Tire Load Cpacity?

Dumb question maybe.

If the tire capacity rating for a tire is 1,000 lbs, does this mean that the total vehicle weight should not exceed the total capacity of the 4 tires.

1,000 x 4tires = 4,000 capacity so the vehicle should not exceed 4,000 lbs.

I see a lot of large cars with small tires especially on modern lowriders and I always wondered about this.

 

you absolutly undertand

 

There is a safety factor built in, but in practice, the maximum load should not exceed the tire rating.

 

Not a dumb question! And you've got it for the most part, but it does get a little more complicated.

You're assuming an equal weight on all of the wheels. Most cars do not have a 50/50 front/rear weight balance, so there's more weight on the front wheels than on the rear.

So, let's go back to your 1,000 lb rated tires and a 60/40 weight distribution (this is pretty nose heavy, just an example). Now if your front wheels are at 1,000 lbs each that makes 2,000 lbs 60% of your maximum weight. 2000=.6max, so max= 3,333 lbs.

Any more than that, with the horrible weight bias of 60/40, and your front wheels will be overloaded. This means the rears are only loaded at 666 lbs , but you can't load them more unless you change the weight bias of the car, or overload the fronts.

Just something to think about, if you have 1,000 lb max load tires you won't be able to get away with a 4,000 lb car unless your tuna boat has a perfect front/rear weight bias.

 

The maximum rated load is at the maximum rated pressure. Normally, tires are not expected to be run at max load/press on a continuing basis. Although one could argue that's what they're rated at, so why not. Simply wouldn't be prudent, in my opinion.

Tires on my heavy vehicle have pressure charts, showing what the pressure should be at various loadings, up to the max load, and also, if they are being run in single or dual mount. Running pressure at max psi without max load makes the tire "harder" and less able to withstand impact loads (potholes, curbs, etc.) . People get away with all sorts of abuse and misuse of products, tires are just one more item in that common circumstance.

Ray

 

how many sub 1000 lb cars do you know of?

 

I think the 1000# was per wheel/tire...........not total weight of the vehicle............the OP referred to 4000# car.

Ray

 

Sorry, I just re read the thread. My mistake

 

A lot of lowriders get cited for load rating on their tires. Remember the days when they would run 13" rims, 10' wide with VW tires. A good pothole and they would burst.