Wheel FAQs & Fitment Info

• 6UL’s are lug centric except our Spec Miata and Spec E30 specific 15×7
• A properly designed and manufactured wheel will not require hub centering
• The purpose of a centering ring is to facilitate installation. Once the wheels are torqued, they are just along for the ride and neither support or transmit load.
• Aftermarket wheels typically have two standardized hub center bores (“CH”) that allow the use of hub centering rings to adapt to various marques
• 5 lug wheels(including 6UL) typically 73.1 CH
• 4 lug wheel (including 6UL) typically 67.1  CH
• 949 Racing offers optional aluminum hub centering rings for ease of installation
• Plastic hub rings tend to melt with brake heat encountered in high performance environments

Lightweight racing wheels, such as 949 racing and similar brands, can have a finite service life. Over time, fatigue and small bends from impacts can reduce their structural integrity. Racing, track use and autocross place far higher stresses and loads on a wheel than street driving. For this reason, we do not recommend purchasing used wheels of any brand that have been used in a motorsports environment, if you intend to do the same. Like old race horses, once they have done their work, they get put out to pasture. Purchasing used wheels for 100% street and city driving can be OK. But even then, carefully inspect your used wheels prior to purchase for cracks, bends, gouges, dings. When in doubt, stick with new wheels for your high performance car project.

• Gen 5: Sanger  6UL  Coto  2022+

  Gen 5 wheels can be identified by the flat, flush center cap. They also have chamfered spokes (beveled edges) and ball mill (grooves in sides of spokes.

  • 10% higher load ratings than JWL/DOT standards. This is proven to reduce fatigue cracks to zero even with competition style driving. A feature we were first to bring to market in 2015 with our 15×10. This effective approach has since been adopted by other wheel companies.
  • Tilt Casting Technology. Tilt casting creates a much denser crystalline structure in the final product. This translates to greater tensile strength and elongation compared to gravity or low pressure casting which most of the industry uses. The result is the highest strength to weight ratio of any casting process.
  • Benchmark stiffness and fatigue life against the best wheels in the industry. We accomplish this by obtaining other brands wheels, 3D scanning, creating CAD models, simulating loads in FEA then physically testing the wheels in a US Lab. We know how strong the best are so we match or exceed those values.
  • Knurled beads. The feature we first brought to aftermarket sports car wheels in 2009. Then an industry first and now widely adopted by other brands.
  • Our proprietary 180° opposed dual valves for nitrogen/ dry air purging
  • Flow forming barrels. This allows greater bending resistance, improved fatigue life and reduced weight.
  • Valves set behind outer flange. This prevents the valve being damaged in wheel to wheel racing or even an accidental curb scuff.
  • Anvil inner flange for increased resistance to bends from potholes and trackside excursions
  • Lifetime warranty.

Gen 3 6UL   03/12 – 6/13 (Discontinued)

For the generation III design, we increased the load capacity to 500kg and used the more stringent VIA test protocol. The wheels gained a few ounces and greater fatigue life. The Gen 3 can be identified by the VIA stamp near the valve hole. The Gen 1, 2 and 3 designs are all 100% compatible with each other and can be mixed on the same car. Color variations may occur between generations.

Gen 2 6UL   01/09 – 02/12 (Discontinued)

 The second generation 6UL wheels are low pressure (LP) cast and T6 heat treated. LP casting refers to the aluminum being forced into the wheel mold under pressure. This pressure eliminates the possibility of bubbles and voids in the aluminum casting. It also compacts the aluminum which allows a higher tensile strength to be achieved with the same material. Gravity cast tooling requires larger wall thickness to allow the molten aluminum to flow into all the small features and crevices of the mold during filling. The design benefit of the new LP technique is that the engineers can optimize the thickness of each part of the wheel without really needing to allow for material flow. This optimization reduces weight without any decrease in strength.

With a gravity cast wheel, the center hub area is the last part of the mold to be filled by the molten aluminum so it is more prone to unwanted porosity or voids. To combat this potential weakness, the hub area is overbuilt to ensure failsafe strength. With the new LP casting, the mold filling and density is the same throughout the wheel structure so the hub area can be further optimized and lightened.

While we kept the same unique 6UL look, the engineers needed to create an entirely new engineering drawing and tooling for the LP casting process. We took this opportunity to reevaluate every single area of the wheel, perform further FEA optimization, strengthened and lightened wherever possible. It takes trained eye and both wheels in hand to spot the differences but there were more than a dozen little tweaks to the Gen II compared to the Gen I.

The end result is a wheel that’s about 5% lighter with nearly twice the fatigue life and substantial gains in strength. The Gen II also end up being a bit stiffer and that’s directly creates more consistent contact patch loading. Few tuners ever think about this but a wheel that’s too soft and flexible will actually deflect under hard cornering loads enough to reduce active camber. Stiff wheels are good.

Gen 2s can be identified  by the ” 6UL ” embossed right on the face of the wheel. The center bore on all versions is 67.1mm, which allows the optional use of standard size hub centric rings.

6ULR 17″ (Discontinued)

The 6ULR is also be LP cast like the gen 2 6UL but features a flow formed, or spun forged, (also known as rotary forged) outer rim or bell. This is a one piece design. The still molten aluminum wheel with it’s center section already shaped is then spun. The outer rim is rolled between a mandrel and inner wheel form to slowly drawn into the final shape. With roll forming, the outer rim is actually formed under extreme pressure so its a form of hot forging. This pressure further aligns the grain structure in the outer rim area which allows the absolute minimum possible material be used for a given strength target. The mandrels are CNC so an engineer can precisely vary the thickness to a few thousandths of an inch based on the results of FEA (Finite Element Analysis).

Gen 1 6UL 01/07 – 07/08 (Discontinued)

The first generation wheels were gravity cast and T4 solution heat treated. The center bore on all versions was 59.1mm, except the Spec Miata version which was 54.1mm hubcentric. The gravity cast 6UL’s proved to have a great strength to weight ratio.  Gen 1 6UL does not have 6UL cast into the face.