Truck Weight and Tire Limit

[Jack90]

This has been on my mind for a while now, so I figured I would check in with you all and see which thinking is correct…

Weight Breakdown
Truck Weighs 7,500
Wet Truck Camper Weighs – 2,400
Total Weight – 9,900

Then very rough break down…
Front Weighs – 3750
Rear Weighs – 3750 + 2400 = 6150

Tires are a load E with a weight limit each of 3,195 pounds.


Question

Which is the right way to think about it?

A: You are good to go because 4 tires times 3,195 = 12,780, well within the limits and the weight is distributed across the four tires

B: No go because your rear weight is almost exceeding the rear tire weight limit – 2 times 3,195 = 6,390

 

[jadmt]

have you actually weighed your truck on a Cat scale? empty your truck is going to be heavier in front than in back by a fair amount if your truck weighs 7500 rear is probably closer to 3000lbs.

 

[mightymike]

I think you need to take your rig, fully loaded with water, fuel, gear, people, etc. to a commercial truck scale that can tell you how much weight is on each axle as well as giving you your total weight.

 

[Wilbah]

I agree with the comments above- only a scale will give you an accurate picture of the loads per axle. I saw a CAT scale receipt for a 2500 Duramax CCSB- total weight was 7,380# (w/driver & fuel), front was 4,260#, rear 3,120#. Your camper will obviously put more weight on the rear but also some on the front.

This wont be a perfect explanation but in essence the weight of the camper in front of the rear axle will be split somewhat between the front/rear axles while the weight of the camper after the rear axle will almost all be on the rear (depending on the rear overhang there could actually be some slight offsetting of front weight to the rear if the rear axle ends up acting a little as a lever but it would likely be minor). The bottom line is you need to fully load it for a trip and go to a scale to get an accurate weight per axle.

 

[nickw]

This has been on my mind for a while now, so I figured I would check in with you all and see which thinking is correct…

Weight Breakdown
Truck Weighs 7,500
Wet Truck Camper Weighs – 2,400
Total Weight – 9,900

Then very rough break down…
Front Weighs – 3750
Rear Weighs – 3750 + 2400 = 6150

Tires are a load E with a weight limit each of 3,195 pounds.


Question

Which is the right way to think about it?

A: You are good to go because 4 tires times 3,195 = 12,780, well within the limits and the weight is distributed across the four tires

B: No go because your rear weight is almost exceeding the rear tire weight limit – 2 times 3,195 = 6,390

Cat scales aside, using your math I think a pair of tires needs to be able to support actual weight placed on them....if it's below you are good to go, your option B. Obviously there is a massive factor of safety built into tires due to hitting debris on roads, rocks, curbs, etc. I would not exceed but I'd feel comfortable going up to.

 

[jbaucom]

Once you've loaded your rig and weighed it, and have your axle weights, the heaviest axle will determine the tire load index required to safely carry the load. If you stay within the MFG's GVWR and axle load ratings, then a tire that meets or exceeds the specs on the tire/load label inside the driver's door will be sufficient. If you're truly near the max load for your tires, then it may be time to find a tire with a higher carrying capacity for a bit of safety margin, depending on your use. On a maintained and properly inflated tire, it is designed to meet the specs (load at psi, speed rating) on the sidewall. If you do much interstate driving, consider the tire speed rating too.

 

[RoyJ]

What is the size of the tire?

All modern 17" tires are artificially limited to 3195 lbs. Some, like a 265/70r17E, truly were 3195 to begin with. Others, like a 37x13.5r17, E range @65psi, once had a 4,300 lbs rating.

If you happen to have the latter, or 35x12.5, you have plenty of real capacity remaining, as per laws of physics. As per DOT you're close, but it's Newton's law that causes a blowout, not DOT's...

 

[broncobowsher]

Your math is flawed. You assume that 100% of the camper weight is perfectly balanced over the rear axle.
What you need to know is where the CG of the camper is at and where it fits into the wheelbase of the truck. The further forward the CG is from the rear axle centerline the more weight is transfered to the front axle and less to the rear.

I will also guess that you are pulling published numbers and not what you are actually loading it to as well. Do you go out with no food, no cookware, nothing but water in the tank and the bottle of propane filled? Oh the stuff you put in the camper will also change your numbers. Most people highly underestimate the mass of the general stuff they put in there camper.

 

[Peter_n_Margaret]

In Oz, the tyre ratings must exceed the maximum axle ratings.
Might be OK today with something less, but tomorrow you may load the vehicle differently (but still legally).
Actual loadings are of no consequence to legal requirements.
Cheers,
Peter
OKA196 motorhome.

 

[billiebob]

This has been on my mind for a while now, so I figured I would check in with you all and see which thinking is correct…

Weight Breakdown
Truck Weighs 7,500
Wet Truck Camper Weighs – 2,400
Total Weight – 9,900

Then very rough break down…
Front Weighs – 3750
Rear Weighs – 3750 + 2400 = 6150

Tires are a load E with a weight limit each of 3,195 pounds.


Question

Which is the right way to think about it?

A: You are good to go because 4 tires times 3,195 = 12,780, well within the limits and the weight is distributed across the four tires

B: No go because your rear weight is almost exceeding the rear tire weight limit – 2 times 3,195 = 6,390

I doubt you have an issue but you need to scale each axle with the camper, full tanks, fully loaded including passengers and driver.
Without those numbers this is just a crap shoot.

But yes, the load rating is per tire, not an average of the vehicle over 4.

PS also compare the scaled weight with the sticker on the A Pillar. Regardless of the tires you cannot exceed the axle ratings on the A Pillar. Whichever is lower is your legal limit.

Truck empty will have more weight on the front axle than the rear axle. 7500/2 is not correct.

I swear some of these questions are just baiting us.

 

[ripperj]

You can divide the the total weight evenly by four and sleep well. It’s even better if you park next to another truck, then you divide by 8


Sent from my iPhone using Tapatalk Pro

 

[clydeps]

All modern 17" tires are artificially limited to 3195 lbs.

Better tell Gladiator Tires that - they specify a load rating of 4300lb for their 37X13.50R17LT. There are several other 17" tyres with published load ratings over 3195lb.

 

[FAW3]

Scale it. Try your local landfill scale. Pull on with front only, then both axles. Best loaded up as when travelin.