75 MPH Westlake Tires?

[CWtheMan]

Look at the picture below. That's a ST225/75R15D tire with a load index on its sidewall. The tire is from Westlake. Load index ratings are not official load indicators for LT or ST tires but can be put on the sidewall at the manufacturer's discursion. The lettering system used to determine the load range for ST and LT tires is currently the only method approved for those tires.

http://www.irv2.com/photopost/showfull.php?photo=27425

Another thing that is very present with that load index is the letter L following the dual load index. That L is a speed symbol used in conjunction with the load index system which constitutes a complete service description. The L is for 75 MPH. I wonder if Westlake really approves their radial ST tires for 75 MPH?

CW

[GaryWT]

Approval or not I know I am not going 75 while towing. I know some do as plenty pass me. I tend to stay under 65 when towing and will go 65 if pushing it.

[theeyres]

I do 65 because that's my trailer tire ratings. Gotta admit, though, with my diesel and small trailer I'd probably do 70 on the freeways if the tires were rated for it.

[Chinomax]

Search "Westlake Tires" One of the 5 worst trailer tires out there. I swapped mine out when I got the rig home. Chino

[bsmith0404]

Interesting that companies are trying to increase speed ratings on tires and for some it is becoming a selling point. Personally, when towing that much weight with a light duty truck we don't need to be going faster. It took the DW a bit to get used to me driving 60-65 when the speed limit is 75, but now she just sits back and reads her book until we get to our destination. My truck gets the best fuel mileage at about 62 and even with fuel prices dropping, I still prefer to save my money by maximizing mileage.

[Bob Landry]

Load rating and speed rating are not the same. I'm not aware of any ST tire that is rated for more than 65 MPH.

[Desert185]

Interesting that companies are trying to increase speed ratings on tires and for some it is becoming a selling point. Personally, when towing that much weight with a light duty truck we don't need to be going faster. It took the DW a bit to get used to me driving 60-65 when the speed limit is 75, but now she just sits back and reads her book until we get to our destination. My truck gets the best fuel mileage at about 62 and even with fuel prices dropping, I still prefer to save my money by maximizing mileage.

Ditto. Other than an increased margin for tire blowout protection, a higher speed rating is a non-issue for me.

[jsmith948]

Approval or not I know I am not going 75 while towing. I know some do as plenty pass me. I tend to stay under 65 when towing and will go 65 if pushing it.

Have to agree. Had a young (thirtyish) guy pass me the other day like I was up on blocks. Pulling his 3 axle toy hauler with a jacked-up 3/4 ton with one wrist laying on top of the steering wheel and tailgating the small suv ahead of him. Obviously in a hurry to get to Pismo!

[CWtheMan]

Load rating and speed rating are not the same. I'm not aware of any ST tire that is rated for more than 65 MPH.

You're right. But, they are related because a tire's maximum load capacity is completely used-up when it reaches its manufacturer's speed limit.

A footnote: There is no speed letter code for 65 MPH.

CW

[christopherglenn]

Load rating and speed rating are not the same. I'm not aware of any ST tire that is rated for more than 65 MPH.

Goodyear g614 are rated to 75.

[NotyetMHCowner]

Kuhmo 857 D load range tires in the 14" size are Q speed rated. I had those on my TT and absolutely loved them. I think they were rated at 75mph but I cant remember. That was one of the reasons for me buying them was the speed rating. I don't want to start an argument, but I don't see anything wrong with 70-75 mph as long as you are well within your tow and load limits and everything is working as it should.

We are upgrading to a fifth wheel soon, so I don't know how I will feel about speed until after pulling for a while, but one of the reasons for buying more truck than I needed, was to have extra safety margin.

[racin500]

This says it pretty clearly. Similar statements on other manufacturers also. Here is what Carlisle says;

How fast can I travel on Carlisle trailer tires?
In the past, most trailer tires were rated at 62 or 65 mph. Today, some of our tires are "rated" (speed symbols) at 87 mph (N), some at 75 mph (L), some at 65 mph (J: ST tires) and some at 62 mph (J: non-metric tires).

Please remember that speed ratings are test speeds and not recommended driving speeds. The ratings apply only to the tire itself, and not a particular vehicle. The speed rating does not mean that the vehicle can be safely operated at the tire's rated speed.

We recommend driving no more than 60 mph when towing a trailer. Please always drive at a safe speed and abide by the posted speed limit.

[CWtheMan]

This says it pretty clearly. Similar statements on other manufacturers also. Here is what Carlisle says;

How fast can I travel on Carlisle trailer tires?
In the past, most trailer tires were rated at 62 or 65 mph. Today, some of our tires are "rated" (speed symbols) at 87 mph (N), some at 75 mph (L), some at 65 mph (J: ST tires) and some at 62 mph (J: non-metric tires).

Please remember that speed ratings are test speeds and not recommended driving speeds. The ratings apply only to the tire itself, and not a particular vehicle. The speed rating does not mean that the vehicle can be safely operated at the tire's rated speed.

We recommend driving no more than 60 mph when towing a trailer. Please always drive at a safe speed and abide by the posted speed limit.

Actually speed letter codes are used in conjunction with the service description format for tires other than LT & ST. Because tire service descriptions are not approved for ST & LT tires a speed rating for them has to be published for each tire or the actual speed rating would have to be written on the tire's sidewall. Carlisle is in error using the letter J for 65 MPH. The letter J identifies tires with service descriptions as being 62 MPH.

CW

[pawpaw]

With so many of the newer tow vehicles coming from the factory with LT275x65x20 tires (34x11) just imagine the difference in rev's per mile between the smaller diameter trailer tires say at 70-75 mph. On a hot day it could be a recipe for disaster! Too many factory trailer tires are minimal quality as it is. I also recommend towing in the 60-62 mph range or a little below the posted limit if lower. Always give yourself enough room to stop in case of an emergency.

[cobalert]

I installed EZ tire pressure temperature and pressure monitors on the trailer, my duel wheels and the front truck axle. It is amazing how your pressure and temps change at different speeds. I have found them to be very accurate and give me the warm fuzzy that I will know something is up before a tire explosion rips my trailer apart as I have seen on a few roadside causalities. Pulling a 404 Chrome with my F350 6.7 diesel I would never feel a tire going down. I have been warned about the China tires and encouraged to get them off as soon as possible. I wonder why a manufacture would still put suspect tires on a rig. Anyone have problems with the China tires?

[CWtheMan]

Load rating and speed rating are not the same. I'm not aware of any ST tire that is rated for more than 65 MPH.

Here is the official statement that ties speed ratings and load capacities together.

"The speed rating of a tire indicates the maximum speed at which it can safely carry a given load at a specified inflation pressure."

Trivia: A loss of a single PSI of inflation pressure equals approximately 1.3% of a tire's load capacity.

CW

[CWtheMan]

I think the condition of not having speed codes on ST tires will come to an end when the situation of ST tires in this document is ironed-out.

The off shore ST tire manufacturers are not going to like having to change their molds. But, if they want to continue having huge monitory concessions from our government I don’t see any way around it.

http://kenjonestiresblog.com/blog/st-type-trailer-tires-exempt-from-china-countervailing-duties/

CW

[Ken / Claudia]

Going back to early 80s and some years since. At the track, during classroom for pursuit driving. Instructors would cover tires. As I recall they said the speed rating of a tire meet that it was tested to hold together for that speed for 90 mins(as I recall) not all day. Not sure if that is true today or for trailer tires. But, it always makes me wonder when some report tires blowing up, were they driving to fast for to long. If they were not overloaded or under the correct psi. Any thoughts or facts if the speed traveled is the max. speed rated, is it OK all day or not?

[CWtheMan]

Keystone has a long history of using tires with the very minimum load capacity. It's as much NHTSA's fault for not forcing the use of reserve load capacities for RV trailer axles. I'll start a new topic with the specifics.

CW

[JimQ]

I also will keep it at 60 mph while towing. It doesn't make any sense to push any component to save a few minutes. I'm not paranoid about safety, but I do like to be safe!!

[Barbell]

I'm with you JimQ. We just replaced the Goodyear Marathons on our Montana after about 25,000 miles. Two tires were starting to separate but we had no problems. Probably would have if we had tried to get much more out of them or were in a big hurry to get somewhere. Even when tires are going bad, moderate speeds and frequent pressure checks may save a lot of grief.