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Old 07-02-2022, 07:18 AM   #1
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Air pressure

After realizing that the driver's side rear inside tire was inflated to 35PSI from the factory, I wanted to ask fellow owners what PSI do you have your tires inflated to?

I checked all the other tires, and I'm sitting at 105-108PSI - I have a 2021.5 GT7 36K7.
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Old 07-02-2022, 07:28 AM   #2
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There are literally hundreds if not thousands of posts on this forum of the correct tire pressure. Spend a couple of minuets searching and you will find much more info that you need.
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Old 07-02-2022, 07:35 AM   #3
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While I appreciate your response (which doesn't provide much resolution to the question), this is exactly why I posted this in the Georgetown thread because there are literally hundreds, if not thousands of posts on tire pressure. Each one has different makes/models, chassis, and pressures - some even with different pressures for the same rig.

I am asking reliable folks such as NXR and Cdefrees and others that have similar/identical rigs and could chime in with info that could help a very narrow field of owners - 2020 and up Georgetown GT series 5/7.

I'm pretty sure there are a lot of variables that would be considered that could help owners by having this post exactly where it is.
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Old 07-02-2022, 08:46 AM   #4
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Quote:
Originally Posted by leonidas
After realizing that the driver's side rear inside tire was inflated to 35PSI from the factory, I wanted to ask fellow owners what PSI do you have your tires inflated to?

I checked all the other tires, and I'm sitting at 105-108PSI - I have a 2021.5 GT7 36K7.
You likely have a big problem with that 35 PSI tire. A tire that is inflated to 80% or less of the minimum pressure required to support the actual weight on the tire is considered flat. If it was that low for any length of time and especially if it was driven on for any distance that tire should be considered to be irreparably damaged.

The Michelin XRV 235/80R22.5 inflation chart, the tire usually used on the Georgetowns, only goes down to 70 PSI and that means the tire should never intentionally be set to lower than 70.

What tires and tire size are on your GT7?

Motorhomes have two tires on each side on the rear because they need two tires to safely carry the weight. When one tire of a rear dual pair is very low the weight carried by that tire is shifted to the other tire on that side. That grossly overloads the other tire, far beyond its design limits.

That other tire is now literally a time bomb even though it probably shows zero evidence of damage externally. It can fail prematurely in days, weeks or months; there's no way to know when for sure.

Do you have any idea how long you drove on that 35 PSI tire?

As for the pressures, if you have never had the coach weighed when fully loaded up for a long trip with everyone and everything, the best place to start is with the pressures listed on the sticker on the wall behind the driver.

By federal law, the pressures listed on that sticker must show the MINIMUM pressure required to fully support each axle's maximum design weight, its Gross Axle Weight Rating or GAWR. Many later model Georgetowns, depending on the exact model, seem to have 90 PSI or 95 PSI on that sticker.

What does your sticker show?

Hopefully you complained to the dealer as soon as you found that flat tire AND you have repeatedly rechecked that tire to assure it is not losing air.

Otherwise you are staring at paying the cost yourself to replace both of those tires on that side in order to avoid one coming apart and causing many thousands of dollars of damage in addition to the inconvenience problems. Even if you did complain to the dealer immediately it will be a major fight to get them to pay for two new tires and the replacement cost.

What just happened to you is why the use of an aftermarket Tire Pressure Monitoring System or TPMS is highly recommended for any RV and anything being towed. The TPMS display up front gives you a readout of each tire's pressure and sounds an alarm as the pressure drops below whatever limit you have set. I use the TST 507 with ten cap sensors, six for the motorhome and four for the toad.

https://www.technorv.com/tst-507-tpm...-and-repeater/

Did you check the tire pressures after the motorhome had not been driven on for several hours and before any direct sun hit them? A pressure check usually is done in the morning to assure the tires are at the ambient temperature. I'm asking because the pressures you listed of 105 - 108 PSI can be normal if the tires were still warm from being driven on.

BTW, I highly doubt the tires came from the factory with those pressures. Forest River does a front end alignment on all new Georgetowns before they leave the factory and the first step on any alignment is to assure the tire pressures are correct.

If you did check the pressures with the tires cold, those high pressures sound more like a clueless dealer technician.

That low tire sounds like a leaker, maybe a leaking valve stem extension. A leaking or loose valve extension is not uncommon on the inside dual.

Sorry for the bad news,

Ray
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Old 07-02-2022, 08:46 AM   #5
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Setting tire pressures on any RV is not rocket science. As long as you are between what your coach sticker says and the max cold psi on the tire, you are good. If you want to be precise, weigh your coach and use tire pressure tables.
If you just want confirmation from other owners of similar coaches, great, but how they load and travel may not be identical to yours.
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Old 07-02-2022, 08:57 AM   #6
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Quote:
Originally Posted by NXR View Post
You likely have a big problem with that 35 PSI tire. A tire that is inflated to 80% or less of the minimum pressure required to support the actual weight on the tire is considered flat. If it was that low for any length of time and especially if it was driven on for any distance that tire should be considered to be irreparably damaged.

The Michelin XRV 235/80R22.5 inflation chart, the tire usually used on the Georgetowns, only goes down to 70 PSI and that means the tire should never intentionally be set to lower than 70.

What tires and tire size are on your GT7?

Motorhomes have two tires on each side on the rear because they need two tires to safely carry the weight. When one tire of a rear dual pair is very low the weight carried by that tire is shifted to the other tire on that side. That grossly overloads the other tire, far beyond its design limits.

That other tire is now literally a time bomb even though it probably shows zero evidence of damage externally. It can fail prematurely in days, weeks or months; there's no way to know when for sure.

Do you have any idea how long you drove on that 35 PSI tire?

As for the pressures, if you have never had the coach weighed when fully loaded up for a long trip with everyone and everything, the best place to start is with the pressures listed on the sticker on the wall behind the driver.

By federal law, the pressures listed on that sticker must show the MINIMUM pressure required to fully support each axle's maximum design weight, its Gross Axle Weight Rating or GAWR. Many later model Georgetowns, depending on the exact model, seem to have 90 PSI or 95 PSI on that sticker.

What does your sticker show?

Hopefully you complained to the dealer as soon as you found that flat tire AND you have repeatedly rechecked that tire to assure it is not losing air.

Otherwise you are staring at paying the cost yourself to replace both of those tires on that side in order to avoid one coming apart and causing many thousands of dollars of damage in addition to the inconvenience problems. Even if you did complain to the dealer immediately it will be a major fight to get them to pay for two new tires and the replacement cost.

What just happened to you is why the use of an aftermarket Tire Pressure Monitoring System or TPMS is highly recommended for any RV and anything being towed. The TPMS display up front gives you a readout of each tire's pressure and sounds an alarm as the pressure drops below whatever limit you have set. I use the TST 507 with ten cap sensors, six for the motorhome and four for the toad.

https://www.technorv.com/tst-507-tpm...-and-repeater/

Did you check the tire pressures after the motorhome had not been driven on for several hours and before any direct sun hit them? A pressure check usually is done in the morning to assure the tires are at the ambient temperature. I'm asking because the pressures you listed of 105 - 108 PSI can be normal if the tires were still warm from being driven on.

BTW, I highly doubt the tires came from the factory with those pressures. Forest River does a front end alignment on all new Georgetowns before they leave the factory and the first step on any alignment is to assure the tire pressures are correct.

If you did check the pressures with the tires cold, those high pressures sound more like a clueless dealer technician.

That low tire sounds like a leaker, maybe a leaking valve stem extension. A leaking or loose valve extension is not uncommon on the inside dual.

Sorry for the bad news,

Ray
NXR, seriously... I need to Venmo you some money for how much you've helped me this past year. Thank you!

I'll post the specifics for the questions you asked and I know for certain this will help owners both current and future of the GT series rig. This isn't the first instance of the dealership having a brand new employee inflate a tire to passenger car pressure.

Also, the plastic lug nut covers have been flying off one by one this past week. We are down to 5 casualties so far... how are yours doing?
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Old 07-02-2022, 09:06 AM   #7
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Quote:
Originally Posted by NMWildcat View Post
Setting tire pressures on any RV is not rocket science. As long as you are between what your coach sticker says and the max cold psi on the tire, you are good. If you want to be precise, weigh your coach and use tire pressure tables.
If you just want confirmation from other owners of similar coaches, great, but how they load and travel may not be identical to yours.
I completely understand that - this is precisely why I don't ask questions like: where is the valve stem for the inner tire, where can I find the maximum pressure for my tire, and/or how can I tell if the tread is too low. My question was very specific to what are other GT5/7 owners inflating their tires to regarding PSI. What alarmed me was the inner tire being 35 PSI with no known leaks or issues and beginning to question what should not be rocket science.

But - in keeping with the newly established forum post requirement, I guess this would be an acceptable question:

What would be the rocket projections within a 3-dimensional space?

I would think that if you are asking about the directions of the forces, then weight acts vertically downwards, thrust will usually act along a tangent to the rocket's direction of travel (although some rockets can vary the direction of thrust to achieve a limited amount of steering) and drag will act in the opposite direction to thrust. A rocket is not designed to generate lift, so lift forces on a rocket will be insignificant compared to the other forces involved.

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Old 07-02-2022, 09:41 AM   #8
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It's not that hard.

All road-going vehicles have a data plate in the driver's door jam (or driver's side of a trailer) showing the required tire pressure to support the gross vehicle weight rating -- the maximum legally allowed weight of the vehicle. It's not a matter of opinion or poll.

Never inflate to less pressure. Over-inflation does not increase load capacity as the tires are just one part of the suspension.

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Old 07-02-2022, 10:08 AM   #9
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Originally Posted by Chuck_S View Post
It's not that hard.

All road-going vehicles have a data plate in the driver's door jam (or driver's side of a trailer) showing the required tire pressure to support the gross vehicle weight rating -- the maximum legally allowed weight of the vehicle. It's not a matter of opinion or poll.

Never inflate to less pressure. Over-inflation does not increase load capacity as the tires are just one part of the suspension.

-- Chuck
Thanks Chuck! All the information is all helpful, and I appreciate it. Perhaps I should have added more context to my original question because there may have been some confusion.

The PSI question was more geared towards folks with a similar rig as mine and also the variabilities in the last few years (V10 vs V8, different suspensions and stabilizers, full load, etc). I know a few folks that have 2021 GT7 and have much different insight because they drive a V10 with different shocks and older style stabilizers. Some have the Koni upgrades and Sumo springs.

My question was more about variabilities in PSI and perhaps some ideas to think about that may help determine if I am completely insane by keeping mine around 105 if there is a much better way/method.

Also, sorry NMWildcat... I didn't mean to come off as snarky; I was just getting frustrated with some of the responses as I am not as nieve as some may think when it comes to mechanics and technology. I do appreciate your input, and you actually provided some very sound advice. Thank you.
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Old 07-02-2022, 12:24 PM   #10
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If the placard specifies 105psi I'd run 105psi. But I have the naive opinion that the engineers who designed these know more than random guys on the internet.

The placard only applies to the tires listed on it though so there's room for expert opinion if something else is on the wheels.

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Old 07-02-2022, 02:31 PM   #11
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Oh my

Quote:
Originally Posted by leonidas View Post
After realizing that the driver's side rear inside tire was inflated to 35PSI from the factory, I wanted to ask fellow owners what PSI do you have your tires inflated to?

I checked all the other tires, and I'm sitting at 105-108PSI - I have a 2021.5 GT7 36K7.
So you have a coach a year to year and a half old and you just now want to know if the recommended tire pressure is real or some fake number they are tricking you with? Sorry but the lengths this country has fallen to sure makes it look like the future is not to bright. Oh Iím sorry but the 105 psi is Not fake news - no matter how you spin it. Please be careful as me thinks driving is a Big challenge to you.
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Old 07-02-2022, 02:39 PM   #12
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So you have a coach a year to year and a half old and you just now want to know if the recommended tire pressure is real or some fake number they are tricking you with? Sorry but the lengths this country has fallen to sure makes it look like the future is not to bright. Oh I’m sorry but the 105 psi is Not fake news - no matter how you spin it. Please be careful as me thinks driving is a Big challenge to you.
Oh, thank God you’ve come along. I’ve been waiting for you. Clearly, I’m an idiot and bringing down the entire country that I have been faithfully serving for the past 23 years.

“Me thinks” the others that have provided helpful responses know exactly what I’m asking. Just looking at a handful of your posts on the forum confirms that you’re pretty rough around the edges when talking to people and frequently just insult rather than help.

Enjoy your 4th of July, Jimbo and Live a Life Worth Their Sacrifice.
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Old 07-05-2022, 08:04 AM   #13
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As NXR said, " If it was that low for any length of time and especially if it was driven on for any distance that tire should be considered to be irreparably damaged.

My first thought as well. I would be very leery of driving on that tire even at the new pressure.
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Old 07-05-2022, 02:25 PM   #14
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Quote:
Originally Posted by cjd10
As NXR said, " If it was that low for any length of time and especially if it was driven on for any distance that tire should be considered to be irreparably damaged.

My first thought as well. I would be very leery of driving on that tire even at the new pressure.
The pic is from Michelin's RV tire manual.

Ray
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