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Unread 12-08-2011, 03:18 PM
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Default New Product: D-Force 18x10 for S197 Mustang & GR Subaru STI

S197 Mustang and GR Subaru STI racers - rejoice! There is finally an 18x10" wheel that fits your cars properly which is lightweight, backed by a US company, and is around $300 each. The first batch of 100 wheels are being built and are ready to order online, available exclusively from Vorshlag. This production run is scheduled to arrive in March 2012. Order now if you want to get a set from this first batch, otherwise you will be lucky if you see a set before summer 2012. We suspect that this production run will sell out by the end of December.

> Pre-Order for S197 Mustang Here! < > Pre-Order for GR Subaru STI Here! <





As you know Vorshlag has been working with D-Force Wheels since 2007 as an engineering partner and dealer. We've helped them come up with a number of BMW wheel fitments and now we've teamed up to offer an 18x10" wheel in the 5 x 114.3mm bolt circle, with the correct offset & caliper clearance to fit both the S197 Mustang and GR Subaru STI. The offset we chose is ET43, to fit the 2005-2012+ "S197" chassis Mustang front and back with no spacers needed (which just so happened to fit the Subaru STI just as well). Caliper clearance is HUGE - with the optional 14" Brembo front brakes on our 2011 GT you can fit your hand between the back of the spoke and the caliper (the stock 19x9" wheel had only .050" caliper clearance!).


Some of the many different wheels we've purchased and tested with on our S197 Mustang - none of which fit in 10" widths

If you have been watching the build thread on our 2011 Mustang GT 5.0, our S197 test mule that we've used in NASA Time Trial and SCCA STX autocross racing, you know how thoroughly we have been looking for lightweight wheels for this chassis since August of 2010. For such a high volume car there were surprisingly few lightweight/wide wheel options available in 10" or wider sizes. We found several 18x9" and even a few 18x9.5" wheels that fit, but nothing in 18x10". This seemed odd to me, as it is a BIG car that needs a lot of tire under it to handle well on track or to carve through the cones - 275mm tires are perfect, but really too wide for a good fit on a 9" or 9.5" wheel.

The vast majority of wheels made to fit these Mustangs are cheap/import/reproduction copies of factory Mustang wheels in 18x9.5", 18x10 or 19x10" sizes, but with all of the 10" wide wheels have weird offsets that do not fit the S197 car (they are made to fit the previous generation SN95 Mustang). All of these wheels tend to be lower cost ($200-300/each) but VERY HEAVY (25-30+ lbs each!). Not good.


Left: D-Force BMW 18x10" wheel is 18.7 lbs and $309 retail. Right: The "Boss302R" 18x10" BBS is 21 lbs and $637/each; used on GRAND AM race cars

Heavy wheels are bad for racers for several reasons: the vehicle has to speed up and slow down that rotating mass of each wheel/tire, which hurts forward acceleration and braking deceleration. Second, the shock has to control more unsprung mass over every bump, making it work harder. And third, anything that lowers overall mass on the car is a win, improving all acceleration vectors (lateral, fore, aft). So that's the number one criteria on a motorsports wheel - make it light!


Left: Stock 2011 Mustang GT 19x9" wheel and 255/40/19 tire is 57.2 lbs!? Right: factory wheel is 19x9" ET42, JWL approved, and cast in China

We also wanted to make a bolt-on wheel that was wider than the 17x8, 18x8.5" or 19x9" factory S197 GT wheels. More wheel width, means more supported tire width, which equals more GRIP. We took a lot of measurements, bought several test wheels (WedsSport, Enkeis, Rotas, and more), and finally concluded - there was simply nothing available in 18x10", under 25 lbs., and under $600/wheel that fit this Mustang chassis without poking the wheel past the fender lip and/or cleared the front brakes.



D-Force made a prototype set of 18x10 wheels for our Mustang back in July of 2011 and we've been pounding out street, track and autocross miles on these wheels for the past 5 months. They have performed flawlessly with multiple sets of tires, including 265/40/18 Yokohama AD08 and 275/40/18 Bridgestone RE-11 models. The extra inch of wheel width and the extra inch of tire width that the 275mm package offers was a huge improvement to performance, and the wheel and tire finally "looked" right for this big car.



We also tested this 18x10 D-Force wheel on a GR Chassis Subaru Impreza STI (2008+), which it also fit perfectly without the use of any spacers. The car above was tested with the 265/40/18 tire, and that seemed to work perfectly. I would also recommend a 275/35/18 tire for this GR chassis. Both sizes are close to the OEM tire height, as the Subaru doesn't use super tall OEM tire (27"!) like the modern Mustang, where the 275/40/18 works better.
  • More Mustang 18x10 D-Force pictures here
  • More Subaru 18x10 D-Force pictures here

D-Force is known for high quality, light weight wheels at great prices. Yes, these wheels are imported, but they are made at one of only 4 factories in the world licensed to use the "Flow Forming" / semi-forged technology, and that also supplies wheels to several OEMs.

More on D-Force Flow Formed wheels: "The center area of the wheel is first cast in a low pressure mold, then removed and spun on a CNC machine where it is pressed, heated, and spun simultaneously, resulting in a semi-forged finish that forces the aluminum in the barrel area of the wheel to be thinner yet more dense, allowing more strength from less material, therefore reducing weight."



There are two colors available in this first production run: flat black and silver (see above). Silver is a popular choice, as it works well on street cars with any color car. Flat black is also popular with racers, as it hides brake dust. The prototype 18x10/5x114.3 wheels were built to JWL approval, which is 1560 lb load rating per wheel. The production 18x10/5x114.3 wheels are being built to have a 1800 lb load rating per wheel, and will weigh approximately 1 pound heavier than the prototype 114.3 wheel (19.2 lbs), for use on these heavier GR and S197 chassis cars.

Note: This wheel might fit other cars, such as the Mazda FD RX7 or Mazda RX8, but we haven't tested those cars yet. We tried it on an Mazda NC MX-5 and it did not fit.

> Pre-Order for S197 Mustang Here! < > Pre-Order for GR Subaru STI Here! <

Last edited by Fair!; 01-25-2012 at 11:01 AM.
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