Good Sam Club Open Roads Forum: Looks like 30psi ought to be plenty good for towing
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 > Looks like 30psi ought to be plenty good for towing

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chrispitude

Allentown, PA

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Posted: 07/02/18 03:10pm Link  |  Quote  |  Print  |  Notify Moderator

1320Fastback wrote:

If your that close I think I'd change rims and tires to E rated.

Won't help with vehicle and suspension but might make a scary situation or blowout never happen.


I wanted to switch to load range LT-D tires, but all the LT tires in this size are super-knobby offroad tires. There wasn't a decent highway tire in the bunch.

So I went with the next load range down (P-XL), which is at least at the top of the P range. That led to me wanting to run a higher-than-sticker-minimum tire pressure, which resulted in this discussion thread. [emoticon]

lawrosa

Howell NJ

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Posted: 07/02/18 03:51pm Link  |  Quote  |  Print  |  Notify Moderator

chrispitude wrote:

DRTDEVL wrote:

You are overthinking this by a lot. You have another problem staring you in the face, yet you don't even realize it.

Your GVWR is 1313 lbs more than the curb weight of that Yukon XL. Your estimated tongue weight is 750 lbs, leaving you 563 lbs. If you put 30 gallons in the fuel tank, you are now down another 240 lbs, leaving only 323 lbs for all passengers and gear.


Yes, I don't like how close this is either.

It's two adults (400lbs), two kids (100lbs), two dogs (100lbs). We tow with the third-row bench removed, which is a heavy SOB, to reduce weight for this reason. So our 600lbs family minus the bench seat weight credit must be less than 563lbs. If that's true, it's just barely. We keep the trailer cargo as close as possible to the trailer axles, both to minimize angular momentum and the contribution to tongue weight.

I'm hoping my tongue weight is less than 750lbs, but only a trip to the scales will tell the full story.


When you go to the scales go by tour door tags axle weight.

Example. If scale weight has you at say 3800lbs rear subtract from your door tags 4000lb. That would leave you 200 lbs.

Dont worry so much about the GVW of the truck.

Use this calculator when you do the scales. makes it easy. you need 3 passes.


http://towingplanner.com/ActualWeights/TravelTrailerCatScales


Mike L ... N.J.

2006 Silverado ext cab long bed. 3:42 rear. LM7 5.3 motor. 300 hp 350 ft lbs torgue @ 4000 rpms
2018 coachmen Catalina sbx 261bh


JIMNLIN

Oklahoma

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Posted: 07/03/18 08:00am Link  |  Quote  |  Print  |  Notify Moderator

Tires on the back of a truck need proper air pressure to do two things.
1. ......carry the load without over heating at highway speeds.

2. and more air pressure to stop sway/handling issues....which means more psi to stiffen the sidewalls as a trailer can pushing the back of the tow vehicle around. P tires 44-51 psi is a very soft tire in the load carrying world of tires. I wouldn't run any P tire on the back of a truck carrying a load and pulling a trailer at anything less than max sidewall....especially those wide base /55-20" tires.

I've seen other 1/2 ton size vehicle owners go with those huge 20" E tires ....but come back in a few months and reported selling them and going with the std 17" OEM wheels and P265/70-17 tires.


"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides

chrispitude

Allentown, PA

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Posted: 07/12/18 12:21pm Link  |  Quote  |  Print  |  Notify Moderator

JIMNLIN wrote:

Tires on the back of a truck need proper air pressure to do two things.
1. ......carry the load without over heating at highway speeds.

2. and more air pressure to stop sway/handling issues....which means more psi to stiffen the sidewalls as a trailer can pushing the back of the tow vehicle around. P tires 44-51 psi is a very soft tire in the load carrying world of tires. I wouldn't run any P tire on the back of a truck carrying a load and pulling a trailer at anything less than max sidewall....especially those wide base /55-20" tires.

I've seen other 1/2 ton size vehicle owners go with those huge 20" E tires ....but come back in a few months and reported selling them and going with the std 17" OEM wheels and P265/70-17 tires.


I'm not sure I understand where you went with this. The P275/55R20 and P265/70R17 tire sizes differ in circumference by less than 1%. Tires can be characterized by (1) load rating and (2) sidewall flex; both sizes are rated for the load, and there is less sidewall flex in the P275/55R20 size. I started a thread to get advice on how much higher to go than the sticker minimum. Are we agreeing?

mkirsch

Rochester, NY

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Posted: 07/13/18 06:13am Link  |  Quote  |  Print  |  Notify Moderator

After all this discussion and tangential information, the simple answer is, you can go to maximum pressure as listed on the tire sidewall.

I would personally only do that if I felt some deficiency in the handling of the vehicle, or evidence of underinflation on the tires themselves.

Being a little overweight should not concern you, maybe a couple hundred pounds. Not a big deal, as long as you're under the tire weight ratings.


Putting 10-ply tires on half ton trucks since aught-four.

JIMNLIN

Oklahoma

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Posted: 07/13/18 07:37am Link  |  Quote  |  Print  |  Notify Moderator

Quote:

I started a thread to get advice on how much higher to go than the sticker minimum. Are we agreeing?

no we don't agree.
You've gotten pages of advise on best psi to run those rear P tires at.

chrispitude

Allentown, PA

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Posted: 07/13/18 08:02am Link  |  Quote  |  Print  |  Notify Moderator

mkirsch wrote:

After all this discussion and tangential information, the simple answer is, you can go to maximum pressure as listed on the tire sidewall.

I would personally only do that if I felt some deficiency in the handling of the vehicle, or evidence of underinflation on the tires themselves.


I think my plan is to try 40psi, 45psi, and 50psi on the back axle and see if I feel any difference. I'll also use my FLIR infrared gun to check temps across the tread. And of course, I'll report back here with my findings - and with IR pictures!

* This post was edited 07/13/18 09:45am by an administrator/moderator *

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