First time at truck scales - understanding tire load tables ...

Eric B

Active member
Hi all

With most items I plan to do now completed on my light build I filled up the diesel tank and took the van down to my local truck scales.

With the only person on site safely behind his plexi screened office and no one by the scale itself, I figured I would position the van as pictured below.

I eyeballed middle of the wheelbase - not middle of the OAL of the van. Correct?

I was surprised the van got nearly 50/50 weight distribution without me in it - 3580 F and 3560 R


Are tire load tables specific to a given tire make & model ?
Or will any LT tire/Load E table do?

On the tire table below, the weight listed is PER TIRE, right? not per axle ?
So at just under 1800lbs per tire, I could be running 35psi all the way around ?
Am I reading the chart correctly ?


I've been running 45psi F and 60psi R to date but guess I can drop the rears down a bit now, right?

please advise...
 

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sailquik

Well-known member
There may be tire specific load and inflation tables.
What tires do you have?
What size, what model, what manufacturer?
Why are you not running the inflation pressures that are listed on
your "B" pillar and the capacity plate on the side of your driver's
seat box?
I've got well over 1/2 million miles in Sprinters, and have always run
the exact pressures listed on the capacity plate.
I drive 5 16/519/ 3500's for the aded towing capacity but my 7 tires have
always lasted > 100k miles (Michelin LTS M/S/ Defender LTX M/S).
Roger
 
I use the Michelin tire guide. The standard on my 3500 is 61. Too high. My rear is 7220 I run 57 but the guide is 55 at 7440, the front I run at 52 at 3780 the guide would be 50 at 3880. I am running Michelin Agillis 215 85 R 16 E

I have Continental Cross Climate before, use the guide, Continental did not provide one. Goodyear had the same PSI in their guide.
Weigh it, get it aligned and use the correct PSI. You will love the ride.
 

autostaretx

Erratic Member
A thing to remember is that, during emergency stops (when you'd like your tires to not blow), a heck of a lot of the rear wheel weight gets transferred to the front wheels as you "jack it up" by standing on the brake pedal.
((yes, less than used to happen before anti-lock braking systems, but there's still a transfer))
Hence a bit of "extra capacity" doesn't hurt.

--dick
 

TrackSprinter

2016 Low Roof 144 2500
good for me to learn new stuff every day.

i was purposely running lower pressures however, it was a little off the last time because i did not recheck the pressure when i returned to sea level from the mountains. its weird because i cannot get the TPMS to properly recalibrate (after off-road air down) unless I go way back up/over to "spec" air pressure, and then the stupid dash warning will disappear. don't remember now but i think i was at 47F/57R. i had them reset with the tool but the error remained, it was probably the rear pressure preventing the ECU from liking the reading.
 

Cheyenne

UK 2004 T1N 313CDi

Roamers

2020 4X4 170 Crew
Although things change, in the past, manufacturers used the TRA (Tire and Rim Association) load tables. I assume they still do. Why develop your own when there is a proven industry standard. If you look at the vehicle label, the pressures typically align with fully loaded axles.

Although my knowledge and experience with tires was developed with construction and agricultural equipment, I apply it to my motor vehicles also. Tire pressure that aligns with your use case gives a more comfortable ride and better performance.
 

Eric B

Active member
I have the same BFG A/Ts that every one else has in the typical size of 265/75R16 on the stock steelies.


@sailquik

MFG tire pressure values on the B pillar sticker are for a FULLY LADEN to GVWR, are they not?
The GVWR on a 170 High Roof Diesel 4x4 is 9050lbs

I'm at just over 7000lbs and have no intention of getting close to GVWR

Doesn't that therefore mean that I don't need to run full listed pressures?

If I use the 45/65 that is recommended on the B pillar sticker, and I am nowhere near the max GVWR, then aren't my tires overinflated, and I am not putting down the full contact patch I should be putting down ?? ....

If I'm wrong, I'm all ears...


@Cheyenne

If my front axle weight is 3580lbs, then each tire is responsible for 1790lbs, which is 812kg, which in turn equates to next highest Load Index of 101 on page8 of your Continental PDF, right?

Page 22 on the Michelin PDF, shows that a pair of 265/75R16 LTX on a single axle, inflated to 35psi can carry a load of 3820lbs.
Am I reading this right ?


As @Roamers is saying, I also thought recommended tire pressure was with the MFG assuming you will be using your cargo van as intended - ie to haul cargo - and up to 3395lbs of it ... which I'm not ...
 

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Cheyenne

UK 2004 T1N 313CDi
If my front axle weight is 3580lbs, then each tire is responsible for 1790lbs, which is 812kg, which in turn equates to next highest Load Index of 101 on page8 of your Continental PDF, right?
No.

The tyres MUST be rated for the maximum permitted axle weight, be it front or rear. Take the higher of the axle weights from the VIN plate and divide by 2 (You do not divide the GVWR by 4 as this may give a tyre load index that is too low for one axle).

Page 22 on the Michelin PDF, shows that a pair of 265/75R16 LTX on a single axle, inflated to 35psi can carry a load of 3820lbs.
Am I reading this right ?
Yes, I agree with that figure.

The same tyre size in the Conti book (albeit under the 4x4 section on page 64 rather than van tyres from page 80) gives an axle weight of 1,780 kg at 2.5 bar which equates to 3,920 lb at 36 psi so very similar figures to Michelin.

Keith.
 

kcshoots

VanTripping.com
Yeah, having weighed my fully completed build many times, and at each corner (one wheel on scale at a time), I see that front axle receives about 45% of my van's total weight, which shows that a lot more weight can and should be placed to the rear than it seems most people think. Here is a tire size pressure calculator for determining weight carrying capacity by tire size and pressure, as well as ability to compare sizes and pressures to carry the same weight. https://tiresize.com/pressure-calculator/
 

Eric B

Active member
@Cheyenne

Just to be clear, I wasn't suggesting I'd be running a lesser tire that can't handle weight. My BFG A/Ts are Load E so I'm good there.
I think I was getting confused on the different charts in the PDF... Thank you for explaining correct way to proceed.

@kcshoots thanks for the link, I'll check it out
 

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