A quick question about tire load-bearing capacity.

stef · #1 09/10/10, 11:04 AM

If you plan on transporting a heavier than normal load in a standard sedan automobile, is it better to over-fill the tires with air, leave them normal, or a little under inflated?

Nothing illegal, immoral or fattening going on. Just need an answer about tire inflation.

thanks....

stef

DaleK · #2 09/10/10, 11:11 AM

Heavier than normal or heavier than your GVWR for the vehicle? If the vehicle's not OVERloaded , just make sure the tires are inflated to the proper pressure and you should be fine.

stef · #3 09/10/10, 11:13 AM

Quote:

Originally Posted by DaleK

Heavier than normal or heavier than your GVWR for the vehicle? If the vehicle's not OVERloaded , just make sure the tires are inflated to the proper pressure and you should be fine.

Heavier than normal and near the front end of the vehicle. Not sure about GVWR.

stef

Harry Chickpea · #4 09/10/10, 11:27 AM

If this is going to be a regular occurrence, replace the tires with light truck tires (LT designation). Be warned that the ride will be much harder and more noisy, and the tires are expensive and do not last as long. Did this with our van when I was using the cargo trailer a lot. I also added a tranny cooler.

I think in your case I would be concerned about the existing tie rod ends failing and such.

foxtrapper · #5 09/10/10, 11:36 AM

Increase the tire pressure.

Underinflated tires will run hotter and are far more prone to blowing out. They also wiggle side to side far more.

Low pressure for low load, high pressure for high load.

OJ Rallye · #6 09/10/10, 12:34 PM

Quote:

Originally Posted by Stef

If you plan on transporting a heavier than normal load in a standard sedan automobile, is it better to over-fill the tires with air, leave them normal, or a little under inflated? thanks....

stef

Tires used to have the maximum weight capacity @ maximum inflation on the sidewall. These days I think some only have the load rating in a 2 or 3 digit number that you have to look in the chart to see what the weight capacity is.

Bearfootfarm · #7 09/10/10, 12:45 PM

Quote:

Not sure about GVWR

.

The GVWR is probably on a plate or sticker on the inside frame of the drivers door.

The max weight rating and pressures are in small print on the tires

texican · #8 09/10/10, 12:51 PM

Remember... if you have a flat or blowout, with an extra heavy load... your vehicle is going to react a lot differently. Also, your jack might be underpowered if you have an extra heavy load. I have to carry 2 Tractor Jacks (Hi-Lift) at all times... a regular jack won't get my usually overloaded truck off the ground.

PhilJohnson · #9 09/10/10, 01:09 PM

Quote:

Originally Posted by Harry Chickpea

If this is going to be a regular occurrence, replace the tires with light truck tires (LT designation). Be warned that the ride will be much harder and more noisy, and the tires are expensive and do not last as long. Did this with our van when I was using the cargo trailer a lot. I also added a tranny cooler.

I think in your case I would be concerned about the existing tie rod ends failing and such.

Some truck tires will way outlast a car tire. It boils down to how soft the tread compound is. A soft snow tire will wear out way before a 8 ply highway tire will. General rule of thumb I use is the more aggressive the tread pattern is on a truck tire the less likely it is to last a long time. Truck tires with tread patterns meant more for street use will be as quiet as any passenger car tire.

I've overloaded a few vehicles, usually only for short distances. I always filled them up to the maximum PSI as listed on the sidewall. On a car tire that usually meant right around 35 psi. Some truck tires can go up to 80 psi or more. The weight rating will be on the sidewall of the tire in pounds. A severely overloaded vehicle will tend to wallow so care must be taken while turning corners.

I've never had a tire blow from overloading but then again I've always went slow, taken back roads, filled the tire up to the maximum PSI as listed on the sidewall of the tire, and made sure to slow down way ahead of time.

Danaus29 · #10 09/10/10, 01:50 PM

I would never exceed the max psi. Fill the tires up to the max but don't go over. Check your capacity weight on the sticker on the driver's door. As long as you don't go over that you shouldn't have any trouble. I would be more concerned about the possible damage to the car from being overloaded than the tires blowing out if you drive slower than normal, allow extra time for stopping, and take the curves easy.

The tires on our car call for 44 lbs max psi. We got heavy duty tires because we frequently haul a lot of extra weight in the car. When I drove full size station wagons I really loaded them down many times.

Bearfootfarm · #11 09/10/10, 01:54 PM

If the tires are cold when you check the pressure, you should put about 3# less than max

OJ Rallye · #12 09/10/10, 02:29 PM

Quote:

Originally Posted by Bearfootfarm

If the tires are cold when you check the pressure, you should put about 3# less than max

I've seen maximum cold inflation pressure and maximum pressure when mounting on tires but have never seen or heard of maximum hot inflation.

It's always been recommended to check tire pressure when they're cold.

dezingg · #13 09/10/10, 02:38 PM

I'd fill warm tires to the max rated pressure on the tire.

But you're not giving us much info. How much weight are you talking about? How much above the GVWR? How far a distance are you planning on driving? Most tires can handle being overloaded for short distances if you drive conservatively. But the heavier and further you are driving, the worse the risk is.

The best choice would probably be to have a friend with a good sized pickup haul it.

stef · #14 09/10/10, 02:43 PM

Thank you, everyone, for your input.
Sorry, can't give any more info than what I first posted.

You've all been helpful.

stef

GoldenCityMuse · #15 09/10/10, 09:12 PM

Cowards, all of ya'!

I've run 40psi in tires marked 35max psi for 10's of thousands of miles. And this in my MPV van loaded down moving. As another poster said, HEAT KILLS. So if you have to choose, go a little over.

Actually, some of my tires are rated 40psi, and I keep them at 48psi. Never had any problems. YMMV. And I am not ANY kind of tire expert. Take a calculated risk.

And BTW, you always fill a tire cold to at least the max pressure on the sidewall. They take into account the rise in pressure as it warms up.