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-   -   Max load for tires (https://www.rx7club.com/1st-generation-specific-1979-1985-18/max-load-tires-439663/)

Mikeee 07-02-05 06:39 AM

Max load for tires
 
I dont understand how this works exactly. I read a few articles about tires and most my questions have been answered except 1.

Max load for tire, how is that rated? I mean if a car weighs 2000 lbs, and the tire is rated to hold a max load of 2000 LBS, does that mean that each tire will hold 500 LBS? (the average weight distributed over all 4) -- or does it mean that the 4 tires will hold upto 8000 lbs combined?

Sorry if its a dumb question, I just need to know because Im building a show car and its going to have a an extra 1500 lbs or so in it. Thanks.

Re-Speed.com 07-02-05 07:20 AM

If your car is 2000 pounds, each tire would have 500 pounds of load. This is assuming perfect weight distribution.

If your tire choice has a 2000 pound max load and 500 pounds is used by static weight, you are left with 1500 pounds per tire for extra weight.

-billy

Mikeee 07-02-05 07:28 AM


Originally Posted by bwaits
If your car is 2000 pounds, each tire would have 500 pounds of load. This is assuming perfect weight distribution.

If your tire choice has a 2000 pound max load and 500 pounds is used by static weight, you are left with 1500 pounds per tire for extra weight.

-billy

Ok. So Subtract car weight from total max load lbs of 4 tires, and Im left with the max extra weight allowed. (since you said per tire I assume this is correct)

Car=2000 lbs
Tire max=2000 lbs

2000 lbs x4=8000

8000-2000 (car) = 6000 lbs allowed extra? seems a but much

Re-Speed.com 07-02-05 12:56 PM

http://www.tirerack.com/tires/tirete...ey.jsp#maxload

Mikeee 07-02-05 01:02 PM

I've read that article since it was the first to come up in google, didnt help with my specific question, thanks tho. Can anyone verify the above math is correct?

trochoid 07-02-05 03:34 PM

Your math is correct. However keep in mind that it is maximun load, which includes dynamic loads, i.e. cornering, braking and acceleration forces. Those can add up quickly.

The tires may be rated, in your example, for 8000 total load, but you will be limited by the chassis and suspension long before the car itself weighs out at 4 tons.

Look on the drivers door pillar and you will find a load capacity for the car, it is not much in a 7. You will easily exceed the load capacity of the car, before you exceed the the tire capacity rating. The load rating of the car is not just limited by the suspension. It is also limited by the brake and drivetrain capacities.

Re-Speed.com 07-02-05 03:37 PM

Yes, your math is correct.

You should not MAX out the tire ratings though. There is weight transfer when the car is in a corner (roll) or accelerating or braking. The static numbers will be multiplied numerous times from weight transfer.

How much Boom-Boom you planning to install anyways?


-billy

Mikeee 07-02-05 07:02 PM


Originally Posted by bwaits
Yes, your math is correct.

You should not MAX out the tire ratings though. There is weight transfer when the car is in a corner (roll) or accelerating or braking. The static numbers will be multiplied numerous times from weight transfer.

How much Boom-Boom you planning to install anyways?


-billy

Well the whole things is fiberglass and bondo, lots of it, from the dash to the back, I dont have a decent scale, but equipment itself is over 1000 lbs. And I assume the rest will be around 1500 lbs. Im going to do the suspension work but I dont want to be popping stems every time I roll it off a trailer to a show.

trochoid 07-02-05 07:11 PM


Originally Posted by Mikeee
Well the whole things is fiberglass and bondo, lots of it, from the dash to the back, I dont have a decent scale, but equipment itself is over 1000 lbs. And I assume the rest will be around 1500 lbs. Im going to do the suspension work but I dont want to be popping stems every time I roll it off a trailer to a show.

You might want to concider stiffening the chassis first. Maybe seam weld it and add a cage. You don't want it to be a lowrider, just between the wheels. You could probably intergrate the cage in the design. If you are going for sounds drags or whatever, I highly recommend the seam welding.


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