Tire and Axle Numbers don't add up - Do Yours

[One_Mad_Marine]

I have a 2014 Forrest River\Prime Time\Spartan 1032. This is a a toy hauler. The UVW is 12,500 lbs. You can add up to 4000 lbs. in gear, water and toys. This brings the weight up to16,500 lbs. +/-.

Here is the bull - the axles are rated at 7,000 and the four tires together are at just over 12,000.

I have had 2 blow outs in the last 4 months when I was at 15,500 lbs. Both over the axle and tire rating. The tire rating actually goes DOWN for double axle trailers! I have talked directly with axcle manufacture and they said that this configuration is in voliation of their recommendations -

So here is my question -

Do anyone else have these types of numbers where the total vehical weight far exceeds the axle and tire recommedations -?

and two - if you do - are you willing to help with a class actions lawsuit? I am at about 9,000 dollars in damages from these 2 blow outs!

No comments on China Bombs - Here is the link to the Towmax website - look at the 235/80 R16

Towmax STR II Tires | Own The Road

[emm-dee]

IIRC, the tire max weight limit does not reduce with dual axles (tandem) but do reduce for dual wheel installation.

4,000 pounds sounds like a very generous weight for payload. Have you taken your rig to a Cat scale, or similar, to get actual weights? Remember that if your total trailer weight is 15,500 then there's probably about 2500 pounds on the hitch...meaning there's 13,000 pounds on the tires.

[Toddupton]

It's all about the math, the correct math. You have to calculate hitch weight into it also. I bet your rig is not ever the max axle weights or tires weights. You are most likely right at the max but not over.

[lbrjet]

Your axles are 14K and your tires are 14K. The dual rating is for four tires on one axle, you are misinterpreting the meaning. The unit has a dry 2500 lb pin weight adding up to 16.5K. Get some 'G' rated ties with a higher load capability to give you some margin when fully loaded. A lawsuit is not in the cards.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[JohnE]

Your hitch weight can be as much as 20% of your total vehicle weight, so if you vehicle's loaded weight is 16000 lbs then your hitch weight could possibility be 3200 lbs. This will result in your axle and tire weight being 12800 lbs. I am assuming that you have E rated tires on your RV which have a maximum speed rating of 65 mph. If you operate them at 65 mph or higher you are heating them up and will increase your change of tire failure. I would highly recommend you get G rated tires which will give you a maximum speed rating of 75 mph. Also the G rated tires will allow you to carry a load without being on the high side of their maximum loading carry capacity. A really good G rated tire is the Goodyear G614, which are also made in the USA. I have them on my 16500 lbs 5th wheel and have not had any more tire blowouts.

[DickiedooFlagman]

Originally Posted by emm-dee

IIRC, the tire max weight limit does not reduce with dual axles (tandem) but do reduce for dual wheel installation.

4,000 pounds sounds like a very generous weight for payload. Have you taken your rig to a Cat scale, or similar, to get actual weights? Remember that if your total trailer weight is 15,500 then there's probably about 2500 pounds on the hitch...meaning there's 13,000 pounds on the tires.

x2

[BusyRetirees]

My fiver came with 6 ply C rated tires with a load of 2025 lbs per tire. With 4 tires that is 8100 lbs. Fiver, fully loaded is 9200 lbs. Pin weight is 1190 lbs. Tire were 11 months old and developed cracks in tow of them and stretch marks on the other two. FR stated that he tires were "adequate" for my rig. I upgraded to 10 ply E rated tires with a load capacity of 2825 per tire. I have had no problems since. FYI FR did reimburse me $75 per tire.

[One_Mad_Marine]

I did not subtract the Hitch Weight - which is 2,700 Lbs. So if I subtract that from the 15,500 I am at 12,800. Which would put it under the 14k Axle limit nut still over the tire rating of what was on there.

Thanks for helping to find the error in my math

[Brother Les]

Tires can and will go down for any of a number of reasons. A very very small leak may happen or the tires may be low to begin with and looking directly at them a low tire may not be apparent. The first we may know of a tire issue is when we look in the rear view mirror and see tread and tire sidewalls flying all over the place and a slight swerve from the towed unit. "WE" will now call this a 'Blow out' and blame the tire......

Get one of these and monitor your tires and worry less about 'the weight'... the 'tires' and more about driving and what is in front of you.

507 Starter System Kit - Tire Pressure Monitoring Systems, Starter Systems - Truck System Technologies
phone # 770-889-9102

[DickiedooFlagman]

I had 3 tire issues in the first 5,000 miles. 1. The spare flat on delivery. Dealer checked all tires on receipt from factory in October; the spare had zero pressure on delivery to me in late April. Turned out to be sidewall pinhole leaks only found by submerging in a swimming pool. FR replaced. 2. Large sidewall bulge. FR replaced with a Load Range D in place of the OE LRC. 3. Another tire losing pressure while other 3 were not losing pressure. FR replaced with a LRC.

I was not happy with quality of OE tires and having them run so close to maximum design. At 5,000 miles I replaced 4 OE tires with Goodyear Marathons and increased Load Range from C to D. And retained the one replaced tire, Load Range D, for the spare. No more tire problems in next 10,000 miles, and counting.

[RadRik]

Originally Posted by Brother Les

Get one of these and monitor your tires and worry less about 'the weight'... the 'tires' and more about driving and what is in front of you.

507 Starter System Kit - Tire Pressure Monitoring Systems, Starter Systems - Truck System Technologies
phone # 770-889-9102

Brother Les, do these need to be taken off to add air?
Won't they change the wheel balance or is that very minimal due to being light weight?

[Airdale]

Originally Posted by One_Mad_Marine

I have a 2014 Forrest River\Prime Time\Spartan 1032. This is a a toy hauler. The UVW is 12,500 lbs. You can add up to 4000 lbs. in gear, water and toys. This brings the weight up to16,500 lbs. +/-.

Here is the bull - the axles are rated at 7,000 and the four tires together are at just over 12,000.

I have had 2 blow outs in the last 4 months when I was at 15,500 lbs. Both over the axle and tire rating. The tire rating actually goes DOWN for double axle trailers! I have talked directly with axcle manufacture and they said that this configuration is in voliation of their recommendations -

So here is my question -

Do anyone else have these types of numbers where the total vehical weight far exceeds the axle and tire recommedations -?

and two - if you do - are you willing to help with a class actions lawsuit? I am at about 9,000 dollars in damages from these 2 blow outs!

No comments on China Bombs - Here is the link to the Towmax website - look at the 235/80 R16

Towmax STR II Tires | Own The Road

The trailer manufacturer selects the Original Equipment (OE) tires based on the GAWR figures for each axel.

It is a common practice for trailer manufacturers to pick and set GAWR values that are less then the axle manufacturer's weight values for them.

Sometimes when using any of the ST235/80R16E tires on 7000# axles the trailer manufacturer must set the GAWR for those axles somewhere less then 6800# so the tires will be a legal (for them) fit. Without a notation on the certification label and in the owners manual some of the above tires will not qualify for service on GAWR 7000# axles. That's because there are three distinct maximum load capacities for the tires listed above. 3420#, 3500# and 3520#, all at 80 psi. The 3420# fitment would violate the trailer builders requirement for fitment on GAWR 7000# axles.

The math is simple for RV trailer tire fitments. Deduct the trailer manufacturer's published hitch weight from the certified GVWR. In your case divide by two. The result is the minimum weight requirement the trailer manufacturer must use for each GAWR. The tires then selected are - in the words of the regulation - appropriate for that fitment.

[lbrjet]

It's only appropriate if you feel that being at 100% of rating is OK. I don't care what the government or manufacturers say, I don't feel it is appropriate.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[Brother Les]

Originally Posted by RadRik

Brother Les, do these need to be taken off to add air?
Won't they change the wheel balance or is that very minimal due to being light weight?

I like this product because the owner (me) can change the batteries when they are low, instead of sending them back to the company for a new one.
I have 8 sensors, 4 for the camper and 4 for the truck. I lost tires on my truck alsom so this will help me keep an eye on all of them, constantly.

There are two 'styles' of the TST 507. One has the 'cap' and one is a 'flow throu'.

The cap style does need to be taken off, they come with a tool to install and take off in order to make them 'theft proof. It does not change the balance at all.

TST 507 Flow Thru - Tire Pressure Monitoring Systems - Truck System Technologies
507 Starter System Kit - Tire Pressure Monitoring Systems, Starter Systems - Truck System Technologies
(from web page)
How does your system work?
Each 510 wireless sensor weighs 23 grams, and each 507 sensor weighs 13 grams, both of which are negligible weights; each sensor screws onto the existing valve stem of each tire monitored while the receiver remains within your view in your vehicle. Each sensor has its own individual code that is easily entered into the monitor. This way, the monitor will only recognize and report data from your sensors and no other vehicle’s system. The monitor then highlights a tire and reports tire temperature and pressure. It will rotate around the electronic diagram on the screen and it will report temperature and pressure of each tire monitored approximately every two minutes. The system will immediately focus and report data and alarms will sound and icons will flash on the screen in the event of gradual tire deflation, rapid tire deflation, or elevated tire temperature.
The sensors transmit tire pressure and tire temperature to the monitor every two minutes unless a gradual tire deflation, rapid tire deflation, or elevated tire temperature event is encountered. In such a circumstance, the reporting is continuous until tire pressure or tire temperature returns to a normal range.
The system reports in PSI, KPa, Fahrenheit, or Celsius at the discretion of the system owner. The system is accurate to 0.73+/- PSI.
The sensor operating range of temperature is -40 through 257 degrees Fahrenheit or -40 through 125 degrees centigrade.
We can take the heat or the cold… Whatever Mother Nature dishes out, our system will handle!
Our sensors are operational in heavy rains, snow, high humidity, and wet or icy road conditions. Water in any form is no problem for our sensors.
The monitor can adhere to a dashboard AC vent using the bracket provided or you can adhere the monitor to your dash board using Velcro to hold it in place. Most users prefer to Velcro the monitor in place. Also, the 507 system includes a specially designed, windshield-mountable, suction-cup mounting bracket.

http://tsttruck.com/faq/

[emm-dee]

Originally Posted by Airdale

The trailer manufacturer selects the Original Equipment (OE) tires based on the GAWR figures for each axel.

It is a common practice for trailer manufacturers to pick and set GAWR values that are less then the axle manufacturer's weight values for them.

Sometimes when using any of the ST235/80R16E tires on 7000# axles the trailer manufacturer must set the GAWR for those axles somewhere less then 6800# so the tires will be a legal (for them) fit. Without a notation on the certification label and in the owners manual some of the above tires will not qualify for service on GAWR 7000# axles. That's because there are three distinct maximum load capacities for the tires listed above. 3420#, 3500# and 3520#, all at 80 psi. The 3420# fitment would violate the trailer builders requirement for fitment on GAWR 7000# axles.

The math is simple for RV trailer tire fitments. Deduct the trailer manufacturer's published hitch weight from the certified GVWR. In your case divide by two. The result is the minimum weight requirement the trailer manufacturer must use for each GAWR. The tires then selected are - in the words of the regulation - appropriate for that fitment.

Excellent explanation (and obviously written by an aircraft technician).

[SpringerPop]

I endorse Brother Les' advice to get a TPMS for your trailer. The -507 works wonders!

Knowing tire pressures has saved my bacon more than once, and it's money I get to spend on....

More bacon! Mmmmmmmm

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