Tires on New Trailer

New Marathons (Endurance), Carlisle RH, Carlisle HD and Westlake tires I know as a matter of fact all have speed ratings of 75mph or more.

Its not about driving faster than 65mph, its about having a tire built to withstand higher speed (heat and stress). This is far more meaningful than the false belief that buying higher load rating results in a better tire when you're well within load ratings of either.

My TT manual clearly states not to exceed 65 mph. Until recently most ST tire makers stated 65 mph.

Recently some ST tire makers are recognizing the market for a higher ST speed rating. I expect most will follow suit.

Unfortunately, how fast you can drive, pales in comparison to how fast you can stop.

To the OPs question, how much excess capacity you want is up to the individual.

aftermath wrote:
A friend of ours just purchased a new Trail Runner 24RK trailer. It has a listed GVW of 7600 pounds. It also came with some off brand tire that is a load range C tire. I believe the max weight as per sidewall information is 1720 or maybe 1740 when inflated to the full 50 PSI. So, even at 1750 per tire it would only cover 7000 pounds.

My question is this, is it common practice in the trailer industry to install tires that are underrated for the stated weight rating of the trailer? I would think that such a company could be held liable in the event of an accident caused by the weak tires.

I'm not sure about the situation today, but it was not uncommon to find trailer manufacturers underestimating the amount of stuff people put in travel trailers - and on top of that, they didn't have much reserve (unused) load capacity - not to mention side to side and front to rear load variation.

Personally, I recommend that tires never be operated over 85% of their rated capacity.

Oh, and did I mention that ST tires have a 65 mph speed limitation that is hardly ever mentioned by the trailer manufacturer?

Yup, lots of potential lawsuits there. It's unfortunate that someone has to die for lawyers to be interested.

aftermath wrote:
A friend of ours just purchased a new Trail Runner 24RK trailer. It has a listed GVW of 7600 pounds. It also came with some off brand tire that is a load range C tire. I believe the max weight as per sidewall information is 1720 or maybe 1740 when inflated to the full 50 PSI. So, even at 1750 per tire it would only cover 7000 pounds.

My question is this, is it common practice in the trailer industry to install tires that are underrated for the stated weight rating of the trailer? I would think that such a company could be held liable in the event of an accident caused by the weak tires.

Those tires are NOT UNDERRATED since the TW is not carried by the axles and I bet those are 3500lb and with a min of 10 percent TW puts the max tire load in the neighborhood of 1700 per tire.

Now many as has already started in this discussion will talk about reserve capacity, etc., etc., but there are no agree to nor mandated numbers for reserve capacity so I guess one can pick anything out of the "GUESSTIMATE" hat on what they want to use. I can only say that now on two trailers starting back in 1982, that's not 35 years and close to 200K miles of actual towing my tires have always been loaded to which 200lbs of each tires max load and on my current trailer with over 60K miles it's down to around 50lbs for each tire and I have never had a blowout using the dreaded GY Marathon TT tires. I did recently have two failures, one a blowout and one a serious tread separation, but those were on some Kumho 857s that actually had like 200lbs per tire more load capacity than the Marathons they replaced. I believe that keeping the speed down, always watching your inflation and realizing that a serious pothole hit or curbing incident makes that tire no longer reliable and should it fail, it's probably not the tire but because of the damage done to it by the operator.

With all that said, if you can w/o jumping thru many hoops get a tire with 10 to 20 percent reserve capacity, that is obviously good, but does it really buy your anything ... I'm not convinced based on my fairly extensive personal experience.

Larry

As mentioned the difference between max TT weight and max tire rating is on the tongue. It is the same with the axels, my TT has a gross weight 7500 lbs. the two axels are only rated for 3500 lbs. each.

Million of "C" rated tire have been put on TTs every year for decades. They will continue to be put on TT for decades to come. They are used because they work for most TT applications. My C rated tires were rated 140 lbs. over the axel rating.

After 7 years and over 18,000 miles of towing with the original C rated tires I went to D rated tires, because it allows some latitude on tire pressure. My tires are rated C at 50 psi and rated D at 65psi. They are also several hundred lbs. over the axel rating at their D rated pressure.

So, when I was in Texas at 80 degrees and the tires were at 65 psi cold, I did not have to worry that three days later in Flagstaff waking up to 4 inches of snow and temps in the high 20's that my change in tire pressure would be an issue. Especially since two day later I was in Phoenix in the 90's.

A person certainly can and some do, spend the money to upgrade their tires. The RV industry and the majority of the RV owner will not. The same can be said for P rated tires on pick-ups.

It is basically the individuals choice.

205-15-C s/b 1820 rated for 7280 + 660 hitch weight = 7940

By all means when spending money get LRD for 2150 rating at 65 psi.
OEM tires are good maybe two seasons.

I recommend Goodyear Endurance or Maxxis M8008

legolas wrote:
Do not forget the effect of heat on the tires. I have load range C's, keep the pressure at the rated max, also I use a TPMS system to monitor pressure and temp...one other thing - when at all possible I do not exceed the max speed rating (62 mph)...this is important...and yet I see many folks ripping by me at speeds exceeding that some obviously at 70mph or better.

You have LRC ST tires rated for 62mph max? Are you sure???

If so, dump those pieces of junk and buy something with a speed rating over 65mph. The new Marathons and Carlisle HD's are good for well over 65mph in all sizes.

Don't sweat a higher load rating unless you're near over their weight spec.

Old-Biscuit wrote:
Tire Max Load Rating is same as or more then trailers axles.......

Remember-----
Trailer tongue weight is part of trailers GVWR BUT is not carried/supported by trailers axles/tires. Tongue weight goes on tow vehicle

SO YES tires are marginal but they cover the axle weight. Axles are probably rated at 3500# each for 7000# also.

Thanks for all of your responses. I had forgotten about the tongue weight. I will not intervene regarding his tires. I did tell him about the importance of keeping them pumped up and how heat will also be an issue. Of course driving fast creates more heat, so there you have it.

Thanks again.

Do not forget the effect of heat on the tires. I have load range C's, keep the pressure at the rated max, also I use a TPMS system to monitor pressure and temp...one other thing - when at all possible I do not exceed the max speed rating (62 mph)...this is important...and yet I see many folks ripping by me at speeds exceeding that some obviously at 70mph or better.

mark twain said it all.