Advice on Tire Pressure

JSisemoreTX · 03-10-2021, 06:17 PM

I have a 2020 Keystone Avalanche 396BH. Dry weight around 14000 on 2 axles. About 16,000 going down highway with my F350 dually.

The tires are the original factory G rated tires...on a 2020 5th wheel...so I suspect the tires are 1-2 years old with less than 7,000 miles on them.

Dealership had tires to 80 psi and the max rating on these tires is 110....many people use the 100+psi for their heavy 5th wheels.

Anyone have a 16k lbs 5th wheel on 2 axles with these factory G rated tires? What is your ideal tire pressure (cold rating)?

Javi · 03-10-2021, 06:29 PM

110 psi cold

By the way there is a date code on each tire, you might be surprised at the age.

**sourdough** · 03-10-2021, 06:31 PM

At 16k 110 psi.

**chuckster57** · 03-10-2021, 06:50 PM

Quote:

Originally Posted by Javi

110 psi cold

By the way there is a date code on each tire, you might be surprised at the age.

Yup!! Last year after covid closures, I PDI’d a NEW trailer and found 3 year old tires.

ChuckS · 03-10-2021, 07:03 PM

I’ve been running 105 psi for the last five years on my current g rated tires..enter8mg sixth season of use .

The dealership did you wrong running 80 psi on those 14 ply tires

JSisemoreTX · 03-10-2021, 08:23 PM

Thx all...yes I am also aware that manufacture date of tire is not the same as Manufacture date of 5th wheel.....

I am more concerned with the appropriate tire pressure for this post.

Ken / Claudia · 03-10-2021, 10:15 PM

Date code and knowing what that number is very important. As much or more so than PSI. PSI is easy use what is printed on the door sticker, or the tire. They wear out by age before the tread is gone.

CWtheMan · 03-11-2021, 02:41 AM

There are three places to find the correct cold inflation pressures for original equipment tires.

1. Vehicle certification label.
2. Tire load and inflation placard.
3. Vehicle owners manual.

Anyone that takes you down a path that leads to less cold inflation pressures than provided in those references is leading you down an unsafe path.

xrated · 03-11-2021, 03:39 AM

Quote:

Originally Posted by JSisemoreTX

I have a 2020 Keystone Avalanche 396BH. Dry weight around 14000 on 2 axles. About 16,000 going down highway with my F350 dually.

The tires are the original factory G rated tires...on a 2020 5th wheel...so I suspect the tires are 1-2 years old with less than 7,000 miles on them.

Dealership had tires to 80 psi and the max rating on these tires is 110....many people use the 100+psi for their heavy 5th wheels.

Anyone have a 16k lbs 5th wheel on 2 axles with these factory G rated tires? What is your ideal tire pressure (cold rating)?

And something else to just think about here. Don't be confused by what "heavier 5th wheelers" are doing. Here is an example of possibilities....your trailer vs. mine, which is a "heavy 5th wheeler".

Your trailer at 16,000 lbs going down the road, and assuming at least 20% of that weight is on the pin of the truck....so the tires (4 of them) are carrying a combined weight of 12,800 lbs. So divided by 4, each tire is at 3200 lbs....and that is assuming that the trailer weight is divided perfectly for each tire (it never is...but for this example that's what we'll say).

My trailer at 20,000 lbs going down the road and assuming at least 20% of that weight is on the pin of the truck...so the tires (6 of them) are carrying a combined weight of 16,000 lbs. So divided by 6, each tire is at 2666 lbs....and that is assuming that the trailer weight is divided perfectly for each tire....and we know it never is.....except in an example like this.

This example above ^^^^ also assumes the very same load range "G" tire...so my point here is that don't be fooled by "heavier 5th Wheelers" and tire pressure. The dealer that had you inflated to 80 psi was dead wrong.

And BTW.....my normal cold tire pressure.....110 psi on all six trailer tires. At that pressure, the tires...when new will have a load rating capacity of 4080 lbs each...times 6 = 24,480 lbs. With only 16,000 lbs on them (20,000 lbs minus my 4000 lbs of pin weight), that is an "excess" of 8480 lbs...or roughly 1400 lbs/per tire

CWtheMan · 03-11-2021, 04:08 AM

Just to clear-up the trailer weight thing.

ALL Original Equipment tires are selected to support the vehicle certified GAWRs. (Ref; FMVSS 571.120

ALL after market selections MUST have a load capacity equal to or greater than what the OE tires provided at vehicle manufacturer recommended cold inflation pressures. (Ref; https://www.maxxis.com/warranty/trailer-warranty ) Just about any tire warranty is going to mention the industry standard for replacement tires. Here I've used Maxxis because it's respected and a RV trailer tire builder.

xrated · 03-11-2021, 04:21 AM

Quote:

Originally Posted by CWtheMan

Just to clear-up the trailer weight thing.

ALL Original Equipment tires are selected to support the vehicle certified GAWRs. (Ref; FMVSS 571.120

ALL after market selections MUST have a load capacity equal to or greater than what the OE tires provided at vehicle manufacturer recommended cold inflation pressures. (Ref; https://www.maxxis.com/warranty/trailer-warranty ) Just about any tire warranty is going to mention the industry standard for replacement tires. Here I've used Maxxis because it's respected and a RV trailer tire builder.

Looks like I'm covered nicely.....tire load capacity = 24,480. GAWR = 21,000 lbs!

CWtheMan · 03-11-2021, 04:41 AM

Quote:

Originally Posted by xrated

Looks like I'm covered nicely.....tire load capacity = 24,480. GAWR = 21,000 lbs!

Yup!

A side note; all of the major ST tire providers are now building the ST215/75R17.5 with a LRH. The heavy dual axle trailers will soon need them.

xrated · 03-11-2021, 05:38 AM

Quote:

Originally Posted by CWtheMan

Yup!

A side note; all of the major ST tire providers are now building the ST215/75R17.5 with a LRH. The heavy dual axle trailers will soon need them.

Just a note to you CW....I really enjoy you sharing your knowledge..and more importantly...FACTS, as it relates to tires in general and RVs specifically. I've learned a lot from you and others over the short 4 1/2 years that I've been on this forum and I just wanted to let you know I appreciate ya'

JSisemoreTX · 03-11-2021, 06:53 AM

Quote:

Originally Posted by xrated

Just a note to you CW....I really enjoy you sharing your knowledge..and more importantly...FACTS, as it relates to tires in general and RVs specifically. I've learned a lot from you and others over the short 4 1/2 years that I've been on this forum and I just wanted to let you know I appreciate ya'

Agreed! Thanks CW!

travelin texans · 03-11-2021, 08:20 AM

Quote:

Originally Posted by CWtheMan

There are three places to find the correct cold inflation pressures for original equipment tires.

1. Vehicle certification label.
2. Tire load and inflation placard.
3. Vehicle owners manual.

Anyone that takes you down a path that leads to less cold inflation pressures than provided in those references is leading you down an unsafe path.

#4 molded into the sidewall of the tire.
This is the pressure I use, be it right/wrong & always have on RVs.

**JRTJH** · 03-11-2021, 08:39 AM

Quote:

Originally Posted by JSisemoreTX

I have a 2020 Keystone Avalanche 396BH. Dry weight around 14000 on 2 axles. About 16,000 going down highway with my F350 dually.

The tires are the original factory G rated tires...on a 2020 5th wheel...so I suspect the tires are 1-2 years old with less than 7,000 miles on them.

Dealership had tires to 80 psi and the max rating on these tires is 110....many people use the 100+psi for their heavy 5th wheels.

Anyone have a 16k lbs 5th wheel on 2 axles with these factory G rated tires? What is your ideal tire pressure (cold rating)?

There is a "noteworthy placard" located on the front roadside corner of your RV. It will list the GVWR, GAWR, TIRE SIZE and RECOMMENDED PRESSURE....

I'd ask, what does that placard say is the recommended tire pressure??? It was put there by the manufacturer who designed, engineered, built and certified your trailer.... (but what would they know?)...

Three (not one) very important factors to consider. First is tire age, found molded into the sidewall of every tire, displayed as a 4 digit number, first two are the week of manufacture and the second two are the year of manufacture. That date is probably the single most important information found on an individual tire. Second is the maximum inflation pressure/load rating. Third is the tire size.

All three are vital in the decision making process. Any one that doesn't fall into the "serviceable tire" decision making should cause the tire to be considered unserviceable until fixed. Skip or omit any one and you're potentially "doomed" to tire failure......

CWtheMan · 03-11-2021, 10:46 AM

Quote:

Originally Posted by travelin texans

#4 molded into the sidewall of the tire.
This is the pressure I use, be it right/wrong & always have on RVs.

The most accurate definition for the tire's sidewall cold inflation pressure is; it's the tire manufacturers maximum permissible cold inflation pressure needed for the tire to produce it's maximum load capacity.

dutchmensport · 03-11-2021, 11:09 AM

Wow! You all confused me here! Too many numbers.

xrated · 03-11-2021, 12:56 PM

Quote:

Originally Posted by dutchmensport

Wow! You all confused me here! Too many numbers.

What are you confused about.........or was that just a funny remark. I'm not sure since there wasn't a smiley after your comment.

gearhead · 03-11-2021, 02:13 PM

Quote:

Originally Posted by CWtheMan

Yup!

A side note; all of the major ST tire providers are now building the ST215/75R17.5 with a LRH. The heavy dual axle trailers will soon need them.

I really thought I wanted the advantages of the H rated tires when I was shopping for another 5th. Now that I have them, I think I would prefer triple axles with 16's. Those 17.5 tires and wheels are heavy, very heavy.

Hey Sisemore..are the crappie biting in Luce's Bayou?
Not that I have time to chase them, leaving in 10 days for hillbilly country...Tennessee, N Carolina, and Virginia.

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