What am I Missing?

[Azcougar]

My wife and I are new to the forum and as of last year new to 5th wheels. Been reading a lot about tires and loading which caused me to take a hard look at the numbers on our 2012 Cougar 280BHSWE. So, here's my question and what am I missing; our shipping weight is listed at 7742 lbs and the max cargo capacity is listed at 2468 lbs for a total of 10,210 lbs and yet the TowMax ST 225x75R15D tires show a max loading of 2340 lbs/tire or 9360 lbs total. If I'm figuring this out correctly I could be over the max tire limit by 850 lbs. The Discount Tire website recommends that you have a safety factor of 20% between your max tire rating and your GVWR. So, If correct I'm having a hard time believing that Keystone would ship a product where the margin of safety is this far out of the window; so what am I missing?? Also haven't seen much on the Carlisle tire that Discount Tire sells, would anyone out there have any thoughts? And Thanks in advance for the responses.....

[hankpage]

You have to remember that on a 5er 20% - 25% is on the pin. That still doesn't give you the margin suggested but lets manufacturers squeak by with bare minimums. JM2¢, Hank

[JRTJH]

Automotive and truck tires require a "safety margin" but ST tires for trailer use do not. So manufacturers can put tires on a 5000 lb axle with a rating of 2501 lbs each and be within the federal requirements. The "safety margin" doesnt apply.

The way manufacturers calculate GVW is by maximum weight MINUS pin weight. That leaves axle weight. Example: trailer GVW and actual loaded weight is 10,000 lbs, pin weight is 2,500 lbs, that leaves 7,500 lbs on the axles. There are two, each supporting 3,750 lbs. The manufacturer could do one of two things, install 5,000 lb axles, or theoretically the manufacturer can put 3700 lb axles under that 10,000 lbs GVW trailer by just reducing the GVW to 9,900 lbs.

That's called "pencil work" in my neck of the woods, but it saves the manufacturer the cost of stepping up to the next available axle which would be a 5,000 lb rated axle.

Usually, tire size on "factory" axles is standard, 205/75R/15C on 3500 lb axles, 225/75R/15D on 5000 lb axles, etc.

[Azcougar]

Thanks, only had trailers before, but still don't like the fact that Keystone or any manufacture runs so close to the edge especially when it concerns a possible safety issue; so this week going to upgrade the tires from the current D range to an E range. This should give me a comfortable margin of safety. BTW I wouldn't have been aware of this if it hadn't been for this forum, so thanks to all.....

[JRTJH]

225 75R 15 LR E tires are inflated to 80 PSI, so make sure the wheels on your axles are also rated to carry 80 PSI since the LR D tires are only inflated to 65 PSI. You should find the maximum load and the maximum inflation pressure stamped on the back of the wheel or possibly inside it on the rim flange. There's a possibility that you'll need to buy new wheels to safely install LR E tires on your rig......

[rhagfo]

if you get the E rated, you could be like me, four tires rated at 3,014# ea total 12,056# just about the GVWR for our 5er.

[chuck&gail]

As said above, CHECK RATINGS ON RIMS! No sense overloading rims, that sure isn't any safer than overloading tires!

[Fastback]

I recently installed new tires on my Laredo 27RK. I ended out using the D range tires since the rims are only rated at 2,500 lbs. I don't remember if the rim indicated max psi., but I'll check it out since I'm in the process of repainting the rims.

[IdahoSRT10]

My wife and I are new to the forum and as of last year new to 5th wheels. Been reading a lot about tires and loading which caused me to take a hard look at the numbers on our 2012 Cougar 280BHSWE. So, here's my question and what am I missing; our shipping weight is listed at 7742 lbs and the max cargo capacity is listed at 2468 lbs for a total of 10,210 lbs and yet the TowMax ST 225x75R15D tires show a max loading of 2340 lbs/tire or 9360 lbs total. If I'm figuring this out correctly I could be over the max tire limit by 850 lbs. The Discount Tire website recommends that you have a safety factor of 20% between your max tire rating and your GVWR. So, If correct I'm having a hard time believing that Keystone would ship a product where the margin of safety is this far out of the window; so what am I missing?? Also haven't seen much on the Carlisle tire that Discount Tire sells, would anyone out there have any thoughts? And Thanks in advance for the responses.....

Sell the OEM 15" wheels and tires soon to recoup your losses. I sold my 4 OEM wheels/tires for $350 on EBay, they are easy to ship as all UPS did was place a shipping sticker on each wheel.
I bought new 16" wheels and E" rated Maxxis tires $1000 total.

[adVentureMan]

My wife and I are new to the forum and as of last year new to 5th wheels. Been reading a lot about tires and loading which caused me to take a hard look at the numbers on our 2012 Cougar 280BHSWE. So, here's my question and what am I missing; our shipping weight is listed at 7742 lbs and the max cargo capacity is listed at 2468 lbs for a total of 10,210 lbs and yet the TowMax ST 225x75R15D tires show a max loading of 2340 lbs/tire or 9360 lbs total. If I'm figuring this out correctly I could be over the max tire limit by 850 lbs. The Discount Tire website recommends that you have a safety factor of 20% between your max tire rating and your GVWR. So, If correct I'm having a hard time believing that Keystone would ship a product where the margin of safety is this far out of the window; so what am I missing?? Also haven't seen much on the Carlisle tire that Discount Tire sells, would anyone out there have any thoughts? And Thanks in advance for the responses.....

If Carlisle tires were the only tires available, I'd park the rig and leave it parked. I had far too many problems with them to ever put a Carlisle tire on ANYTHING ever again.

[Jim W]

Hi, I would contact South West Wheels for your needs. This company has been recommended many of times on several Diesel Truck forums as being one of the best to work with for trailers.
I have attached their web page link, hope this help?
https://www.southwestwheel.com/store/c-45-15-assembly.aspx

Jim W.