Trailer Tire Facts

[tvanwave]

The following is from the Discount tire webpage. Seems like good information and includes logic for selecting the ST rather than LT tire.



Trailer Tire Applications

• Trailer tires are designed for use on trailer axle positions only. They are not built to handle the loads applied to, or the traction required by, drive or steering axles.
• An "LT" designation on a trailer tire size specifies load range only. It is not designed for use on light trucks.
• Do not mount "ST" or "LT" trailer tires on passenger cars or light trucks.

Inflation

• Always inflate trailer tires to the maximum inflation indicated on the sidewall.
• Check inflation when the tires are cool and have not been exposed to the sun.
• If the tires are hot to the touch from operation, add three psi to the max inflation.
• Underinflation is the number one cause of trailer tire failure.

Load Carrying Capacity

• All tires must be identical in size for the tires to properly manage the weight of the trailer.
• The combined capacity of the tires must equal or exceed the Gross Vehicle Weight (GVW) of the axle.
• The combined capacity of all of the tires should exceed the loaded trailer weight by 20 percent.
• If the actual weight is not available, use the trailer GVW. If a tire fails on a tandem axle trailer, you should replace both tires on that side. The remaining tire is likely to have been subjected to excessive loading.
• If the tires are replaced with tires of larger diameter, the tongue height may need to be adjusted to maintain proper weight distribution.

Speed

• All "ST" tires have a maximum speed rating of 65 mph.
• As heat builds up, the tire's structure starts to disintegrate and weaken.
• The load carrying capacity gradually decreases as the heat and stresses generated by higher speed increases.

Time

• Time and the elements weaken a trailer tire.
• In approximately three years, roughly one-third of the tire's strength is gone.
• Three to five years is the projected life of a normal trailer tire.
• It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

Mileage

• Trailer tires are not designed to wear out.
• The life of a trailer tire is limited by time and duty cycles.
• The mileage expectation of a trailer tire is 5,000 to 12,000 miles.

Why Use An "ST" Tire

• "ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
• The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
• The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
• "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking.

Storage

• The ideal storage for trailer tires is in a cool, dark garage at maximum inflation.
• Use tire covers to protect the tires from direct sunlight.
• Use thin plywood sections between the tire and the pavement.
• For long term storage, put the trailer on blocks to take the weight off the tires. Then lower the air pressure and cover the tires to protect them from direct sunlight.

Maintenance

• Clean the tires using mild soap and water.
• Do not use tire-care products containing alcohol or petroleum distillates.
• Inspect the tires for any cuts, snags, bulges or punctures.
• Check the inflation before towing and again before the return trip.

Keys to Avoiding Trouble

• Make sure your rig is equipped with the proper tires.
• Maintain the tires meticulously.
• Replace trailer tires every three to five years, whether they look like they're worn out or not.

[lewster]

INteresting, as every other tire shop sells 'LT' tires as LIGHT TRUCK and every truck/van I have recently owned came from the manufacturer with this rating on the tires.

[Wingeezer]

Some interesting info there.

I am about to replace my tires at age 5 years. I thought I was being overly conservative, but this table suggest 3-5 years! Of course one wonders if the recommendation might be a bit self-serving on the part of Discount Tire!

The other thing they say that caught my eye was to always inflate the tire to the maximum psi indicated on the tire.

I had thought that you were supposed to pressure the tires in accordance with the tire manufacturers load-pressure table, which is what I have done in the past.

Something I read on one manufacturer's website (forget which) for ST tires is that if you intend to run up to 75mph rather than 65, then increase the pressure by 10psi over the table rating as long as that wouldn't put it over the stated max for the tire.


All very interesting!

I have just started to shop for tires and hoped to buy Maxxis LRE but cannot find any.

Seems my choice now is to buy Maxxis LRD (I presently have GYM's LRD) or I could get
Carlisle LRE.

I thought that LRE might give me a little more of a hedge against likeliness of blowout but I'm really not sure Which way to go.

One factor now, if I were to follow Discount's recommendation and air up the LRE to its max, I think that is about 80psi. That is getting closer to the max psi rating of my rim which I have been told is 95psi.

The whole issue of tires sure seems complex than you'd think and with lots of contradictory info floating around!

Brian

[tvanwave]

Originally Posted by Wingeezer

Some interesting info there.

One factor now, if I were to follow Discount's recommendation and air up the LRE to its max, I think that is about 80psi. That is getting closer to the max psi rating of my rim which I have been told is 95psi.

Brian

95 psi for a rating on the rim? I wonder what my '91 rims are rated for. Thats only a 15 PSI cusion - would that be enough margin to account for heat related pressure increases? Yes, tires seem to have a lot if variables to consider. My main worry is blowouts. My TT GVWR is 8900 pounds but with 6 tires at 2200 lb each there seems to be enough of a weight margin.

[Wingeezer]

Originally Posted by tvanwave

95 psi for a rating on the rim?.

Well, that isn't something that I have verified with the manufacturer (Alcoa) but is info I found on this forum.

I plan t verify the info.


I did note on the website for Carlisle Load Range E trailer tires, they say
"HD Rims required."

I'm not sure what "Heavy Duty Rims" really means! Wish people wouldn't use terms like that, unless of course it is some industry recognized terms with a specific meaning.

I hadn't really intended to inflate the tires to their max anyway though, I was going to follow the Carlisle load chart for the weight of my trailer.

Actually still wrestling in my mind with which tires to get, D or E, I'm leaning towards "E" !


Brian.

[dznf0g]

I've got issues with some of their statements!

HMMMMMM....ST means special trailer and LT means light truck, for one.

[tvanwave]

From newrver.com they say LT tires are not a good option for a trailer:

Which Type of Tire to Use
Tires are engineered specifically for different types of vehicles. Passenger car tires are designed to provide a soft ride and grip the road during turns and adverse weather. Light truck tires have stiffer sidewalls in order to carry heavier loads, but also are engineered for safe handling and road gripping ability. Trailer tires, on the other hand, are designed to give a soft ride and to slide sideways or scrub the road while cornering. Because of these differences, never put light truck tires on a trailer. Some people think that if the tire is good enough for a truck it must be good enough for a trailer, but this is a fallacy. Light truck tires are not engineered for the unique stresses of trailering.

[dznf0g]

Originally Posted by tvanwave

from newrver.com they say lt tires are not a good option for a trailer:

which type of tire to use
tires are engineered specifically for different types of vehicles. Passenger car tires are designed to provide a soft ride and grip the road during turns and adverse weather. Light truck tires have stiffer sidewalls in order to carry heavier loads, but also are engineered for safe handling and road gripping ability. Trailer tires, on the other hand, are designed to give a soft ride and to slide sideways or scrub the road while cornering. Because of these differences, never put light truck tires on a trailer. Some people think that if the tire is good enough for a truck it must be good enough for a trailer, but this is a fallacy. Light truck tires are not engineered for the unique stresses of trailering.

true 'dat!

[Wingeezer]

Originally Posted by tvanwave

From newrver.com they say LT tires are not a good option for a trailer:

Which Type of Tire to Use
Tires are engineered specifically for different types of vehicles. Passenger car tires are designed to provide a soft ride and grip the road during turns and adverse weather. Light truck tires have stiffer sidewalls in order to carry heavier loads, but also are engineered for safe handling and road gripping ability. Trailer tires, on the other hand, are designed to give a soft ride and to slide sideways or scrub the road while cornering. Because of these differences, never put light truck tires on a trailer. Some people think that if the tire is good enough for a truck it must be good enough for a trailer, but this is a fallacy. Light truck tires are not engineered for the unique stresses of trailering.

Not at all disputing what you are quoting, but it is interesting that I read (either earlier in this thread or elsewhere) that Jackson centre will now put on 16" wheels and LT tires in their service centre as an option!

You'd think they would have done some homework on this issue. Maybe!

Brian

[halimer]

I was at AS one month ago and AS is offering 16" Michelin and Goodyear LT tires in LRE.
They are also offering Towmax STR (15") tires.
Maxxis makes the 8008 225/75x15 in LRE.
M8008 ST Radial

I will be installing Michelin LTX MS 225/75x16 LRE on my AS. I spoke to 2 different individuals at Michelin concerning tire pressures for the LTX's. They recommended, if possible that you get separate weights for each tire when the trailer is loaded. Call them with the weights and they will give you recommended tire pressures.

Mark

[Shacksman]

Originally Posted by tvanwave

Time

• Time and the elements weaken a trailer tire.
• In approximately three years, roughly one-third of the tire's strength is gone.
• Three to five years is the projected life of a normal trailer tire.
• It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

Mileage

• Trailer tires are not designed to wear out.
• The life of a trailer tire is limited by time and duty cycles.
• The mileage expectation of a trailer tire is 5,000 to 12,000 miles.
• Replace trailer tires every three to five years, whether they look like they're worn out or not.

Glad I didn't read this years ago or I would have changed tires 4 times, based on time and miles, by now instead of keeping the Sumitomo LT 700 X 15 Radials that I put on in 2003.
5,000 - 12,000 miles? I would hate to change tires before and during a long trip.

[Cracker]

Originally Posted by Shacksman

Glad I didn't read this years ago or I would have changed tires 4 times, based on time and miles, by now instead of keeping the Sumitomo LT 700 X 15 Radials that I put on in 2003.
5,000 - 12,000 miles? I would hate to change tires before and during a long trip.

The suggested tire life sounds like a plan to sell more tires! As for the inflation pressures - if I had used the max pressure (as suggested) for the rear tires on my dually I would have been divorced over 6 years ago! Nor does the pressure statement comply with Airstream's recommendation for the trailer tires. I believe that many of us are in agreement about a tire life of around 5 years - but that too can be affected by usage. A bit more study and review of other airforum threads will provide a lot of information from which to make your own educated decision!

[pattonsr]

Mark,

What wheels is the factory installing for 16" tires? 16x6 or 16x7 and what brand?

barry

[driftless]

From Tirerack.com, another web site filled with tire information:

Service Type

Most tire sizes begin with a letter or letters that identify the type of vehicle and/or type of service for which they were designed. The common indicators are as follows:

P225/50R16 91S
P = When a tire size begins with a "P," it signifies the tire is a "P-metric" size that was designed to be fitted on vehicles that are primarily used as passenger vehicles. This includes cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity). The use of P-metric sizes began in the late 1970s and they are the most frequently used type of tire size today.
225/50R16 92S
If there isn't a letter preceding the three-digit numeric portion of a tire size, it signifies the tire is a "Metric" size (also called "Euro-metric" because these sizes originated in Europe). While Metric tire sizes are primarily used on European cars, they are also used on vans and sport utility vehicles. Euro-metric sizes are dimensionally equivalent to P-metric sizes, but typically differ subtly in load carrying capabilities.
T125/90D16 98M
T = If a tire size begins with a "T," it signifies the tire is a "Temporary Spare" ("space saver" or "mini spare") that was designed to be used temporarily only until a flat tire can be repaired or replaced.
LT245/75R16 108/104S
LT = If a tire size begins with "LT," it signifies the tire is a "Light Truck-metric" size that was designed to be used on vehicles that are capable of carrying heavy cargo or towing large trailers. This includes medium and heavy-duty (typically 3/4- and 1-ton load capacity) pickup trucks, sport utility vehicles and full-size vans. Tires branded with the "LT" designation are the "little brothers" of 18-wheel tractor-trailer tires and are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.
7.50R16LT 112/107Q, 8.75R16.5LT 104/100Q or 31x10.50R15LT 109Q
LT = If a tire ends with "LT," it signifies the tire is either an earlier "Numeric", "Wide Base" or "Flotation" Light Truck size designed to be used on vehicles that are capable of carrying heavy cargo and towing trailers (Numeric sizes), use 16.5-inch diameter rims (Wide Base sizes) or are wider, oversized tires designed to help the vehicle drive on top of loose dirt or sandy surfaces (Flotation sizes). This includes light, medium and heavy-duty (typically 1/2-, 3/4 and 1-ton load capacity) pickup trucks and sport utility vehicles. Tires branded with the "LT" at the end of their size designation are also the "little brothers" of 18-wheel tractor-trailer tires and are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.
195/70R15C 104/102R
C = If a Euro-metric sized tire ends with a "C," it signifies the tire is a "Commercial" tire intended to be used on vans or delivery trucks that are capable of carrying heavy loads. In addition to being branded with the "C" in their size, these tires are also branded with their appropriate Service Description and "Load Range" (Load Range B, Load Range C or Load Range D).
ST225/75R15
ST = If a tire size begins with "ST," it signifies the tire is a "Special Trailer Service" size that was designed to only be used on boat, car or utility trailers. ST-sized tires should never be used on cars, vans or light trucks.


Since my Ram 1500 came with factory mounted Goodyear Wranglers, P265 70R17, it would seem to conform to the above description of service type for a 1/2 ton pickup. Since they have to be replaced before winter I may have to bump up to LT tires because I tow not only the AS but a 14 foot heavy utility trailer. Anyone care to comment on that option?

[Arrowstream]

I understood that tire pressure was a function of load as opposed to pumping them up to the max. Here are two websites that chart pressure vs. load for RV tires.

http://www.goodyear.com/rv/pdf/rv_inflation.pdf

Michelin North America RV Load & Inflation Tables

The Storage section of the original post conflicts with itself:

The ideal storage for trailer tires is in a cool, dark garage at maximum inflation.


For long term storage, put the trailer on blocks to take the weight off the tires. Then lower the air pressure and cover the tires to protect them from direct sunlight.


I store mine at low pressure.

[xonvldz]

dont know if this is right or not ,but hit a pothole with my rear gym st tire and caused a bubble.decided to replace rear axle tires with e rated maxxis tires.now run the front axle gym d rated tires at 65 psi and run the e rated maxxis tires at 70 psi on back axle.when d rated tires need replacing ill move the e rated tires to the front axle and put new e rated tires on the back axle.trailer feels much better with this setup then before with the 4 d rated gyms.tire man told me this was fine as long as i kept inflation close on on all 4 tires and didnt mix load ranges on the same axle.

[dsrtgrls]

how about rotating the as spare.? doea anbody rotate the spare onto the as and when? or not at all?

[Inland RV Center, In]

Originally Posted by xonvldz

dont know if this is right or not ,but hit a pothole with my rear gym st tire and caused a bubble.decided to replace rear axle tires with e rated maxxis tires.now run the front axle gym d rated tires at 65 psi and run the e rated maxxis tires at 70 psi on back axle.when d rated tires need replacing ill move the e rated tires to the front axle and put new e rated tires on the back axle.trailer feels much better with this setup then before with the 4 d rated gyms.tire man told me this was fine as long as i kept inflation close on on all 4 tires and didnt mix load ranges on the same axle.

The tires on the front and rear axles, "MUST" be the same exact size.

Measure the overall width of each brand tire. Tire widths between brands are not always the same.

If you find a difference in dimensions, then the larger of the tires will carry more weight that they should, as well as the smaller tires will carry less weight than they should.

This can set up a sway condition, but most importantly, one axle can then be overloaded that is using the larger tires.

That can be damaging to the axle rubber rods, and the tires as well.

Andy

[48Bob]

Driftless - Our new 2010 Dodge Ram 1500 came with LT tires on it. In the past, I have always had sidewall problems with P metric tires on pickups. The sidewalls are thinner and more prone to puncture that the LT tires. But then again, this might be a function of my actually using my pickups off of the pavement! We do a lot of miles on gravel and dirt roads, both with and without a trailer of some type. Aired up to the proper presssure, I don't notice any difference in ride between the P and LT tires. But then again, it is a pickup. I have also towed a very heavy steel four horse trailer with LT tires on it for many miles over all types of roads with virtually no tire problems. That is one reason that I changed the 15" ST 's on our 20' single axle Safari SE to 16" LT tires. Just my two cents worth.

[Ganaraska]

trailer tire facts or pipe dream