Tire Margins on 2619

My understanding is that a 2619 ships with Goodyear Marathons ST215/75 R14 tires. That is the size tire on a 2619 that Custom RV brought by our house to try in the garage last weekend. They have a maximum rated load capacity of 1870 lbs at 50 PSI for a total of 3740 LBS. I was wondering if any one can tell me the actual weight on the axle of a fully loaded 2619 with A/C, two full propane tanks, two baterries, full of water and around a week's worth of camping gear. My guess is that there will not be too much margin, but I would be interested in someone who actually weighed their TrailManor.

On another post I thought I saw somene who stated their Trailmanor weighed 3700 lbs, but I don't remember the model number.

I was also wondering if a pair of 15" Goodyear Marathons ST 225/75 R15 could be mounted on a 2619. They have a capacity of 2150/tire at 50 PSI, allowing for some extra margin.

You'll be fine with the 14" Marathons on a 2619 as long as you are weight conscious when you pack the RV.  Put your heavy stuff in the tow vehicle and the bulky light stuff in the TM.

My experience is with a 2720 but I'm willing to bet that the 15" tires won't fit.

If you really feel you need more tire capacity you could look for 65 psi truck tires.  However, it has been pointed out that the rims and the axle are also rated around the limits of the present tires.

I sincerely believe that the Carlisle tires used had a manufacturing defect.  One of mine blew out under a relatively light load despite the best preventative maintainence.

Thanks for your advice.

I ordered a 2619 last Friday from Custom RV.  I ordered an extra spare.  We are planning to go to Alaska in the summer of 2005 and I thought that having two spares would be advantageous.

Goodyear Marathons seem to be more reliable than the Carlisle tires from discussions on this board.

I have an 01' 2619 with Goodyear Marathons. I too have some of the same questions about the weight ratings.

Having sold tires in my past life, I seem to recall that if we were to go to a 15" tire and wheel assy, we would have to also change out the break drum to a 12" diameter I believe.

My question is IF there are any other tire size choices available for Trailers? I know of Goodyear and Carlisle...

Anyone know if Michelin or Goodrich make any heavier duty trailer rated STR tires??? ???

Gregg

Goodyear 14" Marathons only come in load rating "C". They can take up to 50 PSI. There are no Marathon 14" tires available in a "D" rating which would allow a 65 PSI and would add some margin to the carrying capacity of the tires.

There are more choices in 15" tires.

[Bill]

OrangeKid - You're asking good questions, but perhaps the wrong ones.

Tipper's post is good. And review Denny A's FAQ on weight.

As Tipper notes, the Goodyear 14" Marathons are rated at 1870 pounds each. IF - and it's a big IF - the TM is loaded equally side-to-side, then the tires can support a total weight of 3740 pounds. RockyMtnRay has commented several times about the difficulty of loading equally side-to-side. The biggest problem is that the water tanks are all on one side, and water is heavy.

But please note! The axle can support only 3500 pounds. TIRES ARE NOT THE LIMITING FACTOR!

You can put 10,000 pound tractor tires on your TM, the axle will still limit you to 3500 pounds.

I weighed my 2720SL, ready for the road. At the moment it was weighed, that meant:

• No fresh water
• No gray water
• No black water
• Full propane
• Factory options: A/C, spare tire, awning, TV antenna.
• Clothes
• No food
• Microwave
• Tools

The TM was hooked to the tow vehicle, spring bars up in ready-to-travel position, so I was measuring the actual weight on the axles and tires.

The weight was 3340 pounds.

Road-ready weights up to 3700 pounds have, in fact, been reported. Scary. Pay attention to what and how you load. Sorry, but tricking out the tires won't get you around the limit.

Just my 2 cents worth.

Bill

If you fill your water tank (assuming 20 gallons) you will be at the weight limit of the axle and heavier on the drivers side. Fill the water heater and you have exceeded the limits. And you haven't even put anything in the refrigerator or the black and gray water tanks. What about people that have 40 gallon tanks? The manufacturer should not offer options that allow the weight limits of the trailer axle or tires to be exceeded.

One can even argue that a TM with a 20 to 40 gallon tank, black water tank, (gray water?) and refrigerator all on one side represents a poor engineering design. I puts an uneccessary burden on the owner to try to pack the TM so that the overall weight is equally distributed on both wheels of the trailer. It might be an impossible task.

Another observation. Several people on this board have reported blown tires; has anyone ever reported a failed axle? The information suggests that tires fail much more often than axles. I submit that tires are the limit.

I think the RV industry is where the automobile industry was 30 - 40 years ago when cars had tires and brakes that were inadequate to the task.

Thanks, I will check the FAQ that you recommended.

[Bill]

OrangeKid -

The information suggests that tires fail much more often than axles. I submit that tires are the limit.

There is a lot of truth in what you say. The failure of a tire is pretty obvious. By contrast, I don't know what the failure mechanism of an axle is. Maybe it just clunks down on the stops, and you lose the spring action. Maybe you can drive hundreds of miles without knowing anything has failed - until things start to shake apart because there are no working springs on the axle. Not good, but not immediately catastrophic, either. All I know is, I don't want to go there - it is sure to be expensive. However, it seems reasonable that the axle manufacturer puts a weight limit on the axle for a reason. The fact that I don't know the reason, doesn't mean the limit can be ignored.

The manufacturer should not offer options that allow the weight limits of the trailer axle or tires to be exceeded.

In this minor point, I have to disagree. The RV manufacturer can offer lots of options, and that is good. For example, if the owner is going to do a lot of dry camping, and he can opt for a 40-gallon water tank instead of a 20-gallon tank, that's a great thing. There can be a whole fleet of options, but it is up to the owner to understand that he can't have all the options at the same time. He should know that if he loads up his rig with 180 extra pounds of water, then he better unload 180 pounds of something else.

The problem is that manufacturers don't make this information readily available to the owners. The owners don't know that these trades have to be made. As a result, it is easy to overload an RV, without even realizing it.

The weight rating methods for RVs - all of them, not just TMs - are a peeve of mine. I don't like the way things are done, and I admit it. But whether we like it or not, the burden of knowing the actual loaded weight comes down on the owner, and frankly, I think the owner ought to be knowledgable enough to deal with it. An RV is not a little red wagon, it is a complex machine.

And that is one of the values of a forum like this - someone on the forum knows these obscure things.

Bill

I guess we will have to agree to disagree. The RV manufacturer can easily configure a computer program to make sure that a particular combination of options will not be suitable because of exceeding rated weight limits (or any other limits) on axles and tires. An analogy to this is the Dell web site. It will not allow one to configure a computer with incompatible components. If Dell can do it why can't TM? For example, if a TM is designed to offer 1000 lbs carrying capacity the computer program could automatically tell the manufacturng line of the need for upgraded axles and tires due to options selected. I understand that in the automobile industry the springs on cars and trucks are customized based on each vehicle's weight. Why can't the same be done in the RV industry?

I personally have never heard of an axle failing and I assume it is a very rare event. Maybe axles have much higher safety margins than tires. My guess is that many RVs are overloaded; some of them grossly. We always hear of tire failures. How many people check their air pressure often enough to make sure that the full rated carrying capacity of the tire is available?

Yes, the owner has the responsiblity to make sure that his RV is not overloaded but the RV industry has a responsibility to make sure that RVs have enough carrying capacity so that RVrs can carry all the paraphernalia they normally do in the real world.

Yes, one thing we can agree it on. This is a great forum.

[Denny_A]

I know that it is akin to committing hari-kari (sic) to jump in here - but, like a moth to the............ :P

Regarding axle and options and max weight limits, etc. Let's assume we're hauling a 2002 2720 SL. Using numbers from TM's specs, we know that:

Approx dry Wt -------- 2680 lbs
Approx Tongue Wt -- 378 lbs (2680 * 14.1%)
Approx Load Cap ----- 1394 lbs
Approx Max Gross Wt - 4074 lbs.
Max Recommended Tongue WT -- 14.1% of Max Gross = 574 lbs.

Here's the kicker. If the max allowable tongue weight is carried on the hitch WITHOUT use of weight distribution, then the load on the axle is 4074 lbs - 574 lbs = 3500 lbs. Why, it's almost like magic how that works out.

BTW, I know the tongue weight % numbers to be correct, since they came from THE TrailManor design engineer - directly in a one-on-one dialog.

Problem (as usual): If one employs a WDH (who doesn't), then some of the tongue weight is distributed back to the axle. If the set up is done properly, it will be about 1/3 of the total. So, in the 574 lb example, about 190 lbs is pushed back to the trailer - therefore onto the axle.

At this point the axle is carrying 3500 + 190 = 3690 lbs. OOPS! What's a poor owner to do.

1. Limit MGW of the trailer to 4074 - 190 = 3884 lbs. -OR-
2. Don't worry about it and just have fun.

Regarding 2, a few details regarding axle wt limits are in order. There are already several posts in this forum's archives regarding the subject.

Essentially it comes down to a difference in point of view between Dexter (axle mfr.) and TrailManor.

Dexter say that the axle is limited to 3500 lbs as evidenced by weights recorded with the tires resting on scales.

TrailManor say that, in reality, the axle and wheel assemblies, taken together, are unsprung weight, amounting to 200 lbs. Therefore, if the scale shows 3700 lbs, the axle capacity of 3500 lbs is not exceeded. You're good to go.

I neither disagree nor agree with the TM method. I do know the above interpretation of TM's position is correct, since it was communicated to me aurally by the design engineer and repeated at my request. Therefore, I am acting as a messenger, not an advocate.

Regarding 2., above, one could carry 4074 lbs whilst using a WDH, record trailer weight minus hitch load as 3700 lbs and be good to go - according to TrailManor. However, using the Dexter approach, unload 200 lbs from the axle, to be really safe.

Summary: 1. Dexter -- 3500 lbs max weight on the tires
2. TrailManor - 3700 lbs max weight on the tires.

I'll stick with the Dexter model, just to be SAFE!

Denny_A