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Old 07-23-2018, 02:40 AM   #41
ctbruce
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Originally Posted by ubetcha View Post
These numbers are starting to get confusing. Your quote of 3520 # would be for one axle correct? This campers has two axle's so that would give me a capacity of 7040# total. The listed GVWR is 7825#. Even with all these figures flying around, I think I would still be better off with LDRD or higher. Man I getting confused.�� The GVWR is a number I should not exceed ,which includes the trailer and cargo,right?
The pin holds the weight difference plus more.
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Old 07-23-2018, 12:55 PM   #42
CWtheMan
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Quote:
Originally Posted by ubetcha View Post
These numbers are starting to get confusing. Your quote of 3520 # would be for one axle correct? This campers has two axle's so that would give me a capacity of 7040# total. The listed GVWR is 7825#. Even with all these figures flying around, I think I would still be better off with LDRD or higher. Man I getting confused.�� The GVWR is a number I should not exceed ,which includes the trailer and cargo,right?
I was just trying to keep it simple.

When thinking tires for RV trailers you need to concentrate on their design, how they are selected and fitted by the trailer manufacturer.

Tires for our trailers are not required to provide anything more in load capacity than what the trailer manufacturer has certified the axles to carry. The axles on your trailer will have the vehicle manufacturer’s certified GAWR load capacities listed on the vehicle federal certification label. That label will be displayed externally with a tire & load label on the left hand or driver side of the trailer forward of the axles.

Here is how the math works. The total GAWR maximum loads, when added to the vehicle manufacturer’s recommended/published tongue weight MUST not be less than the trailer’s GVWR.

Another standard is worded sort of like this. The tires fitted to the trailer by the vehicle manufacturer must provide a load capacity that is an appropriate fitment in accordance with the vehicle manufacturer’s recommended cold inflation pressures.

Therein lies a very high percentage of early RV trailer tire failures, no load capacity reserves.

The current rules for our tires were approved by NHTSA and finalized in 2007. Many of the rules committee members recommended a 12-15% load capacity reserve be added to the trailer tire standards. They were not approved. The current track record for replacement tires with a higher load capacity than the OE tires, seems to support the fact that, RV trailer tires are in desperate need of excess load capacity.

From the information I found, your trailer has 3500# GAWR axles. The ST205/75R14D provides 2040# of load capacity @ 65 PSI, that’s more than 15% in load capacity reserves above the axles maximum load capacity. There are at least a half dozen ST tire manufacturer’s that build that sized tire with a LRD. One in the USA.

With the LRD tires being the same physical size and design as those listed on your certification label, the validity of the tire size on the certification label is not compromised. Why? Because both load ranges require the use of identical load inflation charts. In other words, the LRD will provide the identical load capacity of the LRC @ 50 PSI. Everything above the 50 PSI is optional and considered load capacity reserves.
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