Community Forums

myredracer · 07-12-2013, 12:18 AM

We have Freestar offshore tires on our near new TT, 205 series in 15". From what I gather from reading around, load range C tires are by definition 6 ply tires? Our tires are only 5 ply though. What does this mean? Is there really a 5 ply load range C or have we got a lower quality tire? Says load capacity is 1820 lbs. No "Ch*na bomb" remarks please.....

Skip426 · 07-12-2013, 10:42 PM

The 6 ply RATING is a throw back to bias ply tires, when every extra ply increased the load capacity of the tire. Radial tire load range C and the 1820 lbs. capacity are the new load capacity rating and yes that rating can be achieved with a 5 ply sidewall/tread combination.
If the 1820 lbs. capacity X4 is equal to the trailer GVWR you should be OK.

myredracer · 07-12-2013, 11:48 PM

Thanks! Looks like I did not understand the terms on the tire. It says 5 ply tread, 2 polyester + 2 steel + 1 nylon. It also says 6PR Load Range C. I guess there is a 6th inner ply?

Am a little concerned about the 7280 lbs total tire capacity since our GVWR is 6800 and the actual TT weight is 6600 lbs with just a rather ordinary cargo of things for a short camping trip. Not a lot of comfort margin. It would so easy to overload this trailer. Just a tank of fresh water would do it, and all 4 tanks would be more than 1,000 lbs over the GVWR. We are planning to upgrade to load range D tires at a minimum. Not at all impressed that they would design a TT like this.

Skip426 · 07-13-2013, 12:13 AM

Situation is all to common, they figure you'll be carrying 750lbs+ of the GVWR, on the truck via the hitch. Axle rating is something else to check.
When I was shopping for a class A, I was shown a coach with a 518 lbs. CCC. DW, myself and a saleslady standing in the coach and it was overloaded. Granite counter tops , tile floor, hardwood everywhere, beautiful but overloaded from the factory. Traded off 18 months 7,000kms. after purchase , probably because of handling issues.
Educate yourself , as far as weights are concerned , know what you need for capacities , because salespersons , don't know or won't tell you.

There isn't an extra ply the newer tire is RATED with 5 ply to, carry the same weight, as an older tire with 6.

Ray,IN · 07-13-2013, 07:56 PM

myredracer, you may upgrade to load range E, F, or G 15" ST tires if you wish, for the comfort margin. I would not do so though, those tires are so stiff everything inside the trailer will take a beating. Load range D will be a better choice, for both ride and price.

JIMNLIN · 07-13-2013, 08:12 PM

Our LT and ST tires are a two ply carcass with additional plies on the tread. Some LT E tires advertise a 3 ply carcass (sidewall) but their no stronger than a two ply E tire.
Also the XPS Rib and the Bridgestone R250 both area all steel ply carcass tire with just one ply sidewall. One strong steel ply sidewall and is very cool operating even at max loads.
Your tire has 2 body plies (carcass) and 2 steel and 1 nylon cap under the tread. This is typical for a 6 ply rated tire.

Your trailer weighs 6600 lbs. Now 600 lbs approx is on the tow vehicle which leaves 6000 lbs approx on 4 tires. The math say your trailer needs a tire with a minimum of 1500 lbs per tire. Your ST205/75-15 C has a 1820 lb capacity. Tire experts tell us a 15-20 percent reserve capacity is best when using a ST tire. Your tires have a 20 percent reserve.

Tirerack.com ply rating info;
Today's load range/ply ratings do not count the actual number of body ply layers found inside the tire, but indicate an equivalent strength based on early bias ply tires. Most radial passenger tires have one or two body plies, and light truck tires, even those with heavy duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric body plies, or one steel ply.

myredracer · 07-14-2013, 03:39 AM

Some good points and info., thanks!. Our axles are 2 x 3500 lbs and as JIMLIN says, we have about 6,000 actual weight on the axles so they are okay as far as the rating goes paper. But there is more to our story below.

Yes, the tires would appear to have 20% reserve capacity which sounds good. We are not planning to do any dry camping as we have a campground membership and are hooked in the RPI, C-C, etc. network. But, some owners with the same trailer could tow with one or more full tanks in which case the tires would be at capacity. I think many believe their trailers should be fine with full tanks. If someone wanted to add more cargo for a long trip, weight would go up, but since I know that we only have 200 lbs of CCC left, we won't do that and would have to go in the truck which has lots of spare cargo cap. But some owners out there will think they can up to 1563 lbs as the published NCC states. The numbers look good on paper until you go weigh the trailer at a scale. None of the options we ordered are included in the UVW of 5237 lbs and they aren't deducted from the NCC.

I thought in order to upgrade to "E" or higher rated tires you need to have rims rated for the higher pressure? We have optional alloy rims and don't know if they can take the higher pressure. Our dealer couldn't even tell me what the advantage of their optional Marathon tires is and did not know the rim width.

We've had serious issues with frame strength on our brand new trailer. It was inspected by a government certified inspection facility and found to have "extreme flex". The spring hangers bend one way or the other depending on lateral force applied, as in turning corners, from sway while towing or lane changing while towing. As a result, the camber on each wheel is constantly changing and is detrimental to tire wear. If not dealt with, the basic C tires would take a beating and not last long I think because of the flex. Back to the axle ratings, with all the spring hanger flex and movement, I suspect the axles will eventually become damaged. Long story on all the frame issues. The TT manufacturer has said they will rectify it but have yet to have details confirmed. The frame needs to be stronger and the GVWR needs to be raised so it's not running at or near the GVWR and so that it has more useable CCC. If this is what they end up doing, then we will have at least load range D tires anyway (I *think*) and I think the axles will go up to 4,000 lbs. It's a very unusual situation to be in. Have been on a very steep learning curve on frame strength, component ratings and various weights as a result. Can't believe some of the things I am finding out and my head is still spinning. All I want to do is go camping...

Here is a link to a photobucket photo of the wheels at the frame shop with lateral torque applied. (need to stop and take time to figure out why I can't embed a photo)

http://s594.photobucket.com/user/zip...tml?sort=3&o=9

I'm raising our frame problems also in part because there will be other owners with the same or similar frame and weight issues. Instead of waiting for their tires to fail, they might want to look closely at their frames. Their C rated tires may look good on paper, but they are going to take a beating with all the frame flex IMHO.

It also just occurred to me that the tires already have over 2,000 miles on them from delivery from the plant to the dealer on the west coast and are thus substantially used before we even got the trailer. Have never read about anyone bringing this up before.

There are so many comments flying around about Chinese bombs regardless of what brand they are it's not easy to separate the wheat from the chaff. Other than driving under 65 mph and doing all the other things to take care of your tires, the best thing to do to avoid chances of premature tire failure seems to be to go to LT tires if you can, but otherwise go with the highest load range you can find or afford and buy what you think is the highest quality.

Skip426 · 07-14-2013, 11:37 PM

Gil, your catching up fast on what to look for when purchasing an RV, of any description. An awful lot are underbuilt and overrated, gussied up and the basic structure is ignored. Very few manufacturers can be trusted to give you good info as far a weights are concerned.
Best I've seen was my current Newmar , base unit CCC was 5,000lbs, options reduced mine to 3753lbs. the info sheet gave the weight of every option, right down to the CB radio prep package at 1lb. But even then there was a recall to replace the front tires that were overloaded.
So extreme diligence on the buyers part is the order of the day.