Am I calculating this correctly?

[Don_Z]

Over the weekend, I went to a local RV show and walked through 3 floor plans from Grand Design RV, makers of Solitude 5th wheels. I noticed they were equipped with LT235/85R16 tires.

They didn't have any brochures about their units so I went online after returning home. The 2 larger trailers (both listed as 38'11") are equipped with 7K axles. GVWR for these trailers is 16K, hitch weight is listed at 2600 pounds.

Gross weight 16K - hitch weight 2600 leaves 13,400 for the tires to support, but E load range tires would max out at 12,168. So...is this unit set up for tire failure right off of the assembly line?

Don Z.

[Me_Again]

Atom Ant wrote:
I haven't seen a manufacturer install LT LRE tires for years. This would be a new thing.

They are to expensive for their bean counters to order, the same as not wanting to install Goodyear G614's on trailers screaming for them.

Many manufacturers will use the same ST235/80R16E on the smaller 5200 or 6K axle units, as they buy in large lots. Only issue for them is 6 or 8 lug wheels. Probably split the order between the wheels, all with the same tire!

I challenged the head of NuWa a few years ago to install XPS RIBs instead of Uniroyal Laredo's and he said his people could not get Michelin to deal on low prices for the Ribs!

Trailer tires are picked by most trailer manufacturers based on price!!

Chris

[Atom_Ant]

I haven't seen a manufacturer install LT LRE tires for years. This would be a new thing.

[Me_Again]

2008Wildcat wrote:
They are Westlake St tires, rated at 3520 lbs @ 80psi.....

Take into consideration the dry pin weight and you have plenty of coverage.

And you should plan on either replacing those tires fairly soon or you will be experiencing a failure. This is yet another manufacturer providing the bare minimum tires to get it to the dealers lot and into your hands. There is the deal on Westlake.

Private Brand---Tire Seller------------------Tire Maker
Westlake---------Foreign Tire Sales------Various off-shore

Westlake tires are import by a company called Foreign Tire Sales and come from various different off-shore plants! Quality can vary depending on the plant of the week/month/year that produces the tires.

Look at this Westlake ST 14 ply rated: Westlake LRG 14 ply This tire is rated to 4080 pounds single for $165. What do they know that Goodyear fails to know about their G614 rated to 3750. What did P.T. Barnum say? Google Westlake ST tire problems for many mixed reviews.

If they have an option for LRG tires and you are ordering one, then spend whatever they want for that upgrade. There will not be a cheaper time to do it.

If you decide that you will upgrade right after purchasing it yourself, make sure the OEM wheels are rated to 3750 and 110 inflation or you will also be footing the bill for upgraded rims.

Regarding 2008Wildcats "you have plenty of coverage", I would not say that 40 lbs per axle(7000lbs) extra is plenty of coverage. A small in-balance left to right would overload a tire beyond its rating. Tire people like Carpriracer, Tireman9 and Fasteagle say that you should have 15 percent or so extra capacity. 40 lbs of excess capacity on a 7K axle is 0.6 percent!!!

This is just all common sense. You get what you pay for. Trailer manufacturers are buying these tires and wheels for next to nothing. They probably pay around a 100 dollars for an 16" aluminum wheel and LRE ST tire pre mounted from Tredit or Tireco buying truck or train car loads at a time. The get the frames in without tires and wheels, in stacks of 3-5.

Pressure from brand user groups giving feedback to their trailer manufacture is been becoming more effective with more and more manufacturers offering factory upgrades to LRG tires and switching all wheel purchases to wheels rated to 3750 and 110 inflation. Our Cardinal group leader does regular visits to the Cardinal factory and Cardinal sends people to our rallies, bringing new models for viewing. All trailers now have the upgrade wheels and the option for LRG tires is available.

We can fix this issue! Just say no to cheap tires!

Chris

[2008Wildcat]

They are Westlake St tires, rated at 3520 lbs @ 80psi.....

Take into consideration the dry pin weight and you have plenty of coverage.

[Blackcell]

Same here. My Carriage has E rated tires at 3500 lbs per tire and my Toyo's are E rated at 3750 lbs.

[720Deere]

The E rated tires that came on my Fuzion are rated at 3500 lbs per tire. Not all E tires are created equally! 3042 lbs is not a universal number for every E tire. The 275/65/20 E rated tires that came on my truck were rated 3750 lbs.

[mpierce]

Don Z wrote:

mpierce wrote:
Remember to subtract the weight that goes on the 5th wheel. And, probably G tires, not E. I see you did not show Load Range in your post.

Read again...I stated E Load Range in my post. The tires were definitely E Load Range. Their web site even states E Load in the specs.

Solitude Specifications

Don Z.

Here is your post"

Over the weekend, I went to a local RV show and walked through 3 floor plans from Grand Design RV, makers of Solitude 5th wheels. I noticed they were equipped with LT235/85R16 tires.

They didn't have any brochures about their units so I went online after returning home. The 2 larger trailers (both listed as 38'11") are equipped with 7K axles. GVWR for these trailers is 16K, hitch weight is listed at 2600 pounds.

Gross weight 16K - hitch weight 2600 leaves 13,400 for the tires to support, but E load range tires would max out at 12,168. So...is this unit set up for tire failure right off of the assembly line?

Don Z.



You mention Load Range E, but do NOT say that is what is on the trailer. Reading other posts, sounds like they did not get it either.

Anyway, sounds like too light a tire.

[fj12ryder]

Those on the floor could not have been LT tires, they simply aren't rated high enough. Two 3,000 lb. rated tires on a 7,000 lb. rated axle? I don't think so. I'm sure the tires specced on the product sheet you posted a link to are ST tires, and if you check the placard on the trailer you'll probably find they have de-rated the axles to 6,800 lbs.

Two G-rated LT tires will work but not two E-rated LT tires.

[Don_Z]

mpierce wrote:
Remember to subtract the weight that goes on the 5th wheel. And, probably G tires, not E. I see you did not show Load Range in your post.

Read again...I stated E Load Range in my post. The tires were definitely E Load Range. Their web site even states E Load in the specs.

Solitude Specifications

Don Z.

[Tin_Pusher]

It doesn't amount to a whole lot, but the axle rating does not include the weight of the wheels & tires (unsprung weight), at least acording to my Dexter stuff. So that's a couple hundred(?) lb to the good.

[JIMNLIN]

LT235/85-16 E at 3042 lbs per tire.

LT235/85-16 G at 3750 lbs per tire times 4 = 15000 lbs

[fj12ryder]

The axles on my Fuzion are 7,000 lb. rated axles from Dexter. They were de-rated to 6800 lbs. so Keystone could use E-rated ST tires at 3,450 each. I checked with Dexter so I would know the actual rating of my axles. The placard on my toyhauler says the axles are rated to 6,800 lbs. just so, IMO, they can use the junk E-rated ST tires.

[Me_Again]

Sounds like Sailun, Goodyear, Geostar or some other LRG tire.

But from their web site! Tires 16" / 8 lug / E rated and Axles 2 x 7000 lb., which would have to be a ST rated to 3500 or more, like some of the ST tires available rated to 3520 or more.

Something does not add up. Lets send in FE to smoke it out!

Chris

[fj12ryder]

With 20% of 16,000 lbs. (3,200 lbs) on the pin, that leaves 12,800 lbs. on the tires. The numbers work, but just barely. Not good enough for me.

[larry_barnhart]

Carriage was installing E tires on their latest trailers so I think he might be correct.
chevman