitch.

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Steve Dawson

Sounds like you could raise the ball a lesser amount and then move the car forward a bit and end up with the desired tongue weight and a level trailer.