Are our tires safe?

[Archive]

Are out tires safe?

With all the news about bad tires causing accidents lately I've been curious about our owners manual recommendations about tire pressures. I have a 2000 2500 4WD QC with the Cummins Diesel. It came with Michelin LTX /AS LT265/75 R16 tires. When I read the sidewall of the tire is says inflate to 80 PSI. When I read my owners manual it states 45 PSI Front 40 PSI Rear (With Light Load) and 60 PSI Front 70 PSI Rear (With Full Load).

I know all the stuff in the news is with regard to Firestone tires from one particular plant. I also know from reading that in most all instances where these tires failed, the tire(s) in question were underinflated.

When I first picked up my truck from the dealer there tires were @72 PSI. At that pressure the truck wandered all over the road, when I reduced the pressure to what my owners manual states the wander disappeared.

Does anyone have an "in" at Michelin so we can get a strait nonbiased answer on this?

Thanks,

Kevin


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Kevin J. Donovan

 

[Archive]

Hi KJ,
The only way to know if you have the correct air pressure in your tires is to have your truck weighed. Get the individual axle weights. Then get a copy of the load/inflation tables for your make/model of tire and inflate to the correct pressure in the tables. You can get the load/inflation charts at a Michelin dealer or you may be able to find them on their web site. Or you can request them from Michelin.
I have the Michelin RV Tire Guide, it doesn't list the LT265/75R/16 tires probably to new.

For the LT245/75R/16 tires that's on my truck 45PSI will allow me to carry 4060 lbs. 40 PSI will allow 3730 lbs.

Tires will last longer and the truck will ride better if they are inflated to the load. And you don't have the worry of over heating the tires because of low air pressure.

The pressures you listed from the owners manual "sound about right", but it never hurts to check #ad
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[Archive]

I lost the tread on one of my original Goodyear tires while going 65 mph with a camper on board. The tires still had about 60% of their tread life left. It happened without much warning, a sudden vibration and a loud bang. It was inflated to 80 psi. The tread put a hole in the rear overhang of my camper and destroyed the right rear fender and box side. I was able to pull over and replace the tire with the spare and continue on. The tire never lost any air. Goodyear dealer said he never saw that happen before but body shop said that was second Dodge 4x4 with Goodyear tires he had seen with identical damage within a month. Goodyear replaced all four tires but I had to pay for pro-rated usage on the 3 good ones. This was in 1998.

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Ron

'96 Club Cab 2500 4x4, 4:10LS, Auto, BD Pressure Loc, Mystery Switch,TST 230/605, Cummins Chrome, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, All black. Tow 14k HitchHiker triple glide 5th Whl. Also use 9. 5' Lance. NRA Life Member.

 

[Archive]

The 80psi listed on the sidewall is the pressure you should run at max load (which should also be on the sidewall). When you are running below max load, you should use a fraction of the max pressure that is the same as the fraction of weight to max weight. i. e. if the tire is rated at 80 psi @4000# and you are running 2000# on that wheel, your pressure should be 40psi. This is not exact since you have a little added strength from sidewall stiffness, but this gets you pretty close.