Correct air pressure

[DieselDrax]

Originally Posted by rockfordroo

Seems odd that a reputable tire shop would install tires on a wheel that is not qualified for the full pressure of the tire, bu then again......

Happens all the time, mostly with tires that are not an approved width for the wheel they're being mounted on. I've also seen tire shops install tires that don't have enough load capacity for the truck's GVWR (Replacing LR E tires with lower load range or even P-metric). I can't recall any tire shop actually stopping to check if the wheels have enough capacity when I've had tires on my 3/4 and 1-ton trucks replaced, they just throw them on.

[jaherbst]

That's what the index is for. They check the book against your year make and model. It is up to you to inform them if you have changed the rims. Otherwise there are a range of sizes and tires to fit your model. I would not assume a reputable tire shop would do it any other way. If you are on the cheap and order tires online it is your responsibility to conform to these standards.

Jack

[DieselDrax]

Originally Posted by jaherbst

That's what the index is for. They check the book against your year make and model. It is up to you to inform them if you have changed the rims. Otherwise there are a range of sizes and tires to fit your model. I would not assume a reputable tire shop would do it any other way. If you are on the cheap and order tires online it is your responsibility to conform to these standards.



Jack

That doesn’t address the problem I mentioned initially, putting higher rated tires on wheels that don’t have the same load or pressure rating. You cannot put LRE tires on wheels that came with LRC tires initially and assume the wheels will be OK to run 80psi instead of 50psi. You must check the wheel rating before you just inflate them up to 80psi and think you’ll be fine.

[jaherbst]

Originally Posted by DieselDrax

That doesn’t address the problem I mentioned initially, putting higher rated tires on wheels that don’t have the same load or pressure rating. You cannot put LRE tires on wheels that came with LRC tires initially and assume the wheels will be OK to run 80psi instead of 50psi. You must check the wheel rating before you just inflate them up to 80psi and think you’ll be fine.

Read it again, that's exactly what I said. The reference book for tires using model and year takes into consideration the standard OEM tire and rim to give you a choice of tires. Read it again.

Jack

[DieselDrax]

Originally Posted by jaherbst

Read it again, that's exactly what I said. The reference book for tires using model and year takes into consideration the standard OEM tire and rim to give you a choice of tires. Read it again.



Jack

I read it fine the first time, I don’t know of any tire shops that have this info for trailers. They always end up asking for the tire size and maybe load range, but I’ve never had a shop, whether it’s a reputable chain or mom n pop, actually check the wheel ratings before installing a higher load range tire onto the wheels.

And as I said before, I’ve seen trucks with underrated tires installed.

Just because the index exists doesn’t mean it’s complete or actually being used.

[5picker]

Originally Posted by babock

Use this:

https://www.maxxis.com/trailer/trail...nflation-chart

^^THIS^^
Why would you inflate them to anything other than what is recommended by the manufacturer for a given load?

[TCedmon]

I’m a little confused.

I have a 2017 Wildwood X-Lite 201BHXL; the sticker on my unit for says tire pressure should be 50 PSI for the ST205/75R14’s that came on the unit. I plan on upgrading to the Goodyear Endurance ST205/75 R14’s the Goodyear specs say Max Inflation Pressure of 65 PSI.

So do I inflate to 65 PSI to match the Tire rating or only to 50 PSI to match the Trailers sticker? I’m assuming 65 PSI?

Note: I did notice on the Forest River site that this year's 2019 Wildwood 201BHXL model the stickers say’s 65 PSI; I’m guessing that forest river has upgraded the tires?

[5picker]

There shouldn't be any confusion.
Once you change from factory stock tires, the stickers on the R/V are no longer valid for the replacement tire.

At that point, inflate the new tires to the manufacturers recommended inflation for the load placed on the tire. Don't know the loaded weight? Get it scaled.

Yes, it's that simple!

[DieselDrax]

Originally Posted by 5picker

There shouldn't be any confusion.
Once you change from factory stock tires, the stickers on the R/V are no longer valid for the replacement tire.

At that point, inflate the new tires to the manufacturers recommended inflation for the load placed on the tire. Don't know the loaded weight? Get it scaled.

Yes, it's that simple!

Don’t have scales nearby? Use the trailer’s GVWR and inflate the tires to the pressure needed for that weight using the inflation chart for the tires.

[jaherbst]

Originally Posted by 5picker

There shouldn't be any confusion.
Once you change from factory stock tires, the stickers on the R/V are no longer valid for the replacement tire.

At that point, inflate the new tires to the manufacturers recommended inflation for the load placed on the tire. Don't know the loaded weight? Get it scaled.

Yes, it's that simple!

I fully agree and must add check your rims for max inflation if other than OEM tires.

Jack

[67L48]

Originally Posted by jaherbst

[...] check your rims for max inflation if other than OEM tires.

Certainly no harm in doing that. But, this is a red herring. Any modern trailer is going to have wheels rated between 80 - 110 psi ... well beyond anything we're talking about here.

As has been said about 943 times in about 341 different ways:
1) Ignore stock tire pressure guidance if you're not using stock tires
2) Either run at the ST tire's max pressure or run according to the tire manufacturer's recommendations for pressure vs load
3) If you don't know your load, either have it weighed (scales) or use the GVWR as the worst case scenario.

Done and done.

[Airdale]

Originally Posted by TCedmon

I’m a little confused.

I have a 2017 Wildwood X-Lite 201BHXL; the sticker on my unit for says tire pressure should be 50 PSI for the ST205/75R14’s that came on the unit. I plan on upgrading to the Goodyear Endurance ST205/75 R14’s the Goodyear specs say Max Inflation Pressure of 65 PSI.

So do I inflate to 65 PSI to match the Tire rating or only to 50 PSI to match the Trailers sticker? I’m assuming 65 PSI?

Note: I did notice on the Forest River site that this year's 2019 Wildwood 201BHXL model the stickers say’s 65 PSI; I’m guessing that forest river has upgraded the tires?

The tire size is the same, only the load range changed. At 50 PSI both the OE tire and the replacement provide the same load capacity at 50 PSI so the tire placard is still valid. Recommended tire pressures on certification labels/tire placards are minimum recommendations. However, before increasing the inflation pressure beyond 50 PSI you should insure the wheel is certified for the higher pressure. The same goes for the valve stems.

[Littlehouse]

No expert here, but doesn't max pressure mean MAX pressure? So if you inflate them to that cold, and then run them, as the tires heat up, the pressure increases past max, and then BOOM....imho

[DieselDrax]

Originally Posted by Littlehouse

No expert here, but doesn't max pressure mean MAX pressure? So if you inflate them to that cold, and then run them, as the tires heat up, the pressure increases past max, and then BOOM....imho

That increase is already factored in. The max pressure is when the tire is “cold.”

[Airdale]

Originally Posted by 67L48

Certainly no harm in doing that. But, this is a red herring. Any modern trailer is going to have wheels rated between 80 - 110 psi ... well beyond anything we're talking about here.

As has been said about 943 times in about 341 different ways:
1) Ignore stock tire pressure guidance if you're not using stock tires
2) Either run at the ST tire's max pressure or run according to the tire manufacturer's recommendations for pressure vs load
3) If you don't know your load, either have it weighed (scales) or use the GVWR as the worst case scenario.

Done and done.

The tire industry standards are very specific about replacement tires. In normal circumstances the replacements are going to be the same size and conform to the same tire inflation charts no matter the brand.

In this thread the OP has not changed tire size - load range is not a part of a tire’s size - so the tire placard is still valid.

Whenever a new tire size is chosen - most common is plus sizing - the load capacity for the OE tires is the benchmark for the replacement tires. The tire industry standard is for the replacements to have the ability to provide, at the very minimum, an amount of load capacity equal to what the OE tires provided at their recommended cold inflation pressures. Anything between the new recommended cold inflation pressure and tire sidewall max is optional.

It’s important to remember that only the vehicle manufacturer has the authority to set the recommended cold tire inflation pressures on all tires they install as original equipment. After they set the recommended cold inflation pressures they must certify them. The governing body (NHTSA) validates those certifications. That’s why they are always considered minimum and the tire industry will not knowingly recommend anything less. Again, there are other options, they are between recommended and tire load capacity max.

[Littlehouse]

Originally Posted by DieselDrax

That increase is already factored in. The max pressure is when the tire is “cold.”

Good to know, thanks.

[Airdale]

Originally Posted by Littlehouse

No expert here, but doesn't max pressure mean MAX pressure? So if you inflate them to that cold, and then run them, as the tires heat up, the pressure increases past max, and then BOOM....imho

The maximum pressure for a tire is not established with the individual sidewall numbers. The PSI depicted on the tire sidewall has been established as the inflation pressure needed for the tire to provide it's maximum load capacity.

An explanation of how and when the tire sidewall PSI can be exceeded can be found in FMVSS 571.139.

[67L48]

Originally Posted by Airdale

[...] In this thread the OP has not changed tire size - load range is not a part of a tire’s size - so the tire placard is still valid. [...]

Well played. I enjoy it when people refuse to let this be as simple as it truly is and keep heaping more loads of complexity on top for no reason.

[Nurek]

I'm out of popcorn

[mwdilday]

Originally Posted by csyrell

I'm no expert on tires by any means. However, I do know that when travelling my TPMS shows my tires gaining air pressure as they heat up. Temps and Pressures can even be impacted by the Sun side of the trailer when parked, and especially when driving.

With that, I can't imaging wanting to start out at Max Pressure when the tires are cold. You have zero margin for when the tires heat up and pressure rises. JMHO.

Tires are designed to be inflated up to max pressure cold before driving (or more depending on manufacturer instructions). This max pressure cold allows for increase when driving. You do not have to allow for increase.