How do you decide on tire pressure?

[opus]

Do you go by the GVWR plate on the bus, by the pressure on the side wall or do you weight front and back and go by the chart of your tire manufacturer?

[wildbob24]

Weigh the bus and use the manufacturer's chart

Bob

[dtcerrato]

Ditto

[TomC]

My bus weighs 10,500lb front, 20,500lb rear (2 axles). Tires-Michelin XZE 11R-24.5 H rated (16 ply). By Michelin's tire inflation table, 80psi front is 10,620lb, 85psi rear is 21,040lbs. I run 90psi all around for a bit of margin. My tires say maximum inflation of 130psi. If you run that, your bus will ride like a fork lift and your tire foot print will be reduced-meaning less contact with the pavement and less traction. Good Luck, TomC

[opus]

My bus weighs 10,500lb front, 20,500lb rear (2 axles). Tires-Michelin XZE 11R-24.5 H rated (16 ply). By Michelin's tire inflation table, 80psi front is 10,620lb, 85psi rear is 21,040lbs. I run 90psi all around for a bit of margin. My tires say maximum inflation of 130psi. If you run that, your bus will ride like a fork lift and your tire foot print will be reduced-meaning less contact with the pavement and less traction. Good Luck, TomC

Mine is 9000# front, 16,000# rear.  Cooper RM254 16 ply and they say its about 75.  Figured I'd go 85psi.  Make sense?

[PP]

For simplicity's sake, I have been running 100 PSI all around, but I think I can lower the rears to 90 and still be above the tire mfg's recommended based on weight.
HTH

[luvrbus]

The bus OEM plate recommendations are for the highest axle weight and all types of road and driving conditions there is nothing wrong with it.I shy away from adjusting tire pressure just for the ride keep your 100 psi   

[dtcerrato]

I don't "cushion" the weight capacity as much as stated here. I run pretty close to what the tire mfger states on the particular tire's load charts, maybe a couple psi higher for good measure. As Tom stated, the foot print matters too! The difference from running 100+ psi and mfger stated pressure is phenomenal. Fork lift vs total comfort, safety, & driveability...

[luvrbus]

Foot prints don't change on a radial tire with air pressure,if it does the Michelin engineers are way off 

[Tony LEE]

Foot prints don't change on a radial tire with air pressure,if it does the Michelin engineers are way off  

How do you explain lowering tyre pressure when driving in sand.

The transverse measurement of the footprint doesn't change much with pressure because the tread width doesn't change and any bagging takes place higher up the sidewall but the longitudinal footprint changes a lot  and that is easily shown by parking on smooth concrete and sliding bits of paper in from all four directions until they touch the rubber and measuring the gaps between the paper.


BTW reason tyre fitters will tell you 100psi all round is that is all they can remember without needing it written down

[luvrbus]

Michelin, Bridgestone,Toyo and Goodyear engineers have all told me because I asked the foot print will not change from min to max air pressure on a radial truck tire that's all I know,the tread design since the 90's prevent it 

[PP]

We drop pressure on our off road vehicles all the time when in the dunes. The width doesn't change on the tire foot print, but the amount of tread front to rear (longitudinal) does which has a huge effect on ground pressure, preventing the vehicle from sinking into the soft sand as easily.
HTH

[eagle19952]

We drop pressure on our off road vehicles all the time when in the dunes. The width doesn't change on the tire foot print, but the amount of tread front to rear (longitudinal) does which has a huge effect on ground pressure, preventing the vehicle from sinking into the soft sand as easily.
HTH

but that isn't really how bus OTR tires are designed...you are comparing bananas to peach baskets....totally different species 

[RJ]

I use the tire manufacturer's chart for the size and load range for my tires, which, in my case, works out to only 75 psi front and rear. 

Too soft for my taste and pucker factor, so I added 10 psi all around and now run 85 psi.

Gives the MCI MC-5C a really nice ride for its 25,500 lbs, and the Tire Tracker pressure monitoring system makes it easy to keep an eye on them.

FWIW & HTH. . .

[PP]

but that isn't really how bus OTR tires are designed...you are comparing bananas to peach baskets....totally different species 

They're both round and if you flatten the bottom down, you change the amount of surface area in contact with the ground. I would never do this with the tires on my bus. They're way too expensive to be mucking around with. But then, I'm not familiar with peach baskets. Is there a reason you can't put bananas in a peach basket?