From a little research, there is no DOT or RMA or other Speed rating applicable to ST tires. Each manufacturer of course can set their own speed recommendations. And the majority seem to like 65 mph or 75 mph max. The basis for the ST design standard is to provide more load capacity. In general, they have rubber compounds that are less age sensitive, less tread depth, and stiffer sidewalls. They are made with heavier plies and may be prone to more heat buildup everything else being equal. They may wear faster but are not designed to wear out but rather to be replaced before they "wear out".
It is interesting to note that Goodyear also identifies a G614 Unisteel LT235/85R16 specifically for 5th wheel and travel trailer use. The implication is that ST tires should be used in place of P-metric Passenger Tires but that LT tires may also be used for trailers so long as load and pressure guidelines are followed. And since LT tires are typically designed for significantly higher speeds even at full load, they may run cooler than ST tires at a given speed. If I recall correctly the Michelin XPS also shows up in common trailer use as well as Kumho 954 and a Bridgestone all-steel radial that I don't recall the designation for - all of which are LT not ST tires.
Tire Rack specifically says "Also consider that Special Trailer (ST), as well as Light Truck (LT) tires are fully rated for trailer applications. This means ST- and LT-sized tires can carry the full weight rating branded on the sidewalls when used on a trailer."
As to warranty issues, I see nothing in the Goodyear warranty that addresses invalidating the warranty at 66 mph - there are abuse exclusions such as racing and spin-up (drag racing) and overload, but I don't think a reasonable dealer would claim a tread separation (typically considered a manufacturing defect) was the result of driving at 70 MPH - but neither would I be bragging about driving 85-90 mph (nor would I be driving even 80 mph sustained speed pulling a big trailer at max load).
But all in all I would prefer to have a good LT tire with sufficient load capacity to an ST tire with similar capacity. I've seen a lot more ST failures than LT failures but in either case, at least we can agree that "Overloading and/or failure to maintain correct inflation" are significant causes of tire failure.
best, Ed
The following is from Goodyear
"What is the difference in a trailer specific tire and regular passenger tire?
Trailer tires are considered a special category in the current global design standards of Tire and Rim. The major difference is that trailer tires are required to carry 10% more load than an equivalent P-metric size tire. LT type tires are actually on a lower formula and would require a significant size or load change to meet the trailer load requirements.
In the design process, we evaluate what works best under trailer applications/conditions. We typically find that a narrower tread width and a shallower non-skid (tread depth) provides a better overall performance in a free rolling position. This is one case where wider is not better. There are significant design differences with these tires and this explains why trailer tires are in a special category. In addition, that is why we recommend using trailer designed or trailer specific tires in trailer towable applications."
This is what Tire Rack says
There are differences in the driving requirements between the tires on your trailer and those on the car or light truck you used to tow it. Therefore there are distinct differences between the way trailer tires and tow vehicle tires are engineered."Trailer Tires vs. Passenger Vehicle Tires
Your tow vehicle is a leader, which means traction is a key focus in the design of its tires. Traction allows your tow vehicle to accelerate down the road, turn around the corner and brake to a stop. Another important consideration is tow vehicle tires are designed for ride comfort, which is achieved in part by allowing their sidewalls to flex.
Your trailer is a follower, which often makes tire sidewall flexing a negative. Sidewall flexing on trailers, especially those with a high center of gravity (enclosed/travel trailers) or that carry heavy loads, is a primary cause of trailer sway. Typical passenger radial tires with flexible sidewalls can accentuate trailer sway problems. The stiffer sidewalls and higher operating pressures common with Special Trailer (ST) designated tires help reduce trailer sway.
Also consider that Special Trailer (ST), as well as Light Truck (LT) tires are fully rated for trailer applications. This means ST- and LT-sized tires can carry the full weight rating branded on the sidewalls when used on a trailer.
However when P-metric or Euro-metric tires are used on a trailer, the load capacity branded on the sidewalls must be reduced by 9%. This means P-metric or Euro-metric tires with a maximum branded load rating of 1,874 lbs. for use on a car is only rated to carry 1,705 lbs. when used on a trailer.
Comparing the load capacities of a pair of tires of the same dimensions fitted to a single axle trailer, ST225/75R15 Load Range C-sized tires inflated to their maximum of 50 psi provide 4,300 lbs. of load capacity, where P225/75R15 Standard Load-sized tires inflated to their maximum of 35 psi would be limited to 3,410 lbs. of load capacity, a total reduction of 890 pounds.
Trailers will be more stable and pull better on tires designed specifically for trailer use. Since Special Trailer (ST) tires are constructed with heavier duty materials, they are tougher than typical passenger vehicle tires. This is a plus because trailer suspension systems are generally stiffer and less sophisticated than automotive suspension systems.
Special Trailer (ST) Tire Speed Ratings
Industry standards dictate tires with the ST designation are speed rated to 65 MPH (104 km/h) under normal inflation and load conditions.
However Goodyear Marathon and Power King Towmax STR tires featuring the ST size designation may be used at speeds between 66 and 75 mph (106 and 121 km/h) by increasing their cold inflation pressure by 10 psi (69 kPa) above the recommended pressure for the rated maximum load.
Do not exceed the wheel’s maximum rated pressure. If the maximum pressure for the wheel prohibits the increase of air pressure, then maximum speed must be restricted to 65 mph (104 km/h).
The cold inflation pressure must not exceed 10 psi (69 kPa) beyond the inflation specified for the maximum load of the tire.
Increasing the inflation pressure by 10 psi (69 kPa) does not provide any additional load carrying capacity."
On 3/12/2014 6:21 PM, Ryan Hill wrote:
From what I have gathered in talking to tire professionals in the past regarding speed ratings on trailer tires, an ST (special trailer) tire has a 65 mph speed rating, period. Goodyear offers an STR version of their Marathon which is rated to 75 mph, as I recall. (other manufacturers probably also offer a higher speed rating)
An LT is a 'Light Truck' tire which is not recommended for trailer use but can be used for lighter trailers due to the stiffer sidewalls. I only use Goodyear Marathon's on my boat trailers, this is based on what I've read about the quality and performance of most other brands on the market.
I hear a lot of people mentioning multiple blowouts on their tandem trailers when towing their 300's around. It's important to understand that when a tire blows because it's been broken down by excessive heat caused by under-inflation or sustained high speed (abuse) etc. that the other tires likely are breaking down equally and will also fail. If you blow a tire on a tandem, you really should replace at least the other tire on that same side because it probably sustained damage when the additional load was applied to it alone.
Ryan Hill
Date: Wed, 12 Mar 2014 16:23:24 -0500
From: millserAT@xxxxxxxxxxxxx
To: ryan_hillc300@xxxxxxxxxxx
Subject: Re: [Chrysler300] Trailer Size?
My mistake the original post said 65 mph for ST tires not 60 mph - If thats a real limit on the safe speed for ST tires, in my experience, I doubt that many people towing trailers respect that limit. Around here on the Interstate, 75 is more the norm with a trailer - 65 would get you run over by the 18-wheelers.
On 3/12/2014 4:14 PM, Edward Mills Antique Tractors wrote:
I'll have to go check my trailer tires tomorrow but I'll bet you that my trailer tires do NOT have a speed rating - I'm pretty sure the table you have found applies to Passenger Tires or maybe Passenger and Light Truck - the only question is whether there is a designation marked on ST trailer tires where us stupid people can find it. If it is in fact 60 mph what letter would that be? I, J, K? As for the manual - when is the last time you got a manual with a trailer? I've bought 2 new trailers and neither had any paperwork other than the registration.
On 3/12/2014 3:18 PM, Ryan Hill wrote:
Every tire that is DOT approved does have a specific speed rating on the sidewall, it's designated by a letter. A specific speed limit or warning on the sidewall is not necessary; it is your responsibility as the operator of a vehicle to know it's limitations. For the vast majority of motorists who don't even care to understand or pay any attention to these details, this is why a reputable tire salesmen always ask how you drive your vehicle and what you use it for. I would suspect a manual from the trailer manufacturer would recommend and/or warn new buyers of tire limitations.
If I'm not mistaken, maximum tire speed ratings are based on a sustained speed for a specific period of time. The following is an excerpt from Tirerack.com:
L 75 mph 120 km/h Off-Road & Light Truck Tires M 81 mph 130 km/h Temporary Spare Tires N 87 mph 140km/h
P 93 mph 150 km/h
Q 99 mph 160 km/h Studless & Studdable Winter Tires R 106 mph 170 km/h H.D. Light Truck Tires S 112 mph 180 km/h Family Sedans & Vans T 118 mph 190 km/h Family Sedans & Vans U 124 mph 200 km/h
H 130 mph 210 km/h Sport Sedans & Coupes V 149 mph 240 km/h Sport Sedans, Coupes & Sports Cars
W 168 mph 270 km/h Exotic Sports Cars Y 186 mph 300 km/h Exotic Sports Cars
While a Z-speed rating still often appears in the tire size designation of these tires, such as 225/50ZR16 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire's 168 mph, 270 km/h maximum speed.
225/50ZR16 in excess of 149 mph, 240 km/h 205/45ZR17 88W 168 mph, 270 km/h 285/35ZR19 99Y 186 mph, 300 km/h
Most recently, when the Y-speed rating indicated in a service description is enclosed in parentheses, such as 285/35ZR19 (99Y), the top speed of the tire has been tested in excess of 186 mph, 300 km/h indicated by the service description as shown below:
285/35ZR19 99Y 186 mph, 300 km/h 285/35ZR19 (99Y) in excess of 186 mph, 300 km/h
Ryan Hill
To: hmpirish@xxxxxxxxxxxxx; LabLoverDC@xxxxxxx; billandmarilynallen@xxxxxxxxx
CC: jymopar@xxxxxxxxxxxxxxx; mwl1967@xxxxxxx; Chrysler300@xxxxxxxxxxxxxxx
From: millserat@xxxxxxxxxxxxx
Date: Wed, 12 Mar 2014 14:33:48 -0500
Subject: Re: [Chrysler300] Trailer Size?
As to tires, any restrictions on Speed should be identified in the fine print on the sidewalls - if it is not I would argue their negligence in not providing such information - I know on the implement tires used on farms, there is a limitation in relatively large print not to exceed 25 or 30 mph or such - I thought it was a DOT requirement.
Supposedly there are subtle differences in rubber compounding that address the longer service age typical of trailers. I have no-name ST235/80R16 Load Range E tandem wheels on my smaller trailer and Michelin XPS Rib LT235/85R16 Load Range E dual tandems on my bigger 20k pound trailer.
Both have heavier axles than required and the only problem I have ever had with either at speeds to 80 mph was 2 of the original Continental LT235/85R16 chunking on a hot day - noticed it on all 4 front tires before tires were a real problem (typically more side scrub loads on front). Tires were about 5 years old - 2 were pretty badly chunked. Replaced all 8 with Goodrich Commercial TA at closest Sams (only close place that had more than 6 name brand tires in stock) - Goodrich gave me NO problem for several years and I watched close - then they were recalled and I got the Michelins free.
I had previous similar chunking issues on OE Continental tires on my F250 at about 4 years - Ford dealer said common problem with them - no warranty credit unless I replaced with Continentals which he did not recommend!!! He sold me Goodyears which worked well for about 30k miles til one blistered badly - again no joy from selling Ford dealer (who incidentally has done all service on my truck from day 1). They also wore much faster than the Continentals. Switched to Michelin at Sams - Very happy except for price.
Several obvious lessons -
1. Go heavier on axles and tires than you plan to use - its safer and relatively cheap when you have trailer built.
2. Watch all tires closely - and by that I mean inflation pressures and tread for signs of problems and sidewalls and tread for cracking.
3. Go with a readily available size, preferably in a name brand (not Continental - personal thing - see above) - I like Goodrich & Michelin based on both performance and how I was treated in recall.
4. I don't know about what tires normally go with 5200 pound axles, but presumably its at least ST235/80R16 Load Range D (3000 pounds @ 65 psi) or LT235/85R16 Load Range E (3042 pounds @ 80 psi) - I'd stay with one of these as they are reasonably common.
5. Personally I would go with the LT rather than the ST because they are more readily available (and don't have any question of Speed Limitations) - About the only name brand ST are Goodyear - but what you will find on the road is the mostly cheapo stuff (though not necessarily at cheap prices).
6. Carry a good spare preferably under cover to protect from aging.
7. Agree with use of Anti-Sway device on bumper-pull trailers.
On 3/12/2014 12:41 PM, hmpirish wrote:
Hello Shannon,Two other things to think about:Tires - most trailers come with ST radial tires, to give a better ride. However, I learned after going to the Monterrey CA show, that ALL ST tires are speed limited to 65 mph. "All bets are off" with regard to replacement etc., if you exceed 65mph - as I did going across west Texas and New Mexico on I-40 at the posted speed limit of 70mph. I had two failures on one year old tires, and only when replacing them found there was no credit toward the cost of new tires. I was informed of the speed limitation for the first time, never having heard a word from the trailer manufacturer or the tire dealer when the originals were replaced after fours years service.The speed limitation makes sense from the view of economy and safety in general but on a long trip where time is important, it surely was a temptation to go the limit, as I did. A possible solution would be to specifiy LT tires when ordering your trailer, as these do not have the speed limit. They may not fit in the wheel well of the trailer if you don't specify that on ordering - some wells are very "tight" to give max room inside the trailer.Hitch/stabilizer system: From the beginning with my 28ft trailer, the long distance from the front trailer wheels to the hitch point, created a swaying tendency - when being passed by a large bus or 18 wheeler. Especially at interstate speeds the air buble ahead of the passing vehicle would "push" the nose of the trailer sideways, thus the nose of my Ford Excursion (F-250 equivalent) TOWARD the passing bus/truck. This required me to be ready to counter steer to avoid closing toward the bus/truck.The first few times were startling but I quickly adapted to this requirement and "had it under control". I thought!Then one night in the drizzle, an 18 wheeler passed me going at least 25 mph faster than my 60mph. The sideways push was so strong my excursion was pointed right at the tractor's driving wheels in a flash. I corrected back right abruptly and found myself one whole lane to the right of the one I had been driving in. Had any one been in that lane I would have caused a horrific accident.The next day I did my "homework" and invested in a Hensley Arrow hitch which advertises, and DOES, correct this problem completely. I strongly urge anyone with an enclosed trailer to go to their website, hensleymfg.com, and get them to send their information. The life you save may be your own (or your beloved 300's)One additional thought specifically about 26 & 28 ft trailers, you must be especially careful and think about the space they require to maneuver and/or, park in. My rig is 53 ft over all. Many Hotel and Motel parking lots will not handle rigs of this size. Places to stop and eat have the same problem, as do gas stations (my excursion is a gas fuel V-10). Early on I had to back out of a gas station I thought I could pull straight through. My wife directed traffic on the four lane street so I could get out. Not Good for marital bliss as you might imagine.All the Best 300ing,Phil Irish----- Original Message -----From: Joe AllenTo: ShannonSent: Tuesday, March 11, 2014 11:54 PMSubject: Re: [Chrysler300] Trailer Size?
Just another late comment regarding trailers for our Chrysler 300's. . . If by chance anyone is considering a custom two car stacker enclosed trailer, consider the following: Make sure lift has capacity, length and height clearance for 2nd vehicle. For example, my 25 ft trailer has plenty of room for '55 C300 on bottom. My lift has 6,000 lb capacity, but I failed to allow enough length for another 300 letter car, a '56 Dodge, nor a 300M due to improperly placed bracing / ramp door lift, etc. Maximize internal height without exceeding 13' 6" outside through creative frame / platform / suspension design. Triple 7,000 lb axles and special trailer rated tires provide a rating of 21,000 lbs. A steel frame, aluminum skin 25 ft trailer weighs approximately 8,500 lbs empty, 17,000 lbs loaded with two 300's. Such a trailer requires a heavy duty tow vehicle. If the tow vehicle is a motorhome, be sure total length of motorhome, trailer, and hitch assembly does not exceed 65 ft in order to be legal in California and in a few northeastern states. I believe 102" total width is now legal in all states, even California. Make sure trailer is towed perfectly level with load spread evenly over all 3 axles.
Contact me directly regarding specific trailer questions / concerns / ideas. I can share experiences over past 12 years - some good, some bad, some ugly.
Bill Allen
On Sat, Mar 8, 2014 at 10:03 AM, Shannon <LabLoverDC@xxxxxxx> wrote:
I'm a little late weighing in on this, but I second the opinions regarding a minimum of 5200 pound axles. We bought an enclosed 24' Haulmark new, and picked it up at the factory in Georgia to save on shipping. It came standard with 3500 pound axles, which we thought would be sufficient, but we were way wrong. Although we didn't have a letter car then, every time we would load it fairly heavily, we would blow tires. It turned out that you just can't buy a sturdy enough tire with enough of a rating to handle the loads, even if you keep your payload to around 3500 pounds, which would obviously be exceeded with a 300.
Ultimately, we bit the bullet and upgraded to 5200 pound axles. We considered going one size higher (7,000 pound?), but were advised that they may be too stiff for our normal loads, resulting in too much bouncing, and the 5200 pound axles would be better suited to our normal load of 5-6,000 pounds. Since switching axles and going with the highest rated tires, we have not had any problems, and hauled a 300 G a long distance successfully.
Some other trailer thoughts: A load equalizing hitch and an anti-sway bar helped immensely. We added a winch which helps with the loading process a lot. I can't remember if our doors on the G would open above the fender wells; that might be worth looking into, because if they don't, I don't think a drivers side door would do much good. Also, I'm not sure a drivers side door would typically be placed far enough back to enable opening the car door--another point to check.
We've found the 24' adequate for our needs, but wish we had bought a 28', just for the luxury of extra space. Trailers are kind of like garages--they can never be too big. That said, I guess you also have to consider your tow vehicle.
Torsion bar suspension is nice and worth it in my opinion. It also allows the trailer to ride closer to the ground, which makes it less likely to scrape bottom on loading as you go over the hump. A dove-tailed rear is important for the same reason.
We have found our Haulmark to be reasonably well made and it has held up pretty well for a relatively inexpensive trailer. That said, depending on how much use it will get, there are definitely some better made but more expensive trailers out there that may be worth considering, depending upon your budget. We have a 20' enclosed, all aluminum Triton trailer we use for hauling our snowmobiles, and there is a world of difference in the quality, as well as the increased payload as a result of the trailer being lighter. In aluminum trailers, Featherlite is another top brand worth considering, but all of the all aluminum trailers are pricey.
Finally, don't forget to have plenty of tie downs installed in the floor and sides too, if you're hauling things other than cars. Brakes on both axles with a good controller are important, as someone pointed out. I think most modern trailers come with adequate running/side lights. On two of our tow vehicles, we added air bags just to help with the tongue weight, although that may not be necessary.
Good luck with your purchase.
Shannon300 F convertible
Sent from my iPadI agree with other post re trailer, go for 24 ft , 5200 pound axles and get
a driver side door.
300's are heavy up front , I would always put the car front first in the
trailer if you are going to travel any significant distance, for trailer
stability you want a little more weight in front of your axles , not behind
them...my 2 Cents...
As a side note, I pulled into a weight station in Canada once and they gave
me a warning ticket because ; with a regular drivers licence, which is what
I have, you can only haul up to 9,900 pounds,( I did not know that!) and
the trailer with 5200 axles totals 10,400! To fix this, they told me to go
to a DMV and get the trailer weight lowered to 9,900 pounds on the trailer
registration papers ...and that would make it all legal!!
This may not apply to the US...but if it does, and you buy a new trailer ,
you may want to check the towing limit allowed by a regular drivers
licence...
Jean-Yves.
From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On
Behalf Of Mwl1967
Sent: March-04-14 11:02 PM
To: Chrysler300@xxxxxxxxxxxxxxx
Subject: [Chrysler300] Trailer Size?
Hi Everyone,
I'm sure this must have come up at some point in the past but I'd like
to open a discussion as to what to look for in a enclosed trailer sturdy
enough to handle the largest of the 300's. I currently have a 20' open car
carrier with a steel deck that weighs around 2300lbs empty with 3500lb
axles. Add a full size brute to that and I'm running at maximum. Shall I
assume an enclosed trailer same length will then need to upgrade to 5000lbs
axles to cover the weight of the car and the trailer? What about length?
Will a 20' enclosed give me enough room to get in front of the loaded car,
and down on the ground to work the tie downs up front? What about trailer
construction? Why is a Haulmark Edge twice the price of others? Do I need a
door on the drivers side of the trailer to get in and out of the car?
Appreciate any input.
Mike Laiserin
[Non-text portions of this message have been removed]
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Ray Jones. Y'all come on down an see us. Ya hear?
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