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Old 11-05-2015, 08:28 PM   #111
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G, have you considered a tire loading event caused by hitting a bump or hole? The load could be or would be huge, if only for a brief period of time. Also, when the manufacturer tests tires and posts a limit on weight, how does that work? Do they run the tire with increasing heavier weights until failure? Or, how do they come up with these numbers?

I've noticed many people take their GVW and divide by 4 (or 2) and don't consider the weight carried on the tongue (by the tow vehicle).
WW
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Old 11-05-2015, 10:25 PM   #112
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G, have you considered a tire loading event caused by hitting a bump or hole? The load could be or would be huge, if only for a brief period of time. Also, when the manufacturer tests tires and posts a limit on weight, how does that work? Do they run the tire with increasing heavier weights until failure? Or, how do they come up with these numbers?

I've noticed many people take their GVW and divide by 4 (or 2) and don't consider the weight carried on the tongue (by the tow vehicle).
WW
Good questions. I'm still researching and learning, and don't know the answers. Each time I peel back a layer of understanding, there's another layer of complexity under it....like potholes.

I don't know how the standard testing is done, but would love to learn. I was told the tire manufacturers don't test for the kind of overload on curves that I've been considering. And for crosswind overloads that can be pretty much constant, I would think the standard load rating should apply. But certainly they must do something to verify or quantify rock and pothole resistance....I would hope.

Maybe Tireman knows how the testing is done and will pipe up and educate us.

I do see that Michelin has a 'pothole resistant tire'....the XM2. The implication is that you don't get extra pothole resistance unless you pay for it.

I agree that to get static load on the tires one needs to take the trailer weight and subtract the tongue weight; I've been doing that in my calculations. But even this may be too simplistic. If you have an equalizing hitch, it'll take some of the weight off the back of the truck and move it to the front of the truck and to the back of the trailer. So of the weight that you pass off to the truck via the hitch, some of it comes back to the trailer from the spring bars on the hitch. Rather than try to figure this all out to get an accurate answer, maybe it's better to just hitch up and weigh the trailer with the truck attached but off the scale. Better yet, have each wheel weighed individually since there will be variation among them and it's the one with the heaviest load that we should worry most about. (I plan to do this first chance I get.)
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Old 11-05-2015, 11:23 PM   #113
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There are Federal regulatory tests that all tires are suppose to be able to pass. Each "Type" P or LT or ST or Truck-Metric have different tests and procedures.

I will did out some posts that cover the testing in detail but in general there are no standard "pot-hole" tests.

Loads have bees set for years by type and inflation level.

RE "take their GVW and divide by 4 (or 2)" is definitely not the correct way to estimate your tire loading. There is a mountain of data showing that axle to axle the split is not 50/50 but could be as bad as 45/55 and same for side to side on a single axle with almost no RV being exactly 50/50.

In general I suggest that until you get actual tire loading you assume an imbalance of at least 47/53 to 45/55%

I have many posts on my blog on tire loading and how to learn the actual weight on a tire. Simply select the tag "weight" on lower left of a blog page.
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Old 11-06-2015, 08:54 AM   #114
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There are Federal regulatory tests that all tires are suppose to be able to pass. Each "Type" P or LT or ST or Truck-Metric have different tests and procedures.

I will did out some posts that cover the testing in detail but in general there are no standard "pot-hole" tests.

Loads have bees set for years by type and inflation level.

RE "take their GVW and divide by 4 (or 2)" is definitely not the correct way to estimate your tire loading. There is a mountain of data showing that axle to axle the split is not 50/50 but could be as bad as 45/55 and same for side to side on a single axle with almost no RV being exactly 50/50.

In general I suggest that until you get actual tire loading you assume an imbalance of at least 47/53 to 45/55%

I have many posts on my blog on tire loading and how to learn the actual weight on a tire. Simply select the tag "weight" on lower left of a blog page.
I've considered or at least wondered about the ratings; and wondered the margin before failure. Not only side to side imbalance, but axle to axle. I haven't gotten individual wheel weights but have weighed axles on the trailer and truck; with and without WDH. I would love to be able to weigh each wheel.

I have always hoped (for lack of a better word) that normal loads experienced while on the road (moderate bumps, sway, cornering, side winds) are considered in the tires ratings, but imbalanced loads, under-inflation, potholes, and other road hazards is on us the user. Dunno.

I'll check out your tag. Thanks.
WW
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Old 11-06-2015, 09:03 AM   #115
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There is a mountain of data showing that axle to axle the split is not 50/50 but could be as bad as 45/55 and same for side to side on a single axle with almost no RV being exactly 50/50.

In general I suggest that until you get actual tire loading you assume an imbalance of at least 47/53 to 45/55%.
So true and consideration of how level the camper is so as not to throw to much of the load on one axle and its tires compared to the other and how the things that are kept inside are dispersed as to not load to much on one side.
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Old 11-08-2015, 11:05 AM   #116
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So true and consideration of how level the camper is so as not to throw to much of the load on one axle and its tires compared to the other and how the things that are kept inside are dispersed as to not load to much on one side.
...and even if loading of the trailer were perfectly balanced (which ain't gonna happen) the axles themselves aren't perfectly matched.

The springiness of my Torflex axles comes from rubber, not a calibrated metal spring. I talked to a Dexter engineer who agreed that there's likely to be as much as a 10% force variation wheel to wheel just because the half-axles of an independent suspension aren't perfectly identical.
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Old 11-08-2015, 12:10 PM   #117
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Sounds like a mute point. Am I stuck with going to go with what the manufacturer installed with the build ? Seems to me that corners were and are cut to keep price down, mine came with 6k axles and should have been 7k. Tires and rims at or near max weight of trailer empty. Might work out for awhile due to minimal use or nearby (local) weekend camping and then seems like when there is an issue, you're out past the warranty time frame. In my opinion there should be recalls to fix the issue. To me it seems like for my own peace of mind and for the safety of me, my family and anyone traveling down the road near me then I will have to upgrade to bigger axles, rims and tires on my own.
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Old 11-08-2015, 12:45 PM   #118
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Yeah.
I agree that a recall appears to be justifiable.


I think we all had a reasonable expectation that our trailers were safe to use in ordinary situations without overloading of safety components like tires, wheels and axles. Yet this appears to not be the case.


It'll be interesting to hear back from the NHTSA on this. They're still chewing on the math I gave them. If it were blatantly wrong, I would think they would have gotten back to me relatively quickly. When I hear back, I'll publish the response here.
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Old 11-08-2015, 01:00 PM   #119
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BTW, I filed a complaint with the BBB in Fort Wayne against Forest River. I asked that they reimburse me for the value of the factory tires on my trailer since they're useless to me. I have provided my math as part of the complaint, so Forest River can't deny that they're aware of the problem. They went silent after simply saying that I've been 'instructed' that the factory tires are suitable for my trailer, and after I challenged them to show me what's wrong with the math. This issue hasn't closed as of today.
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Old 11-08-2015, 01:03 PM   #120
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BTW, I filed a complaint with the BBB in Fort Wayne against Forest River. I asked that they reimburse me for the value of the factory tires on my trailer since they're useless to me. I have provided my math as part of the complaint, so Forest River can't deny that they're aware of the problem. They went silent after simply saying that I've been 'instructed' that the factory tires are suitable for my trailer, and after I challenged them to show me what's wrong with the math. This issue hasn't closed as of today.
Yes, I have had a complaint with Forest River on my axles. Their response was that they would sell me the 7k axles at their cost.
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