1999 Montana Tire Pressure

[larrysbk]

I have the 1999 Extended Version. The maximum tire pressure imprinted on my Bridgestone tires is 44 PSI at 725Kg Max Load. The label on the door jamb states 35 PSI Cold. So, what should my tire pressure be?

[1999montana]

I run our Michelin MX-4's (now known as the 'Harmony' or 'Destiny', I think) on our EWB van at 35 lb. front and rear. It's a little firm, but the tires have lasted 115,000 kms and I expect to get 130,000+ before I replace them this fall.

If you try to run them at 44 lbs (cold) you will exceed the recommended inflation rate for the tire at highway speeds (due to heat build-up).

The result could be a ply separation, or worse if you do.

[dewaynep]

Actually, an underinflated tire will cause heat buildup, tread seperation, etc. The tire pressure stated on the door post is what you should fill your tires to. The maximum listed on the tire is just that, a maximum. The tire pressure on the door post takes into account the van's load capabilities and the tires contact patch. Think of it this way (oversimplified with generic numbers to make it easier): Your van weighs 4000 pounds (1000 pounds per tire, oversimplified-yes), at 35 psi your tire contact patch is about 28.5 square inches. Raise that tire pressure to 44psi and the contact patch is reduced to 22.7 square inches, almost 6 square inches less tire contacting the road. Well, you say, why wouldn't I then want to underflate my tires slightly so I can get more rubber on the road? That is when sidewall blowouts and tread separation happen from heat buildup. To make a long story even longer - just follow what is posted on the door...

[rkvons]

Yeah, and if you don't have an air compressor at home, you have to drive somewhere, over-inflate slightly, then park it at home and the next morning (when the tires are cold), release air until they are 35 psi.

[merc81]

Originally Posted by rkvons

Yeah, and if you don't have an air compressor at home, you have to drive somewhere, over-inflate slightly, then park it at home and the next morning (when the tires are cold), release air until they are 35 psi.

You go to walmart or Advance auto or the local dollar store and purchase a 12volt powered compressor and store it in your van.

[rockwood84]

go with 32 to 35 pounds