wheel safety factor?

[Craig M]

Not sure if I should post this here or in the "trailer" section. Here goes. Anyone know of the approximate safety factors used in the design of steel and aluminum wheels for trucks. For example, a Alcoa 16" wheel may be listed as 3050# max allowable load. When that 16" tire and wheel combination hits a pothole at 65 mph the actual load that the wheel "gets" will be much heavier than the "rated" load. Dead load and impact load are applied to the wheel. I am familiar with safety factors of 2, 3 and 6 on other designed items, but have no personal experience on wheel design. Any one have any knowledge on wheel design?

[CleviteKid]

The rated loads for wheels are based on long-term fatique resistance, which does indeed impart a factor of safety of about 3 for incidental overloads. The fatique spectrum includes anticipated vertical load variations from rough roads, which can easily double the instantaneous load on the wheel.

Note that this is anticipated loads - the designer will refuse to anticipate that you are going to hit a pot-hole, 8 inches deep, with vertical sides, fully loaded, at 85 mph. You are outside the design envelope if you manage to do that.

[Robyn]

Another thing to think about.
If you are really worried about the safety issue go to a set of "Forged Wheels" and not cast aluminum.
All the big rig stuff is forged and will tollerate far more abuse than the standard passenger car/pickup look good wheels.

[CleviteKid]

If you are really worried about the safety issue go to a set of "Forged Wheels" and not cast aluminum.

Excellent advice. The Weld aluminum wheels on my truck are forged, not cast.

Dr. Lee

[DA BIG ONE]

Not sure if I should post this here or in the "trailer" section. Here goes. Anyone know of the approximate safety factors used in the design of steel and aluminum wheels for trucks. For example, a Alcoa 16" wheel may be listed as 3050# max allowable load. When that 16" tire and wheel combination hits a pothole at 65 mph the actual load that the wheel "gets" will be much heavier than the "rated" load. Dead load and impact load are applied to the wheel. I am familiar with safety factors of 2, 3 and 6 on other designed items, but have no personal experience on wheel design. Any one have any knowledge on wheel design?

Alcoa has a 3750 lb rated wheel one of the highest around for 2500/3500 series vehicles .

Steel GM wheels for 2500/3500 series should be the riveted type which have a letter code at the valve stem area, welded wheels are not up to the task. However, many aftermarket entities sell the wealer welded to replace riveted type.