Tire Pressure

[Ray LeTourneau]

All good and truthful replies here Alice. I'm guessing your Big Country came with LR "E" tires and the label on the side of the trailer indicates 80 psi. for your trailers gross weight. You can run the G614's at 80 psi but would be better off near 100 psi. At 80 psi they would probably run hotter which isn't good for tires. Heat is bad.
Porter Cable has a nice pancake compressor that is rated at 150psi. Probably available at Lowes.

 

[NWILSON]

Over inflation will lead to premature wear and loss of brake effectiveness by reducing the amount of tread contact on the pavement. If the sticker on the side of your rig lists tire pressure for 235/85R16 tires (the same as your G614s) then the vehicle manufacturer has determined the posted pressure to give optimum wear and braking performance for that size tire. Just because the sidewall on your car tire lists a higher maximum pressure you still use the figure on the sticker on the door frame don't you?

 

[Jim.Allison]

Dont take it personal, everyone is trying to help.

I know what she meant I have the same dang rims. Chill.

 

[Jim.Allison]

I thought their tires were new!!!!!

Hi Eric & Alice,

Here's the bad news - Goodyear says for RV tires:


Let's assume your trailer has a GVWR of 15,500 lbs and is fully loaded and close to that weight. Assuming your pin is carrying around 2,500 of that, the tires are carrying 13,000 lbs.

Goodyear's tire inflation tables show that for the G614 (235/85 R16), if you have 13,000 lbs evenly distributed across the tires, they would need a minimum of 90 psi to carry that load. Since RV weight is not distributed evenly, you certainly have one or more tires carrying more than their share and those loads would determine how much air pressure ALL tires need, because they should be inflated the same. So if one tire was carrying an extra 300 lbs, you'd need to inflate all tires to at least 100 psi. That heavy tire would be considered running flat if inflated to 80 psi because it's 20% underinflated.

Do you have tire damage? Maybe. Goodyear says you should have the tires inspected by a trained professional - presumably not the same guy who inflated them to 80 psi.

Internal damage doesn't necessarily show up right away. At some point in the future, long after you've forgotten all about this, a tire may suddenly fail.

Here's a link to the Goodyear information.

 

[Jim.Allison]

That sticker on the side of the big country is for the E rated ST tire. At 80 psi the G614 is rated less lbs load than the Towmax at 80 psi. The minimum pressure for a big country is going to be in the 100 to 110 psi cold pressure. Actually I would run them about 110 until I could weight the rig.

Over inflation will lead to premature wear and loss of brake effectiveness by reducing the amount of tread contact on the pavement. If the sticker on the side of your rig lists tire pressure for 235/85R16 tires (the same as your G614s) then the vehicle manufacturer has determined the posted pressure to give optimum wear and braking performance for that size tire. Just because the sidewall on your car tire lists a higher maximum pressure you still use the figure on the sticker on the door frame don't you?

 

[donr827]

Over inflation will lead to premature wear and loss of brake effectiveness by reducing the amount of tread contact on the pavement. If the sticker on the side of your rig lists tire pressure for 235/85R16 tires (the same as your G614s) then the vehicle manufacturer has determined the posted pressure to give optimum wear and braking performance for that size tire. Just because the sidewall on your car tire lists a higher maximum pressure you still use the figure on the sticker on the door frame don't you?

When I switched from E tires to the G614 on my previous trailer I took the CAT scale report with me to the Wingfoot dealer and he said that 100 pounds would be the pressure to use. Use the same on my current trailer and no problems........Don

 

[Jadatis]

You should calculate it whit my motorhome-tire-pressure-calculator, in wich I give not a minimum advice , but one with as much possible reserve that still has acceptable comfort and gripp.
so give the details of tires and vehicle , and I will make a picture of the filled in spreadsheet.
to give you an idea , here an example

 

[ericandalice]

Hi Eric & Alice,

Here's the bad news - Goodyear says for RV tires:


Let's assume your trailer has a GVWR of 15,500 lbs and is fully loaded and close to that weight. Assuming your pin is carrying around 2,500 of that, the tires are carrying 13,000 lbs.

Goodyear's tire inflation tables show that for the G614 (235/85 R16), if you have 13,000 lbs evenly distributed across the tires, they would need a minimum of 90 psi to carry that load. Since RV weight is not distributed evenly, you certainly have one or more tires carrying more than their share and those loads would determine how much air pressure ALL tires need, because they should be inflated the same. So if one tire was carrying an extra 300 lbs, you'd need to inflate all tires to at least 100 psi. That heavy tire would be considered running flat if inflated to 80 psi because it's 20% underinflated.

Do you have tire damage? Maybe. Goodyear says you should have the tires inspected by a trained professional - presumably not the same guy who inflated them to 80 psi.

Internal damage doesn't necessarily show up right away. At some point in the future, long after you've forgotten all about this, a tire may suddenly fail.

Here's a link to the Goodyear information.

Re: the damage.

They gave us the tires, we took them to her storage spot and put them on and then took her the mile down the road to our house and inflated to 109. Compressor couldn't go higher than that.

So I think we're good. Although we're in the market for a bigger, better compressor.

 

[Jim.Allison]

Here is a good onboard model if you have a generator or a large inverter. It will take your tires to 110 in a New York minute.


http://www.lowes.com/pd_57655-30449...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=

Re: the damage.

They gave us the tires, we took them to her storage spot and put them on and then took her the mile down the road to our house and inflated to 109. Compressor couldn't go higher than that.

So I think we're good. Although we're in the market for a bigger, better compressor.

 

[MCTalley]

Too late to the game for this thread, but in summary:

1. We have the same make, model and year trailer as you and, yes, the wheels are rated for 110 PSI.
2. We switched to G614's last spring and couldn't be happier.
3. We bought the exact same compressor linked to by Jim in the previous post and it tops off the tires to 110 PSI easily.
4. The Goodyear dealer where we bought our tires would not (per company policy) inflate them past 95 PSI (though I talked the tech into adding a little extra air before we hit the road - to around 100-102).
5. We also carry a Viair 12V 125 PSI pump but I haven't tried it out yet.
6. One mile at 80 PSI most likely didn't damage your tires at all.
7. Our tires now have 27,000 miles on them. Based on tread wear so far, looks like we will get about 60k miles out of them.

 

[Jim.Allison]

What is interesting is that the G614 intentionally has less tread so the tire will run cooler. Which is a big deal if you are running through Texas, New Mexico, Arizona, Nevada and California in the summer. I have heard a lot of people talk about tread depth, but it would be best practices on this tire to take a tread depth reading to see how much wear you have actually incurred, you may be surprised at how little you have actually incurred.

Too late to the game for this thread, but in summary:

1. We have the same make, model and year trailer as you and, yes, the wheels are rated for 110 PSI.
2. We switched to G614's last spring and couldn't be happier.
3. We bought the exact same compressor linked to by Jim in the previous post and it tops off the tires to 110 PSI easily.
4. The Goodyear dealer where we bought our tires would not (per company policy) inflate them past 95 PSI (though I talked the tech into adding a little extra air before we hit the road - to around 100-102).
5. We also carry a Viair 12V 125 PSI pump but I haven't tried it out yet.
6. One mile at 80 PSI most likely didn't damage your tires at all.
7. Our tires now have 27,000 miles on them. Based on tread wear so far, looks like we will get about 60k miles out of them.

 

[MCTalley]

What is interesting is that the G614 intentionally has less tread so the tire will run cooler. Which is a big deal if you are running through Texas, New Mexico, Arizona, Nevada and California in the summer. I have heard a lot of people talk about tread depth, but it would be best practices on this tire to take a tread depth reading to see how much wear you have actually incurred, you may be surprised at how little you have actually incurred.

Good point. We were just doing a visual seat of the pants comparison of my "on the ground" tires compared to my 0 mile spare hanging underneath the trailer. Might be interesting to take a depth measurement comparison.

 

[MCTalley]

What is interesting is that the G614 intentionally has less tread so the tire will run cooler. Which is a big deal if you are running through Texas, New Mexico, Arizona, Nevada and California in the summer. I have heard a lot of people talk about tread depth, but it would be best practices on this tire to take a tread depth reading to see how much wear you have actually incurred, you may be surprised at how little you have actually incurred.

You are right. I found a ruler with very small increments on it and found that I have about 9/32's to 10/32's tread remaining on my tires, out of 12/32's from the factory. Based on that, the tires are 20-30% worn (using 2/32s as 100% worn). That means I could possibly expect between 90,000 to 125,000 miles from them.

 

[TireHobby]

I’m a little late posting in this thread. I’m just going to post the way it’s supposed to be. I know some will disagree but what I print will be from tire industry standards.
The primary thing to remember when writing about tire pressures is they are set by the vehicle manufacturer, NOT the tire manufacturer. The recommended air pressures found on the vehicle certification label, tire placard and vehicle owner’s manual is for the Original Equipment (OE) tires.
The recommended tire pressure for the OE tires is your guide for setting air pressures for plus sized tires. Even those from other designs such as what has taken place with those in this thread. When designs are crossed the amount of load capacity the OE tires provide is the minimum acceptable load capacity needed from the replacement tires. So, if your OE tires were providing 3520# of load capacity with their recommended air pressure the new plus sized tires need to provide that much load capacity. In this situation the tire industry will never recommend less.
.
TireHobby

 

[asherwin]

One significant point not raised throughout all the earlier good comments is the need for the original valve stem on your rims to be replaced with a metal valve stem. This is necessary to safely accommodate the increased pressure.

 

[Gaffer]

It is important to weigh your loaded trailer. Only then can the tire manufacturers load chart be of use to determine if less than max tire pressure is okay.