The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Wheel industry test standards and certifications

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

We have learned from our many years running a race team that track wheels take more of a beating than street use will inflict. For a race team, wheels are considered a consumable, just like brakes, fuel and tires. For the weekend warrior or small team, the thought of disposable $400 wheels doesn't make sense though. This is why we stepped up from the 690-700kg JWL standard load rating. While everyone wants freakishly light wheels ( and wants them cheap), there is no magic that creates an affordable and truly robust wheel that is also the lightest on the market. You know the saying "Cheap, Light, Strong.. pick two".

www.949Racing.com

There are many engineering standards around the globe. Germany's TUV being the most stringent. JWL (Japan Light Alloy Wheel) standards being what most of the automotive aftermarket wheels sold in the US are engineered to. A company can claim to be "engineered to the standard" without ever actually being tested or certified. In Japan, an private company known as VIA provides unbiased, 3rd party certification. If a wheel has a VIA (Vehicle Inspection Association) stamp on it, a few examples of that exact variant have passed the rigorous testing protocol. This matters. Promising you did your homework is not the same as turning in that homework.

The three main JWL tests are thus

Radial fatigue
Wheel is loaded with rated weight, 770kg in the case of an 18" or 19" 6UL, tire mounted and inflated.
Drum rotates the tire for 500,000 cycles, usually at 130kph (80mph). Removed and inspected for cracks, deformation, damage.

Bending fatigue
Wheel is loaded with rated weight, 770kg in the case of an 18" or 19" 6UL, tire mounted and inflated.
Tire tilted to approximate steady cornering at 1G. Drum rotates the tire for 500,000 cycles, usually at 130kph (80mph). Removed and inspected for cracks, deformation, damage

13° impact test
Tire mounted and inflated. The impact is a flat plate aimed at the bead. It's 13° from horizontal. Sort of like sliding sideways into a curb. No Mustang has ever done that of course.

The last isn't listed on the JWL website but it's also performed. Well on 6UL's it is at least. That's the 90° "drop" test, which is just what it sounds like. Tire mounted and inflated. Loaded to max rated weight. Tire dropped straight down the same flat plate from about .5m (~20"). Think Dukes of Hazzard or WRC.

SAE standards up until recently, were pretty lax. A simple drop test and the wheel passed. No fatigue testing. In 2009, working with SEMA (Specialty Equipment Manufacturers Association) SAE significantly updated the J2530 standard to essentially mimic the JWL standard that most of the import wheel industry was already using. The SAE cornering fatigue test is now actually 1,000,00 cycles compared to JWL 500k. The impetus were a lot of hot rod and light truck wheels entering the market with suspect engineering diligence, process control or QC. These days, it's pretty hard to find an aftermarket wheel that doesn't meet at least one standard but they are still voluntary standards. The take away from this is that you should check your wheels for certifications. Particularly if you plan on donning helmet and pushing your car. You should see some or all markings SAE, JWL and VIA.

A few Japanese brands go a little past JWL standards for their performance/race lines. Rays increases the number of test cycles in their Volk brand race wheels, calling it JWL +R Spec 2 (so JDM!). Enkei also increases the number of test cycles in their JWL Spec E by 20% and drops the wheel from a higher point for the impact test. All good things.

At 949 Racing we took a different approach. We run the same number of test cycles as the standard JWL test protocol but each one is done with an additional 10% load. Everything else being equal, the stronger 6UL wheel should then be 10% heavier. We'll give you a hint.. it isn't. The Mustang wheel is a 5x114.3PCD, which for a 19" wheel means JWL standard is 690kg.The 18 and 19" 6UL's are engineered, tested and VIA certified at 770kg, a full 10% above industry standard. When we set those targets, early mass properties analysis (weight calculations in CAD software) indicated we could meet the same weighs as other 19" wheels on the market. After extensive tuning in FEA (Finite Element Analysis ), we achieved our goal of being amongst the very lightest S500 wheels on the market with a much higher test certification. This is why we are able to claim the 19" 6UL has the highest strength to weight ratio of any flow formed wheel offered for the Mustang. Yes, we are very proud of this achievement. Now you can be proud to run these on track and beat them up just the way we do on our race team cars.

Dynamic cornering fatigue load simulation. Instead of the wheel spinning with a tire, the wheel is held static and the load simulation input directly to the hub pad.

This is an example of the radial fatigue test. Note that the wheel is tilted at 13°


Impact test rig

?temp_hash=39bfbd5a7e6ae5d60f3b3f55dd9e9fc0.jpg
 

Attachments

  • 13_degree_drop_test_rig_web.jpg
    13_degree_drop_test_rig_web.jpg
    401.5 KB · Views: 263
Last edited:
All 6UL wheels are Low Pressure (LP) cast and Flow Formed (FF). Low Pressure casting is differentiated from gravity casting. Gravity casting is just what it sounds like, molten aluminum is poured into a casting mold. This can create a high quality wheel but intrinsically requires thicker spokes to allow teh aluminum to flow quickly into all the nooks and crannies without cooling to much. This means the spokes end up being thicker (and heavier) than needed. LP casting pressurizes the aluminum which allows it to flow quicker and into smaller spoke profiles. The speed and pressure reduces the chances for air bubbles and porosity. The resultant part is a bit denser, thus stronger. This allows an LP cast wheel to be lighter than a gravity cast wheel. Some manufacturers use the euphemism of "Tilt Casting", which is just a vat of aluminum tilted and poured into the mold via gravity. Enkei's RPF1 and PF01 use tilt casting with flow formed barrels for example.

F low forming is easier shown than described. We us the example of a potter spinning a bowl, using their fingers to shape and extend the bowl. Flow Forming is the same, only under heat and pressure to align the grain structure.

Flow Forming our 15x11 6UL 4 lug

This image below shows how Flow Forming allows a thinner barrel while increasing strength. While stiffness is important, failure mode is also important. Sooner or later, every wheel will yield if the load greatly exceeds design limits. When that happens, you want the wheel structure to bend instead of cracking or breaking. You can see in the image below, the thicker non-flow formed wheel fractures when it is bent past yield point. The thinner and lighter flow formed example bends but does not fracture. Flow forming compact and aligns grain structure in the alloy, much like die forging.

Additional processes and controls

VDH Helium inspection
-Leak detection

DMM
- Dimensional accuracy checks

Mass spectrometer
-Material analysis and verification

FEA - Finite Element Analysis
-computer simulations of load during design process

In house JWL test equipment
- We can test and optimize the wheels before they are give to 3rd party VIA certification labs.

FF_bend_slice.jpg
LP_Vs_FF_Grain.jpg
DMM.jpg
 

TMO Supporting Vendors

Top