Tire Loading and PSI

[Mr Wonderful]

Were completing our Freshman season. Have so much to LEARN. Great forum.

I'm investigating weights, tire loading and pressures.

For some background..

I have a 1Ton GMC 2019, and was just interested in her weight unhitched. I brought it to the Cat Scale with the following results

Steer Axle 4900
Drive Axle 3860
Gross Wght. 8760

Truck
GVWR sticker is 11500
Payload sticker is 3475

I have a loading chart from my tire mfg that recommends varying tire pressures depending on the load on the tire.

I don't see from the Cat Scale report a weight for each tire? Or do you just divide the axle weight by two and use that as a close approximate?

Although this is a truck question for overall reference we are in a 21' GB 27FB.

Sorry if I sound like a dunce, just wanted to see what others are doing?

[ITSNO60]

Standard recommendation is to add 10% to allow for uneven side to side loading. That said, when my F350 is unladen even adding 10% puts my rears between 35 and 40. I don't run them that low, instead I keep all four around 60 when unladen, I need the 60 in front due to diesel engine weight.

[Mr Wonderful]

Originally Posted by ITSNO60

Standard recommendation is to add 10% to allow for uneven side to side loading. That said, when my F350 is unladen even adding 10% puts my rears between 35 and 40. I don't run them that low, instead I keep all four around 60 when unladen, I need the 60 in front due to diesel engine weight.

Thanks ITSN. So I understand your taking the axle weight / 2 and adding 10%?

Are you aware of any commercial scales that measure loads per tire?

[richard5933]

Originally Posted by Mr Wonderful

Thanks ITSN. So I understand your taking the axle weight / 2 and adding 10%?

Are you aware of any commercial scales that measure loads per tire?

Check the Google Satellite view for the CAT scales near you. Some are configured with the scale plates even with the surrounding asphalt and in such a way that lets you drive onto the plates with only one side of your truck on the scale. This gives you the weight on one side. Go around, do a re-weigh with the other two on the scale.

You might not be able to do this with the steer axle on the front scale plate where it normally would be, but you can usually get the axles each on one of the plates further back.

Some are built with the scale raised up above the surrounding parking area, so obviously this method won't work.

If the CAT scales near you can't do this, start searching for other scales in the area. I've seen some independent truck stops and fuel stations which have scales open to the public, and many of these are built without anything blocking you from straddling the scale plates to get one side measured at a time.

[ITSNO60]

Originally Posted by richard5933

Check the Google Satellite view for the CAT scales near you. Some are configured with the scale plates even with the surrounding asphalt and in such a way that lets you drive onto the plates with only one side of your truck on the scale. This gives you the weight on one side. Go around, do a re-weigh with the other two on the scale.

You might not be able to do this with the steer axle on the front scale plate where it normally would be, but you can usually get the axles each on one of the plates further back.

Some are built with the scale raised up above the surrounding parking area, so obviously this method won't work.

If the CAT scales near you can't do this, start searching for other scales in the area. I've seen some independent truck stops and fuel stations which have scales open to the public, and many of these are built without anything blocking you from straddling the scale plates to get one side measured at a time.

I tried that at one of our CAT scales and not only did it not work but the attendant came running out yelling at me "You can't do that on our scales!"

The only way I know of to get corner weights is to buy a portable scale or join Escapees Club and wait for a weighing event in your area.

[ITSNO60]

Originally Posted by Mr Wonderful

Thanks ITSN. So I understand your taking the axle weight / 2 and adding 10%?

Yes, adding a minimum of 10%. Like I said on my rears it is more than 10% when unladen.

[Tschupp]

Escapees “boot camp” in Congress AZ and had individual tire scales.

[cazual6]

Just as a side note. For my AS, I run at 65psi or even 60psi, anything higher will give your AS a rougher ride and pop rivets (from experience).

[Wazbro]

Originally Posted by richard5933

Check the Google Satellite view for the CAT scales near you. Some are configured with the scale plates even with the surrounding asphalt and in such a way that lets you drive onto the plates with only one side of your truck on the scale. This gives you the weight on one side. Go around, do a re-weigh with the other two on the scale.

You might not be able to do this with the steer axle on the front scale plate where it normally would be, but you can usually get the axles each on one of the plates further back.

Some are built with the scale raised up above the surrounding parking area, so obviously this method won't work.

If the CAT scales near you can't do this, start searching for other scales in the area. I've seen some independent truck stops and fuel stations which have scales open to the public, and many of these are built without anything blocking you from straddling the scale plates to get one side measured at a time.

You can also check places that sell stone by weight. Some will work with you to get weights if they aren't busy at the time. Though some are not setup so you can just weigh one side.

[Mr Wonderful]

Thanks all.

[jadatis]

If you give me the tirespecifications, I will make an extra safe pressure/axleload list for you.
For that I made a spreadsheet in wich I use a better calculation then those of the lists, and go from 90% used from the loadcapacity for the pressure.
This gives max reserve with still acceptable comfort and grip, for an LT tire.

Need
1. Maxload or loadindex
2. Loadrange to determine reference pressure, but better if given on sidewall, pressure behind AT given
3 speedcode would be nice.
And if you want other reserves, write it.
Also give dual maxload.