Ford Racing alloy wheel testing standards...

[HoustonMustang]

Ford Racing alloy wheel standards...

Interesting reading...copied from their website...very impressive!

http://www.fordracingparts.com/


FRPP uses the Society of Automotive Engineers (SAE) and American Society for Testing and Materials (ASTM) Standars: SAE J175 and J328 for impact and fatigue testing and ASTM B368 for chrom testing. These standards define a series of tests that ensure the safety and finish of a wheel.


THESE TESTS ARE THE MINIMUM STANDARD USED TO DEFINE THE ENDURANCE OF FRPP WHEELS.


Impact Testing
This test simulates a curb impact on the side of a tire/wheel assembly. During testing, a tire/wheel assembly is mounted at a 13-degree angle to a test fixture by the hub. A weight is dropped from 9 inches onto the assembly at the tire/wheel intersection. The mass of the weight is determined by a formula, using the vehicle weight.

Dynamic Cornering Fatigue TestingThis test simulates lateral loads applied to a wheel by the vehicle. During testing, a wheel is clamped to a fixture by the front face and a constant bending moment is applied through the hub. A wheel of new design will run a minimum of 1,000,000 cycles before approved. The load applied is determined by a formula, using the vehicle weight.

Dynamic Radial Fatigue Testing
This test simulates axial loads applied to a wheel by the vehicle. During testing, a tire/wheel assembly is mounted to an axle by the hub. A large drum drives the assembly while a load is applied perpendicular to the tire patch. A wheel of new design will run a minimum of 5,000,000 cycles. The load applied is determined by a formula, using the vehicle weight.

Chrome Quality Testing
Copper-accelerated acetic acid-salt spray, commonly known as CASS testing, is the standard method used to test the corrosive performance of copper/nickel/chromium-plated wheels. The test is performed in a sealed chamber with a highly acetic spray directed onto the wheel for a predetermined amount of time, usually 66 hours.








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[JimmyTwoTimes]

Dynamic Radial Fatigue Testing
This test simulates axial loads applied to a wheel by the vehicle. During testing, a tire/wheel assembly is mounted to an axle by the hub. A large drum drives the assembly while a load is applied perpendicular to the tire patch. A wheel of new design will run a minimum of 5,000,000 cycles. The load applied is determined by a formula, using the vehicle weight.

5,000,000 cycles of a 27" diameter wheel/tire = ((3.14159*27)*5,000,000)/63360 = 6693.7 miles. So they're testing a wheel hub's axial life based on less than 7,000 miles of lifetime wear.

That seems... ludicrously insufficient.

 

[HoustonMustang]

5,000,000 cycles of a 27" diameter wheel/tire = ((3.14159*27)*5,000,000)/63360 = 6693.7 miles. So they're testing a wheel hub's axial life based on less than 7,000 miles of lifetime wear.

That seems... ludicrously insufficient.

Sorry JTT...your equation values are incorrect...

;)

 

[Herr_Poopschitz]

5,000,000 cycles of a 27" diameter wheel/tire = ((3.14159*27)*5,000,000)/63360 = 6693.7 miles. So they're testing a wheel hub's axial life based on less than 7,000 miles of lifetime wear.

That seems... ludicrously insufficient.

5 million cycles is a lot. If the material does not fail by then, it probably won't. The stresses applied are probably lower than where the SN curve goes horizontal, the testing is just validation of what the calculations show. Also note that we don't know the loads applied...only that they are calculated using the vehicle weight. I would imagine a fairly high margin of safety is used for factory type wheels...

Click on the 'high cycle fatigue' tab for more...
http://en.m.wikipedia.org/wiki/Fatigue_(material)

 

[BmacIL]

5,000,000 cycles of a 27" diameter wheel/tire = ((3.14159*27)*5,000,000)/63360 = 6693.7 miles. So they're testing a wheel hub's axial life based on less than 7,000 miles of lifetime wear.

That seems... ludicrously insufficient.

You drive around at over max GVWR for 6600 miles?

Also Herr_Poopschitz comments are right on. Aluminum fatigues different than steel, and never gets that nice infinite asymptote on the S-N curve. Just because they only test it to 5,000,000 cycles doesn't mean that they consider 5,000,000 cycles "good". There is safety factor built into it based on the result from that quantity of cycles (and also a lot of prior knowledge).

 

[RubyRed15]

It says "5,000,000 cycles"...not revolutions. I'd interpret that to mean the axial load is applied 5M times.

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