Tire pressure in tv

[gsmith31]

I have a question about air pressure in the tv tires. i have heard of guys putting in more air in there tires when they are towing,does anybody here do this?

[2014Fuzion300]

Always use recommended max cold tire pressure!

[theeyres]

Originally Posted by 2014Fuzion300

Always use recommended max cold tire pressure!

x2. Run the recommended tire pressures as stated on the door column.

[bsmith0404]

Originally Posted by theeyres

x2. Run the recommended tire pressures as stated on the door column.

Careful with the door column sticker, different tire manufacturers recommend different pressures for their tires. The door sticker is what got Ford in trouble with the Explorer several years ago as they recommended pressures for better ride (I know not a towing application and many years ago). When I worked for a store as a tire installer I quickly learned that the different tire manufacturers have different recommended pressures for daily driving as well as max payload. Additionally, if you have changed tires to a different load rating or ply than the OE, they will most likely recommend different pressures.

When I tow, I run max cold pressure recommended on the sidewall. When I run empty, I run a pressure that feels comfortable and gives even wear. Even wear indicates that the tire is making maximum contact with the road surface which is the safest condition.

[CWtheMan]

Originally Posted by bsmith0404

Careful with the door column sticker, different tire manufacturers recommend different pressures for their tires. The door sticker is what got Ford in trouble with the Explorer several years ago as they recommended pressures for better ride (I know not a towing application and many years ago). When I worked for a store as a tire installer I quickly learned that the different tire manufacturers have different recommended pressures for daily driving as well as max payload. Additionally, if you have changed tires to a different load rating or ply than the OE, they will most likely recommend different pressures.

When I tow, I run max cold pressure recommended on the sidewall. When I run empty, I run a pressure that feels comfortable and gives even wear. Even wear indicates that the tire is making maximum contact with the road surface which is the safest condition.

It's important to remember that vehicle manufacturers set the recommended tire pressures for your vehicles. NOT the tire manufacturers. As for Ford...that was their error NOT the tire manufacturers.

Recommended cold tire pressures are found on the federal certification label, tire placard and in the vehicle's owner's manual. Deviations - if needed - will also be listed in the owner's manual.

Tire manufacturer charts are often used to increase tire pressures above normal recommendations when the vehicle is heavier than normal. Industry standards NEVER recommend using any tire pressures below the vehicle manufacturer's recommendations.

CW

[jadatis]

Tire pressure advice is all about load on the tire/ maximumm load on tire.
And a bit about speed and alighnment.
So if you can determine the weights on seperate wheels best, second best seperate axles , but if absent we wil have to do with GAWR, GVWR empty weight and the estimated loads and places, you can calculate a pressure that gives the same deflection on tire that it would have when maximum load and pressure needed for that . That is the goal of all the calculations.

I made an adminstrativ study of tire-pressure , and even made spreadsheets for it, and also game by the Ford Explorer/Firestone tires affaire.
this Affaire has had more inpact on how tire pressure advice is handled, then people think.
Also the reason of why in America and from 2014 also in Holland ( where I live) you have tho have some kind of pressure warning system in the car.
Also after about 2000 extreme high advices.
My conclusion is that the Firestone tires had off-road kind of tires with large profile blocks that cover a part of the sidewall , wich make that sidewall less hight to deflect so in fact these kind of tires where given to high maximum load on sidewall.
For somewhat other reason this is also the case for low AR tires ( low hight/width division) , also to high maximum load given on sidewall, so sooner damage to them.

[bsmith0404]

Originally Posted by CWtheMan

As for Ford...that was their error NOT the tire manufacturers.

CW

This was exactly my point. Ford recommended tire pressures on the Explorer lower than the tire manufacturer recommendation because it gave a smoother ride. This caused increased heat and tire failure. The tire manufacturer knows their tire and recommended pressures for max load. MOST are becoming pretty standard and will match the door sticker (auto and tire manufacturers work pretty closely), but if a person has changed tire/wheel size, or tire ply from OE, the door sticker is useless as it only accounts for OE tire specs.

[CWtheMan]

Originally Posted by bsmith0404

Additionally, if you have changed tires to a different load rating or ply than the OE, they will most likely recommend different pressures.

This is true. But, well trained installers will follow industry standards when deviating from the OE tires. Here is a reference that outlines industry standards. It’s a little old but was drawn up to include any changes from the rules enacted in 2007.

http://www.tiresafety.com/images/Tir...t%20Manual.pdf

CW

[bsmith0404]

Originally Posted by CWtheMan

This is true. But, well trained installers will follow industry standards when deviating from the OE tires. Here is a reference that outlines industry standards. It’s a little old but was drawn up to include any changes from the rules enacted in 2007.

http://www.tiresafety.com/images/Tir...t%20Manual.pdf

CW

Yep, have seen and used the guide in the past myself. The only problem, people don't use the guide when deciding on aftermarket oversized tires and wheels to make sure they have the same specs as their OE. People lift trucks, go from a 16" wheel to 20", 245 to 305 (or bigger), metric to high flotation....... I've never seen anyone change the door sticker or add a 50 page "industry standard" guide to the door. The OP never stated if he has OE tires/wheels or something different. My original point was only to "be careful" when using the door sticker if the tires have been changed from OE. I think this guide supports that, thank you for providing it.

As for my statement of adjusting air pressure to achieve even wear, if I set my tires at the recommended pressures from the door sticker, they wear in the center. That is an indication of over inflation (the manufacturer does not know how much load you will put in your vehicle and cannot recommend an air pressure setting for every possible payload on one small sticker. Center wear shows that I'm not getting even contact across the tire and therefore not maximizing the potential grip on the road surface for control. Over time, I have learned what "my" truck and tire combination likes, and I adjust accordingly for different payloads. I go above and beyond what a "normal" person would, but that's just me having taken the time to understand my tires, my truck, and being anal.

[jadatis]

Though the calculation was wrong in American in time of the Ford/Firrestone-affaire, it was sufficiently repaired by reducing the maximum load by 10% for SUV etc. I calculated it back and even came to the same pressure .
But if you fill in the wrong data to laws of nature, the outcome is wrong even with the to laws of nature sound formula.

And that was the real cource , the maximum load given on the firestone tires where to high to laws of nature.
So its a responcibility of the tire maker in that case, and they got the blame , but other reasons where given for being wrong. That where the strikes in some plants wich gave bad glue used . Real reason was to much deflection wich gave the tire-damage.

This all is my own conclusion, so do with it wat you want.

[CWtheMan]

Originally Posted by bsmith0404

Yep, have seen and used the guide in the past myself. The only problem, people don't use the guide when deciding on aftermarket oversized tires and wheels to make sure they have the same specs as their OE. People lift trucks, go from a 16" wheel to 20", 245 to 305 (or bigger), metric to high flotation....... I've never seen anyone change the door sticker or add a 50 page "industry standard" guide to the door. The OP never stated if he has OE tires/wheels or something different. My original point was only to "be careful" when using the door sticker if the tires have been changed from OE. I think this guide supports that, thank you for providing it.

As for my statement of adjusting air pressure to achieve even wear, if I set my tires at the recommended pressures from the door sticker, they wear in the center. That is an indication of over inflation (the manufacturer does not know how much load you will put in your vehicle and cannot recommend an air pressure setting for every possible payload on one small sticker. Center wear shows that I'm not getting even contact across the tire and therefore not maximizing the potential grip on the road surface for control. Over time, I have learned what "my" truck and tire combination likes, and I adjust accordingly for different payloads. I go above and beyond what a "normal" person would, but that's just me having taken the time to understand my tires, my truck, and being anal.

It’s very hard to justify airing any type of RV tires to the load they carry. The TRA says not to use less tire pressure than what is shown on the tire placard. It’s an industry standard that protects the tire industry from reprisals from the vehicle manufacturing industry.

RV owners WILL overload their RVs. It may not be done intentionally but sooner or later it will be done. A friend asks you to take some things home in your RV. Maybe a hundred pounds. The only place to carry the item (s) is on the driver side. OOPS, overloaded at least one tire.

Here is what Toyo has to say about airing RV tires to equal the GVW. Sure, they are talking about motorized RVs. All are DOT certified tires and their logic is sound and complies with industry standards.

http://cache.toyotires.com/sites/def...ire_safety.pdf

RV trailer manufacturers MUST meet the requirements the DOT has in place for safety. In those requirements the DOT has directed the trailer manufacturer to select appropriate tires/rims for each trailer they manufacturer and then set the correct tire pressures for those tires. They then certify that information to be true.

CW

[jadatis]

I have been reprimanded to go off-topic once in this forum, so now will get back to the original question.

so if its needed you should use higher pressure at rear tires when towing.

But I once calculated for my Seat Alhambra Diesel with about 800kg/1760lbs loading capacity , because whe only 2 persons and a little load in the car and the rest in the travel-trailer, that we could use the normal use pressures , even with the weight on tow bar wich is in European traveltrailers about 5% of total weight of TT ( unlike American 10 to 15% ) .
so if you can determine the real load on seperate tires, you can calculate a pressure for that with some reserve and that does not have to be the maximum pressure of tire.
If you rather look it up in a list, dont use old american pressure/loadcapacity lists. American TRA stepped over to the saver European ETRTO calculation as late as 2006, but only for P-tires and XL/extraload/reinforced tires, wich mostly are used on towing vehicles.
Best would be to use the European lists or my made extra save lists.
The old american lists lead to to much deflection of the tire in the lower actual load/maximum load divisions. For LT tires, also often used for TV , the calculation is a bit better and have not been chanched in 2006 so best would be to use for LT also European lists or my made.

[GMcKenzie]

Originally Posted by bsmith0404

When I tow, I run max cold pressure recommended on the sidewall. When I run empty, I run a pressure that feels comfortable and gives even wear. Even wear indicates that the tire is making maximum contact with the road surface which is the safest condition.

Ditto. I don't change my fronts (runs about 70 psi) but will adjust the rears from 55-60 up to 70 when I have the trailer hooked up. Without the trailier, I just don't carry much in the back of the truck and 70 is just too much pressure. Max for the tires is 80.

Simple way to get close to the right pressure. Find a long, paved, secluded road or parking lot. Put a chalk line across the tread, from sidewall to sidewall. Go forward a few feet, maybe 20 or so. See how the chalk line is wearing off. If it wears off evenly, you have a good pressure. If the center wears off sooner, pressure is too high. If the outside wears off sooner, pressure is too low. Repeat with trailer attached.

[rhagfo]

Originally Posted by bsmith0404

........

When I tow, I run max cold pressure recommended on the sidewall. When I run empty, I run a pressure that feels comfortable and gives even wear. Even wear indicates that the tire is making maximum contact with the road surface which is the safest condition.

Originally Posted by GMcKenzie

Ditto. I don't change my fronts (runs about 70 psi) but will adjust the rears from 55-60 up to 70 when I have the trailer hooked up. Without the trailier, I just don't carry much in the back of the truck and 70 is just too much pressure. Max for the tires is 80.

Simple way to get close to the right pressure. Find a long, paved, secluded road or parking lot. Put a chalk line across the tread, from sidewall to sidewall. Go forward a few feet, maybe 20 or so. See how the chalk line is wearing off. If it wears off evenly, you have a good pressure. If the center wears off sooner, pressure is too high. If the outside wears off sooner, pressure is too low. Repeat with trailer attached.

Wow, only two pages before someone agreed with Bsmith0404!
One pressure doesn't fit all, that is for sure. Over inflation leads to harsh ride, poor tire wear, and LESS TRACTION!!! Rears pumped up to 80# in my rears and I spin the heck out of my tires on wet pavement. Running at 45# to 50" far better traction (MORE CONTACT) with the correct pressure for the load.

Those with a TPS, need to check if you can change the level for unloaded TV.

[bsmith0404]

Glad to see I'm not the only one who uses my tires as an indicator for proper inflation vs just following a sticker that gives me two options, empty and loaded. Especially when the difference between the two weights is anywhere in a range up to 3,000 lbs.

[cabinfever]

Since my truck is always working, I run 70LBS front and max rear for my tires. The reason I run max air under loads is to prevent sidewall flex which could damage the tire and lead to failure.

[bsmith0404]

Originally Posted by cabinfever

Since my truck is always working, I run 70LBS front and max rear for my tires. The reason I run max air under loads is to prevent sidewall flex which could damage the tire and lead to failure.

Not much different than I run. 70 up front, 65 rear for daily use, 80 (max) for towing the RV. When I hook up my car trailer, I only run 75 rear, 80 gives me a definite center wear pattern.