View Single Post
      09-09-2009, 07:27 AM   #31
kmac1980
Major
27

 
Drives: '11 535xi, (former '08 M3)
Join Date: Jan 2006
Location: toronto


Posts: 1,025
iTrader: (1)

great write up... im sure most consumers wouldnt have a clue..

Quote:
Originally Posted by M3V8Driver View Post
Here's a neat little tidbit I found while searching ont he referenced SAE tst:
Are Your Wheels Safe?
Have you ever wondered if the aftermarket wheels you are putting on your rod or family car are safe? When you and/or your family take off on a trip to the local store or across the country are you confident your wheels will not fail? Here are a few things you should know.

There are no government standards or regulations that require a wheel manufacturer or importer to meet in order to sell a wheel in the US. There are several marking and dimensional requirements that are required by the DOT (Dept. Of Transportation), but no performance or testing requirements.
The standards for performance and testing are voluntary on the part of the manufacturer or importer. There are several specifications that are considered recommended practice, available from such organizations as SAE (Society of Automotive Engineers), TUV (the German regulatory agency), ISO (International Standards Organization), and JWL (Japan Light Alloy Wheel Testing Council Rules). The SAE J2530 Aftermarket Wheel Performance Requirements and Test Procedures is a new standard developed for the aftermarket wheel industry to assure that the wheels produced for use on passenger cars and light trucks are safe and reliable.
The testing requirements of J2530 are composed of 3 performance tests.
The first is a Dynamic Cornering Fatigue Test. This is a test that simulates the forces of load put on a wheel when the vehicle is turning a corner or going around a curve.
The second is a Dynamic Radial Fatigue Test. This is a test that simulates the forces of load that the wheel experiences with a tire mounted and carrying the weight of the vehicle, passengers and or cargo.
The third is an Impact Test. This is a test designed to test the effect on the wheel in the event of an impact to the wheel such as hitting a pot hole or side impact into a curb.
The quantity of wheels required to complete the testing are as follows:
Cornering Fatigue = 2 up to 7
Radial Fatigue = 2 up to 7
Impact = 2
The Cornering and Radial test sample quantities are calculated based on number of cycles and test load settings. In other words, the fewer test samples the greater number of cycles and the higher the test load or the tougher the test. In addition to the above, the tests are based on per style by size. For example, sizes 17x8 and 18x9 of the same style require a minimum of 6 test samples per size. Makes one wonder how or even if some of these “One Off” wheels are tested.
Marking requirements:
The markings that are required by DOT are as follows;
Wheel Load – this is the maximum load that the wheel is designed to carry. The wheel load is determined by taking 50% of the heaviest axel rating of the vehicle (GAWR – gross axle weight rating). Example; if your heaviest axle weight rating is 3000 lbs then your wheel load requirement would be 1500 lbs.
Wheel size (example 15x8).
Wheel manufactures name, trademark or symbol.
Date of manufacture of the wheel, indicating month and year.
Manufacturers part number or code.
Country of manufacturer.
The symbol “DOT” constituting a certification by the manufacturer of the rim that the rim complies with all applicable vehicle safety standards.
Here is a simple way to determine what a safe wheel load rating should be for your vehicle.
The first thing to do is check to see if the vehicle has the original data plaque. Normally it can be found in the door jam or door on the driver’s side.
If that isn’t available then use the following rule of thumb;
Passenger cars (not including stretch limo’s) = 1400 lbs
Pick Up trucks – bolt patterns 5x4.50” & 5x4.75” = 1600 lbs
Pick Up trucks – bolt pattern 5x5.00” = 1900 lbs
Pick Up trucks – bolt patterns 5x5.50” & 6x5.50” = 2100 lbs
Pick Up trucks – 8 lugs = 3400 lbs
In summary, unless your rod is a Trailer Queen or you only drive it to local cruises (not exceeding 40 mph or so) a few times a year, you need to make sure your wheels are safe. There are a lot of folks out there selling, building, importing and modifying wheels that when they read the above, it will be the first time they’ve heard it.
You can find the above at: http://www.performanceplustire.com/tech.info/3