Is there a "Recommended" 15 inch tire now

[Wavery]

Originally Posted by Al-n-Sue

I don't know that I've seen this specifically noted anywhere, but it seems to me that the load rating of the 14" Marathon's was just marginal for a 2720. Could that explain the seemingly large number of blowouts on that model/tire size? If you load up a 2720 (or even a 2619) it could put the total weight over the limit. And even a properly inflated tire at reasonable speed would be subject to failure. And it might explain the relative lack of blowouts on 3023 and 3124 models - which have a D rated 15" tire from the factory?

I don't have the figures handy here, but I know that the D load range for a 15" tire is >2600 lbs - which puts the total way over 5000 lbs for the trailer. You'd have to load up a 3124 pretty heavy to reach that. (My 3124 is 4240 lbs with close to camping ready status).

Just a thought. Other may have differing opinions.
Alan

Don't forget.....the WDH will add weight to the tires as soon as you hook-up (adding probably 200# to that 4240) and when you go over bumps and dips that is further exacerbated by transferring load from the rear of the TV to the trailer axle (maybe as much as 500-1000# of shock loading). This is no small matter and must be considered when using a WDH on any trailer. I firmly believe that is a contributing factor to the # of blow-outs that we are seeing on these TMs...........

[TREXHUNTERS]

Thanks for the replys.

Yes, I had what I would consider a blow out on 15" load range D Marathons therefore I'm a little worried about getting those again. Of course having a defective valve stem on the spare which left my family stranded was pretty much the coup de grace for me for Marathons.

It sounds like there have been less frequent occurrences of the issues on the 15 inchers on TMs. Does anyone know if these type of seemingly systematic problems have been seen on other types of trailer/campers?

Lastly what are the choices. Marathons, Maxxis, Kumhos, Carlyles? others.

thanks

[Wavery]

Originally Posted by TREXHUNTERS

Thanks for the replys.

Yes, I had what I would consider a blow out on 15" load range D Marathons therefore I'm a little worried about getting those again. Of course having a defective valve stem on the spare which left my family stranded was pretty much the coup de grace for me for Marathons.

It sounds like there have been less frequent occurrences of the issues on the 15 inchers on TMs. Does anyone know if these type of seemingly systematic problems have been seen on other types of trailer/campers?

Lastly what are the choices. Marathons, Maxxis, Kumhos, Carlyles? others.

thanks

Your distaste for Marathon's based on the valve stem failure may be unwarranted. The valve stem has no effect on the quality of the tire. Failure of the valve stem will damage any tire.......

If the valve stem on the spare was bad, there's a good chance that the stem on the tire that blew may have failed, causing the tire to loose air and blow-out.

We recommend the use of all steel valve stems for that reason. It is my understanding that the valve stems that were used on the 2008 TM were recalled. I'm not sure how that recall worked or who was responsible for notifying who. There have been reports of a recall on this forum though. The recalled valve stems (which may or may not have included yours) were made in China and many reports like your developed early on.

[Bill]

Alan -

Quick question. You say that your 3124 weighs 4240 pounds in near-ready condition. Is that the total weight of the trailer (including tongue weight), or just the weight on wheels after the tongue weight is resting on the tow vehicle?

I'm thinking that 4240, being a fairly high number, is probably the total weight of the trailer. If so, about 15% of this (about 600 pounds) will be tongue weight. If you drop the tongue on the hitchball, but before you crank up the springbars, the tow vehicle would take all of the 600 pounds, and you would be left with about 3600 pounds on the wheels. If you then cranked up the springbars, about 200 pounds of the hitch weight would be transferred back to the trailer wheels, bringing the total to 3800 pounds on the wheels. In other words, the WDH doesn't add to the 4240 total weight, but instead moves 400 pounds to the tow vehicle. Of course, if 4240 does not include the tongue weight, the answer is different.

Wayne -

I'm interested in your theory of shock loading caused by a WDH. It is the springbars that transfer the weight, and the springbars are, well, springy. They are springy specifically so that they will keep a more-or-less constant force on the hitch as the geometry changes over a reasonable range of motion. If the bars were rigid, I would agree with you. And of course if you set up too big an angle between the tow vehicle and the trailer, exceeding the springbar's intended range of motion, then bad things could happen. But I'm not sure I'm buying the idea of a big shock load cuased by normal operation.

Do you have an authoritative reference for the theory of shock loading? Especially for the 1000 pound number?

Bill

[Wavery]

Originally Posted by Bill

Alan -



Wayne -

I'm interested in your theory of shock loading caused by a WDH. It is the springbars that transfer the weight, and the springbars are, well, springy. They are springy specifically so that they will keep a more-or-less constant force on the hitch as the geometry changes over a reasonable range of motion. If the bars were rigid, I would agree with you. And of course if you set up too big an angle between the tow vehicle and the trailer, exceeding the springbar's intended range of motion, then bad things could happen. But I'm not sure I'm buying the idea of a big shock load cuased by normal operation.

Do you have an authoritative reference for the theory of shock loading? Especially for the 1000 pound number?

Bill

I don't have one at hand but when I purchased my EZ-Lift WDH, the manual said to be sure to consider the amount of extra weight added to the TV rear axle when deciding on what WDH to buy. I did that and decided on a 1000# WDH (which I later regretted....sorta).

I noticed that when we towed with a lot of firewood, 2, generators and all the crap (can I say "crap" ?) the ride would be much more comfortable in the TV, especially going over bumps and dips. When I did not have as much weight in the back of the truck, I could feel a stiffer ride. It got me to thinking that the hitch was more in it's element with the heavier load and that the weight was being distributed through the flexing of the spring bars. This leads me to conclude that a portion of the weight and shock-loading from the spring bars is being distributed to the trailer axle. No real scientific research, just casual observation.

If you think of the rear tires on the TV with say.....500# of cargo in the back of the truck and no trailer attached. As you drive down the road, if you were to watch the rear tires as you go over dips, you would see the sidewall flex from the shock-loading. If you take the truck down the same road with a trailer and 600# of tongue weight added to the already 500# of cargo (no WDH), you would see that the tires are experiencing a corresponding amount of shock-loading. Now....add the WDH. As the vehicle goes down that same road, I think that you would see a great deal less shock-loading on the rear tires of the truck and that shock-loading would be distributed to the front axle of the TV and the trailer axle fairly evenly.

I suppose that I could sit down with a calculator and tape measure and work the #s out but I can't even begin to tell you how that idea bores me...... Just thinking about the #s though, 1K# would be pretty extreme, even for shock-loading. Just remember though, shock-loading can be quite extreme under certain conditions and can actually be many multiples of the dead weight load.

If you take a 16# bowling ball and drop it from a height of say 100', it will hit the ground with a shock load of several hundred pounds. The same is true when weighing a load on a tire standing still on a scale and the actual shock loading on that tire under operating conditions @ 65mph. When you add additional weight from the WDH, the shock-loading from the additional weight must be multiplied at the same rate.

To answer your question though.....no, I haven't really researched it because I don't use a WDH any longer. If/when I get a heavier trailer or a TT, I may be forced to do so.

[Harry Womack]

I have purchased 12 Maxxis tires on 3 trailers. I have not had any problems with any of them. I would use the load range E on the 3124KB. I use them with 65 to 70 PSI and they look normal. The load range D Marathons always looked like they were low at 65PSI.

[TREXHUNTERS]

A couple of more questions/comments.

Where is the thread/information for the "Great Tire Experiment"? I couldn't find it doing a search.

Wayne, Regarding the WDH; Are you saying that in affect the coupling of the two chasis' together through the WDH can actually transfer weight back to the camper frame from the truck? If so, does this happen in a steady state or just when you hit a bump or uneven surface?

I'm kind of leaning toward the load E Maxxis. They are hard to find though. Maybe that's why there seem to be so few problems with them.

And oh my is this a big subject on every trailer forum you research apparently with no "clear" solution. egads!

[Wavery]

Originally Posted by TREXHUNTERS

A couple of more questions/comments.

Where is the thread/information for the "Great Tire Experiment"? I couldn't find it doing a search.

Wayne, Regarding the WDH; Are you saying that in affect the coupling of the two chasis' together through the WDH can actually transfer weight back to the camper frame from the truck? If so, does this happen in a steady state or just when you hit a bump or uneven surface?

I'm kind of leaning toward the load E Maxxis. They are hard to find though. Maybe that's why there seem to be so few problems with them.

And oh my is this a big subject on every trailer forum you research apparently with no "clear" solution. egads!

The WDH transfers a portion of the trailer tongue weight to the front wheels of the tow vehicle and a portion to the trailer axle to remove weight from the tow vehicle rear axle. When static (parked) the theory works great. It also works well while the vehicle is in motion, particularly while braking.

Under ALL conditions the WDH adds weight to the trailer axle, so the answer to your question is a definite "Yes".

While the vehicle is going down the road there is ALWAYS shock loading on a vehicles tires while traveling on an uneven surface. It is my contention that the shock loading is less on the tow vehicles rear axle than it is on the tow vehicles front axle and the trailer axle. Thus, the WDH is transferring shock-loading from the center, outwards.

Let's say, for example, that we installed a 10,000# rated WDH instead of having lower rated spring bars involved in our normal set-ups. This would make the TV and trailer frame extremely rigid, like being all one piece. It now becomes clear that when you drive down an uneven surface (dips in the road), that the TV rear axle could actually be suspended in the air at times. During those times, all of the TV rear axle weight and shock loading would be transferred to the TV front axle and the trailer axle.

The only real difference that you have with the WDH is that the loading is maximized by the capacity of the spring bars. If one were to over-load the spring bars, they can (and do) actually bend from the process of transferring more load than they are rated for.

If I were to put a WDH rated @ 600# on my rig, I have little doubt that I would bend the spring bars. Not while sitting still but probably after hitting a few dips in the road. That's because the weight being transferred fore and aft would exceed 600# when hitting dips in the road. The more cargo that is in the rear of the TV, the more extreme this type of loading becomes.

I had a 1000# rated WDH on my TM and I felt that the risk of exceeding the TM tire weight rating was far greater than maxing out my WDH spring bars. After doing some backward processing on that, I came to the conclusion that there may be some possibility that WDHs may be contributing to the high volume of tire failure that we see on these rigs because the stock tires may not be able to withstand the added stresses from the WDH because they are too close to maxed out while static..

[TREXHUNTERS]

Thanks for the wdh explanation harveyrv. It makes sense.

It also makes me more comfortable that I should get load E tires for some margin. I think I need the WDH based on towing with and without it.

Bill - sorry for the delay - I didn't see your post until today.
Yes, the 4240 is the total weight of the trailer. I weighed the entire rig on the scale, dropped the trailer then weighed my TV. The difference is the weight of the trailer. At this time the trailer had fairly full propane tanks, batteries, and our "permanent" camping gear. But no water, no clothes, no food.