For what its worth, I have seen custom-machined aluminum wheels fail at the track in exactly the same manner. The car was running super wide Hoosiers in the front and back and on a long sustained curve at extremely high speeds the outside front wheel failed.

 

Chances are if it was a custom machined wheel, it wasn't put through the proper testing, no?

 

I'm sorry to hear about your damaged wheel and your accident. I must say seeing the pic of the destroyed Dymag makes me rethink the wheels for my car. I would not want to have that image of wheel failure in my head at 185 mph. My car sees high speeds, thats one reason a bought it. For now I couldn't pull the trigger on Dymag wheels. Maybe with HRE help they can make it work.

 

And dymags may be fine for road and occasional track use, But I am shopping for track wheels that I can run with slicks on the track, for every event. They will likely never touch the street. I, much like M3 S3-R, don't want to be coming into a turn at the track and wondering it my wheels are going to make it through this lap. Do any of the professionals in the wheel business have a sample of what the test results should look like, and what numbers I should expect to see in which fields? Cause right now you could tell me that they are TUV approved, and all I can tell that means is that they are ok for use in a few countries with street tires.

 

4CEFED
I handeled the situation of the broken center for Dymag.
The wheel was broken at a track event in Mexico the customer runs full slicks all the time at the track and these wheels had about 60 full track days on them unfortunately they were not checked after each event and the spoke developed a hairline crack that started from the engraving on the back of the spoke. They stamp the back of the spokes with the model number of the mold. The crack propagated causing the spoke to break in half and transfering the weight load the the remaining spoke as he continued to run the wheel then broke as he was in a straight line braking zone at the end of a staright away.
The damage to the car was minimal about $10k and Dymag paid for the damage and the full set of wheels the car was back at the track in 10 days time and the customer was fully reimbursed.
The magnesium center was sent to a testing lab here in the U.S. to make sure that it had all the properties it should have for cast magnesium the test results came back with passing results and upon inspection of the wheel it was determined that fatigue was what caused the failure.

These wheels have been used in racing by a BMW British Turing car team that competed two season with no problems and won a 24 hour race as well as a podium in a 12 hour race and many sprint races.
GMG used the wheel for two full season on the Time attack series with no issues and even said they gained time at Infineon as they could drive over the curbs much harder then they could with the BBS race wheels as the Dymag absorbed the impact and the BBS would have bent

Dymag has changed the center disc material to a forged exotic metal called Magnalium this is a hybrid of Magnesium and Aluminum and contains the best properties of each. The magnesium offers the lightweight and strength and the forged aluminum offers the non-corrosive property that is one of the downfalls of magnesium.

This new center disc material will be on every new Dymag wheel starting delivery next month we stopped taking oders in August so that we could be sure of the testing of the new material I will attach the updates I recived on the testing but you can be sure that DYMAG wheels are properly tested to the multiply requirements of TUV,JWL,DOT and they have passed independent test by General Motors in both the Cadillac and Corvette divisions as well as Mclaren.

I want people to understand that many brands of wheels have failed at some point but track events is where you hear and see about them but what you need to know and understand is how does the company stand behind its product and I think you can see from this story that Dymag handeled this customer quick so that he was back on the track at his next event.

Following is the test results in progress on the new Magnalium center Dymag wheels these same test were used in the original magnesium centers as well and then you will read they have done real world testing on the track at SPA and Silverstone in the last month.

The wheel has now completed 1 million cycles of cornering fatigue comprising of 500,000 cycles at 550kg static wheel load (2,200kg gross vehicle weight) and then 500,000 cycles at 600kg static load (2,400kg gross vehicle weight). The test load has a large safety factor incorporated into the calculation, which gives a test load of 2,200 ft lbs at 550kg static and 2,500 ft lbs at 600kg static. The British Standard test duration is only 150,000 cycles and so completing 1 million cycles at these loads with no damage or air-leakage is an impressive result." The radial fatigue test has thus far completed 500,000 cycles at 550kg static load, which gives a test load of 1,237kgs. This is the required British Standard test duration. This test will run on to a million cycles, which is twice the required duration and then assuming there are no problems; we will increase the load and retest. We have also arranged a race test at SPA on 8<SUP>th</SUP> and 9<SUP>th</SUP> October on a race prepared GT3, where it will be pushed to the extreme including driving back and forth from the shop:

Here is the report from SPA:

Although I have yet to receive the full results of the tests at Spa, Jon Oakley has given me an interim review of what happened whilst I was in Italy, the car was fitted with the latest Pirelli Corsa competition tyres that are road legal and was driven to Spa and back very hard on the same set of tyres, including the old concrete Jabbeke Highway which is a very fast freeway that creates incredible noise and vibration from the surface and is renowned as a wheel breaker (Jaguar did the original testing of the XK120 there in 1959). Wednesday morning was raining lightly and then the circuit dried, the rest of Wednesday and all Thursday was dry. There were only 2 other cars quicker than the Oakley Porsche, a GT1 Aston Martin and a DTM Mercedes, the Oakley 997 GT3RS is a very quick car with a very efficient Oakley Design Ti exhaust, Intrax suspension, carbon cage, ceramic brakes, race calipers etc and is quicker than the Porsche Supercup cars. Jon is a good, reliable and quick race/test driver who gives good feedback beyond the data logger information. The following observations were as Jon reported:
<O</O

• The wheels have not cracked
• The car handled better and steered more precisely on the Al centre (stiffness) compared to the Mg centre – Jon was able to conduct a back to back comparison. <OMaximum “observed” temperatures within the rim (infra red pyrometer readings) were 92°
• There were absolutely no leaks
• There was no creaking noise
• There was no grey streaking down the tyre sidewall from the carbon/metal joint<O></O>
• A very small amount of the black Adheseal was extruded from the spoke end joint – excessive application??

<O</O
The wheels should be back available to us by Tuesday, so we should strip and examine the joints/centres etc carefully. Jon will give us a full report with lap timings on the treatments and settings I asked him to give the car to fully load the wheels, he sounded a very happy man!!


As you have read the testing is very extensive and they used this product for two years in racing before they introduced it to the market in 2006 there have been some issues with leaking and the centers making noise but it was all due to the old technology magnesium centers so in an effort to eliminate these problems more testing and the development of the Magnelium has come to pass.

The new centers will be avilable from December and Dymag stands behind its prodcut and its customers. I have been in the wheel business 16 years and I have run Dymag wheels on my 996 GT3 at the track for two years.

Please understand I am posting this information to clear up any misunderstanding of this wheels broken center which has been addressed and corrected and you can see that the carbon fiber held up very well under the conditions.

Good Luck to you in you choice for wheels and I hope this clears things up about Dymag!

 

Here is the lab we use in the U.S. -Standard testing Labs


Tire and wheel evaluations include:

• Fatigue and Dynamic Durability testing specified by DOT 109, 119 and 139. Weibull Analysis and other statistical methods are available.
• High speed Durability testing(up to 230mph)
• Rolling resistance testing Passenger, Medium Truck Spindle Force Method per SAE J-1269
• Coast-down rolling resistance testing per SAE J-2452
• X-ray and Shearography non-destructive analysis
• Bead Unseat and Plunger Energy per SAE J-916c and DOT 109, 119 and 139
• Load deflection and footprint evaluations
• Dynamic Impact testing with cleated roadwheel.
  Wheel impact test by SAE, ISO and JASO methods. Nominal wheel diameters up to 16.5". Force and velocity requirements to GM requirements.
• Belgian Block - Testing for wheel covers, rings and hub caps, as well as tire durability.
• Strain Gaging
• Salt/Acid spray - Salt spray ASTM B117 method and GM WL 15-5-81 stress corrosion test. CASS acid test ASTM 368.
• Hydroburst Testing - Strength studies for tires and wheels.
• Instron Studies - Rubber-to-cord adhesion, strength and elongation.

 

Rennworx GT3 great post with lot of info. So what is Dymag going to do with all the wheels all ready produced? You have people who paid 10k for wheels that have issues. If you have any info on the joint venture between HRE and Dymag, could you please share with us.
Thank you,
Marco

 

Dymag will offer an upgrade to the Magnalium centers if the customer has issues. Not all wheels have had problems but in cases of future problems will will address these on a case by case scenerio. A letter wil be mailed to these customers in the next few weeks.

Dymag has agreed in principal to supply HRE with Carbon Fiber barrels. Dymag feels that this is a good partnership as HRE has a great reputation and will help advance the education of carbon fiber to the world market.

Dymag will continue to develop and enhance the current wheel while also looking to the future with some new and exciting technology.

Dymag will not sell the barrels to just any company only a select few that understand the true testing and engineering of a high performance wheel.

 

Thanks for your detailed input. One question, the loads for the vehicles were 2200. You have to figure the average sports car with driver and passenger is pretty close to that. However with down force and cambered roads, I would assume the apparent weight of a vehicle, might be quite a bit higher.

Given that fatigue and failure may not come at say 2200 for 500,00 cycles, does not necessarily mean that 2500kg it won't fail much, much sooner?

I don't know at all. Just raising questions. I guess if we knew how champions, HRE etc. are tested, that would be helpful in knowing in whether Dymag is over the top, or barely cutting mustard.

 

2,200kg is 4,850lbs most sports cars are not in excess of 5,000lbs. Also as they test they keep increasing the load until failure the results I posted were early in the testing I have not receive the final results.

Most good wheel companies use the standard set by TUV as it is the most difficult the easiest is the DOT spec.

 

FYI

1. 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.
2. 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.
3. The testing requirements of J2530 are composed of 3 performance tests.
4. 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.
5. 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.
6. 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.
7. The quantity of wheels required to complete the testing are as follows:
8. Cornering Fatigue = 2 up to 7
9. Radial Fatigue = 2 up to 7
10. Impact = 2
11. 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.
12. Marking requirements:
    The markings that are required by DOT are as follows;
13. 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.
14. Wheel size (example 15x8).
15. Wheel manufactures name, trademark or symbol.
16. Date of manufacture of the wheel, indicating month and year.
17. Manufacturers part number or code.
18. Country of manufacturer.
19. The symbol “DOT” constituting a certification by the manufacturer of the rim that the rim complies with all applicable vehicle safety standards.
20. Here is a simple way to determine what a safe wheel load rating should be for your vehicle.
21. 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.
22. 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
23. In summary, unless your car 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 companies out there selling, building, importing and modifying wheels that when they read the above, it will be the first time they’ve heard it

 

FYI, Oakley Design are due to receive my set of wheels made using the new centers tomorrow. They will shipped to the US next week. I will give you feedback on the construction, handling etc in due course.

(Yes these are the first production set, Oakley have the prototypes on their GT3 and GT3 as commented earlier)

 

Yes we will receive our test wheel next week and send it to STL for testing here in the U.S. before we release the new product. We just want to double check all testing to be sure the new product has no issues.

 

props for Dymag resolving that issue very professionally.

 

Holy thread revival.

Isn't Dymag deceased?