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Discussion Starter · #1 ·
Question about tire temperatures and PSI while towing - I have 10 ply/E rated (80psi) tires on my '13 and a 36' TT with a loaded tongue weight just shy of 1000 lbs. I have a 1200/12,000 lb Equalizer WDH and Firestone Ride Rite airbags. I keep the airbags at about 40lbs when connected to the trailer, which seems to take the sag out for the most part. I know the bags "undo" some of the leverage the WDH creates, so I'm thinking hard into it to make sure I'm set up just right.

Back in August I pulled the camper to the Michigan International Speedway from Iowa - about 8 hours - in 85ish degree ambient temps. I had the tires at 80lbs when we left. When we got home I checked the tire pressures right away and hit the sidewalls with an IR laser temp gauge.

Rear tires ~87 psi and 141 degrees.
Front tires ~82 psi and 119 degrees.

I was a little surprised at the psi/temp change in the rears. Are the numbers alarming to anyone?



**Airbags are not inflated in the pics
 

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It doesn't surprise me, when I took my CDL tests years ago the written tests addressed checking tire pressures when the tires were cold for this exact reason. I don't remember if it was in the CDL written information or somewhere else where it said don't adjust inflation pressures on hot tires.

I've even noticed a difference on tires that were on the sunny side of a trailer vs the shaded side of the trailer in the cold or hot months of the year. I would say keep watching them. I often use an IR temp gun to check trailer brakes and bearing temps. I figure if I have them all close in temperature after a trip then I probably have the bearings set right and the brakes aren't sticking. I have diagnosed bearings going out on various things by using the temp gun, it is very handy.
 

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Discussion Starter · #4 ·
Wouldn't worry me. How much does that trailer weigh?
I'm not too worried either since the tires are in great shape. I'm wondering if I need to adjust the WDH at all. I have a CAT scale nearby - I should probably roll her over to see if I'm distributing evenly.

Trailer probably weighs 8500
 

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Question? When you do fill the air bags, is it before or after you set the WD bars?

Seems like you are still pretty rear axle heavy, but without actual weights, it's still just a guess at best.. :)

Mitch
 

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Are those wheels rated for 80psi??? Stock F150 wheels aren't. Even the 7 lug HD versions if I recall correctly.
 

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Are those wheels rated for 80psi??? Stock F150 wheels aren't. Even the 7 lug HD versions if I recall correctly.
1. I recall a bunch of conjecture that they are not. I do not recall any real evidence posted on here, of what you state. I have never seen a single stock wheel stamp posted and certainly not from all the different wheel types (including the HD).

2. Why on earth would anyone drive an F150 at 80 PSI? beat to death, much
 

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OP The difference (assuming both tires were as stated front/rear) likely only shows that you have more weight, on the rears than fronts. I would only treat it as a possible problem because you don't seem sure that you are transferring enough weight. A trip to the scales (truck, truck/trailer not distributed & truck/trailer distributed) will prove that, if you chose to do it. High heat in tires could also just be because of an alignment problem. That could simply be changed because you are towing.
 

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My drivers are always warmer than my steers. My right side is also always warmer than the left, which I attribute to road crown. I temp check tires every trip.

80 psi in those tires will get you a load rating of 3860 lbs per tire, which is overkill. I would also worry about what psi your wheels (and valve stems) are rated for. I run 70 on my trailer and 45 on my truck, having seen my wheel and tire manufacturers inflation tables. Both my numbers are slightly higher than the yellow stickers recommend (65 and 35).
 

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Discussion Starter · #12 ·
Good info to consider here, but I’ve not heard of PSI ratings for wheels.? Also, I only run them up to 80 when towing. It’s way too rough of a ride when empty, so I run them at 50 front and 45 rear. (Although I did get damn near 20 mpgs on the interstate empty at 80 psi)

I’ve pulled the camper a short distance, including on the interstate at 65+, without inflating, and the truck had a washy feeling on the road. It wasn’t great. With 80 PSI, it’s really solid.

Much of what I read about 10 ply tires led me to believe I should air them up to tow - heat ruins tires, and sidewall crush builds heat.

I did take the truck over the scales last weekend after I adjusted the WDH for more leverage (raised the L-brackets on the trailer).

3460 front
4420 rear
7940 trailer

That seems decent to me. Thoughts? That’s with about 40psi in the airbags.
 

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If that's your axle weights with the WD bars set, you are probably over your rear axle GVW.. Here is my trucks ratings and note the trucks GVWR of #7700 as I have the Max Tow option too, but your rear axle weight would exceed my axle rating..



Of course, you are not going to implode the world with that rear weight.. You are getting down the road and in my old 97 F150 I exceeded the rear axle, GVWR by more than that, towing the same TT and did that for over 11 years... Right, wrong or whatever, it worked out and the world did not end..

Good luck!

Mitch
 
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Discussion Starter · #15 · (Edited)
What's your truck's GVWR and front/rear GAWRs?
Yep. Mine is the same other than my Axle Code is L9 instead of L6. Looks like you have the 3.73 rear end / towing, hauling limits still the same.

How would you manage that +300lbs on the rear axle? And it looks like I'm over the GVWR and GCVWR a bit too... I see some guys out there towing way more with a similar '13 F150 - saw a 5er at the campground with a '13 or '14 F150 last weekend. --at least im not over on the front axle weights, so I've got that going for me! My truck weighs about 7,000lbs without the trailer...

I'm seriously not wanting to upgrade to an F250 and I bought a 7,250 lbs camper to pull. (could have gone smaller, but all of us really liked this one) I knew it was big, but thought it was reasonable. I've got HD tires, upgraded shocks all around, and airbags - and it doesn't feel bad towing at all. In fact, it feels great! We put on almost 2,000 miles this summer and it feels really, really good. I usually stay around 65 on the interstate and I've always pulled equipment with common sense - It's a farm kid thing lol.

Would the average '17 or '18 F150 still be over on the weight ratings?

Damn
 

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You're a perfect candidate for an HDPP truck - unfortunately, you can't get an HDPP Platinum. It wouldn't bother me to pull it, but you need to realize that you're over in the rear and thus take it easy.

Those tires are also rated 3,860lbs. @ 80psi... so your inflation should be about right. But, again, realize that you're pretty close to the tire's maximum. That's why you're seeing high heat on those rears.
 

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"About" 7000 pounds? My '17 Supercab XLT weighed in at 4720 at the local landfill, empty. You need to weigh the rig at a local truck scale, as follows:

With a typical load for a camping trip, including water and propane....

1. Weigh the truck axles, one at a time, unhitched.

2. Measure the height of the ball with the trailer unhitched. Also measure the height at the front bumper.

3. Then hook up the trailer, and adjust the spring bars to bring the ball height back to the original position.

4. Adjust the airbags to bring the front bumper down to the original height.

5. Weigh each axle of the rig to make sure no ratings are exceeded. The trailer axles can be weighed together.

PS Overpressuring the tires (when cold) is a risk I would only take on the Auto-X course!

PPS those tires could get pretty hot just sitting in the sun... I've measured 170 on a black trailer wall.
 

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Discussion Starter · #18 ·
I suppose I should clarify, my truck weighs about 7000 pounds with my family, the pooch, and lightly/moderately loaded with some camping gear.
 

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Discussion Starter · #19 ·
I appreciate all the feedback here. It’s not like I started this post with the intention of going over every detail of my set up, but it sure helps me understand the dynamics and what is at play. My family is excited to have the camper and we’re talking about taking some longer road trips. I’ve even thought about adding sway bars to further stabilize everything. I’ve researched just about everything on my pick up, bumper-to-bumper, but this is one area I wasn’t 100% sure I had dialed in. Again, the feedback is appreciated!
 

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Tire pressures rise/fall approximately 1psi per 10 degress. This is why your tires "lose" air pressure when it gets cold outside. As long as the tire is not underinflated/overloaded, tire manufacturers cold inflation pressure ratings take into account pressure increases due to heat. Short answer - you're fine...
 
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