Originally Posted by eclou

Toby are you concerned about the durability of these wheels?

Epic failure

Originally Posted by TT Surgeon

I have no interest in dynamags after looking at those pics Gene!

Originally Posted by RENNWORX GT3

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 8th and 9th 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:

* 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. Maximum “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>>
* A very small amount of the black Adheseal was extruded from the spoke end joint – excessive application??


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!

Originally Posted by RENNWORX GT3

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.